literature review of dairy farming

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Developing ‘Smart’ Dairy Farming Responsive to Farmers and Consumer-Citizens: A Review

Maeve mary henchion, marion beecher, áine mackenwalsh.

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Correspondence: [email protected] ; Tel.: +353-1-8059515

Received 2022 Jan 1; Accepted 2022 Jan 28; Collection date 2022 Feb.

Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( https://creativecommons.org/licenses/by/4.0/ ).

Simple Summary

Dairy production has evolved over many generations to be an important source of high-quality nutrition for a significant proportion of the global population. However, it needs to evolve further to ensure it contributes to sustainable diets. Technological innovation can be a key enabler. It is also the case however that innovation brings about significant change, and can introduce unexpected, unintended and undesirable consequences, which are experienced differently by different actors on the ground. Thus, a major challenge is turning good science and technology into positive and innovative outcomes for society in an equitable way. Drawing on concepts from Responsible Research and Innovation (anticipation, inclusion, reflexivity and responsiveness) and Food Systems thinking, the authors reviewed the academic literature to consider the perspectives of different actors relating to technologies on dairy farms. It considers ‘smart’ on-farm technologies at three key stages of the dairy production cycle—breeding, feeding and milking—through the lens of two actor groups. It considers the farmers who may(not) adopt such innovations and the consumer-citizens who will(not) purchase/accept the resultant on-farm practices and foods. It highlights some differences between and within these actor groups, but also identifies commonalities, including tensions, faced by both groups. Dairy production in the future, thus, is not only challenged with embracing advanced technologies, the process by which such technologies are designed and selected must also be ‘smart’.

Innovation has resulted in more dairy products being produced with less inputs than ever before. It has also affected how animals are raised, the structure of the sector and the nature of products produced. Not all impacts have been positive. As disruptive technologies—such as precision farming and robotics—herald significant change, it is timely to reflect on the perspectives of different actors on innovations within the sector. Drawing on a review of academic literature, this paper considers farmers’ and consumer-citizens’ perspectives; as expected, their diverse knowledge, interests and values surface a range of perspectives. To provide focus to the study, it examines technologies across three stages of the dairy production cycle: breeding, feeding and milking. It finds that consumer-citizen and farmer perspectives have been examined by researchers in several countries, using a variety of methods, across a range of technologies. It finds both areas of agreement and tension within and between consumer-citizen and producer cohorts. While differences in knowledge account for some variation, differences in values are also significant. The extent to which efforts can and should be put into addressing differences is raised as a point for reflection.

Keywords: responsible research and innovation, RRI, consumer, citizen, farmer, attitude, dairy, food system, innovation

1. Introduction

The dairy sector has featured as an important component of the domestication of livestock for food purposes for about 360 human generations [ 1 ]. Advances in science and technology have supported the introduction of many on-farm innovations. Such innovations mean that the way animals are raised on farms has changed greatly over the past century [ 2 ] and such innovations have also had structural impacts on the sector through promoting specialization, mechanization and intensification [ 3 ]. Indeed the scale and intensity of livestock farming have increased significantly over the past 50 years [ 4 ]. This has had positive economic impacts including greater feed conversion efficiencies and increased yields, resulting in more dairy products being produced with less inputs than ever before, reduced manual working on farms, improvements in food safety and quality through the adoption of food safety and quality standards, and reduced costs of dairy products [ 5 , 6 ]. While the primary aim of such developments is to increase agricultural output and increase the availability of safe, affordable food, some developments have negatively affected other aspects of sustainability, including animal welfare [ 7 ], the environment, worker safety and rural economies [ 2 , 8 ]. For example, changes in farming practices associated with specialization and mechanization have resulted in reduced space allocation to animals, with some animals given very limited/no access to the outdoors. It has also resulted in animal husbandry practices that may be painful, for example castration and debudding, and practices that interfere with ‘natural’ behavior, e.g., removing calves from their dams [ 9 ]. These and other practices have provoked negative reactions, often based on ethical perspectives, from citizens in particular [ 9 , 10 ]. Intensification has also resulted in the increased use of (synthetic) inputs, with negative impacts on water and air quality, biodiversity and soil health. Such realities have led to questions about the sustainability of dairy production arising in relation not only to trade-offs across economic and environmental aspects of sustainability but also in relation to social (intersections between different groups or individuals) and temporal (intersections between different generations) trade-offs. Critical questions also arise in relation to the social acceptance of certain on-farm practices. Indeed, notwithstanding a progressive loss of connection between consumers and producers, leading to a lack of knowledge of animal production management approaches and practices by the general public [ 11 ], consumers are now increasingly questioning production systems and wanting to know more about how their food is produced [ 12 ]. While dairy production tends to have a relatively positive image amongst the public [ 9 ], being associated with animals grazing pasture and living in the countryside, practices in dairy farming are increasingly subject to public scrutiny [ 13 ].

Thus, the sustainable production of food, including dairy, to meet the demands of a growing global population cannot be assumed and it is increasingly recognized that there are “externalities” associated with food production that are often not sufficiently taken into account. These externalities are defined as both costs and benefits that arise due to the production or consumption of goods that are not reflected in the market price. Examples include ecological effects, water quality, resource depletion, greenhouse gas (GHG) emissions, animal welfare, cultural heritage, social costs associated with labor and public health effects [ 14 ]. Such thinking, and growing awareness of negative externalities in particular, has led to calls to transform the food system. A report by the Food and Land Use Coalition estimates that the global cost of these externalities is in the region of US$12 trillion a year, rising to $16 trillion by 2050 [ 15 ]. In this context, “top-down” government policy (dis)incentives are often relied upon to change behavior to influence the magnitude and distribution of costs and benefits. Taxes, regulations and financial incentives are some of the options available to governments. Another complementary option is to draw on the work of researchers in the behavioral sciences to use “bottom-up” approaches to change practices in industry [ 16 ], and to engage with stakeholders to clearly identify and address any potential unintended consequences as early as possible. A third option is to draw on advances in science and technology [ 17 ], including nature-based solutions, in an attempt to eliminate potential trade-offs. It is highly likely that responses to the call for food system transformation, particularly in the current context of the urgent need to address climate change, will lead to a new era of disruption and transformation in the agricultural sector, with significant consequences for the role of dairy farming, and the foods that consumers are willing to purchase. However, turning good science and technology into good practice on a dairy farm is a challenge. Reflecting a view that technologies are “socially shaped, co-created by their makers and users to perform roles that can change over time, and be different, for different groups of people“ [ 18 ] (p. 518), the term technology in this paper is used broadly and can encompass any or all of three layers—a physical object or artefact, a process or activity, and what people know as well as what they do [ 18 , 19 ] (p. 518).

The purpose of this research is to contribute to responsive and sustainable research and innovation practices within the dairy sector by surfacing the views of potential users and/or those who may be positively or negatively affected by such developments. Drawing on published academic literature that reports the results of qualitative and quantitative data collection methods designed to elicit such information, we identify some of the impacts that could arise with the introduction of key technologies in the dairy sector. We do so through the lens of two particular actor groups who have often tended to have little agency or power within the research and innovation process to date: farmers and consumer-citizens [ 20 ]. These actors represent opposite ends of the traditional value chain, thus potentially capturing some of the diversity of perspectives that may exist; previous research provides evidence of differences in perspectives between these cohorts on issues relating to agricultural production [ 21 ]. Through a series of specific technologies, across key stages of the dairy production cycle, we consider what we know to date about how farmers and consumer-citizens view and value aspects of these technologies. We do this to (1) illuminate the range of perspectives that may exist across these cohorts, (2) explore the extent to which differences exist within these cohorts, and (3) propose reasons for such differences. In this way, we can highlight knowledge gaps within the literature and suggest factors to be considered and strategies that could be adopted to support responsive and sustainable research and innovation practices. The paper starts by discussing Responsible Research and Innovation (RRI) and the centrality of ‘inclusion’ for societal responsiveness and food system transformation. It then argues for the consideration of on-farm technologies through the lenses of two key actor groups: the lens of farmers who may/may not adopt such innovations and the lens of consumers-citizens who will/will not purchase/accept the resultant foods. The following section considers technologies and associated practices at three key stages in the dairy production cycle—breeding, feeding (calf and cow) and milking—that are adopted on farms and/or are moving into widespread adoption. The paper concludes with a discussion on areas that researchers, extension workers and policy makers may wish to consider in developing more responsive and socially acceptable solutions to sustainability challenges facing the dairy sector.

2. Responsiveness to the Needs and Values of Farmers and Citizen-Consumers

New science and technologies are presenting opportunities to radically change how dairy food is produced and delivered to the market. They hold a lot of promise for ensuring a more ‘responsive’ dairy sector, a dairy sector that is more sustainable, safe and secure. Disruptive technologies and innovations such as precision farming, agro-genomics, robotics and digital traceability systems could be “ushering in a fourth agricultural revolution” [ 15 ], with some arguing that a transition is already occurring in the farming sector with the introduction of new advanced innovations and digital technologies [ 22 ]. In this argument, technological innovations are viewed as key enablers and drivers for supporting more sustainable, safe and secure farming and food systems [ 23 ], addressing some of the key challenges facing the dairy sector such as sustainability, climate change, food quality and nutrition, and animal health and welfare and “neutralising” some of the trade-offs that are implicit across different sustainability dimensions. However, such innovations also bring about significant change, and can introduce unexpected and unintended consequences in areas such as digital exclusion, unequal power relations, animal-human relationships, data governance, skill and identity loss [ 23 , 24 ].

Numerous scholars have called for more inclusive approaches to be used in research and innovation in agriculture broadly [ 25 ] and dairy farming specifically [ 20 ]. Arguments include the instrumental argument that understanding the perspectives of different actors can help to improve milk production practices on farm [ 26 ] and that societal preferences will continue to influence food production including dairy farming [ 5 ]. More normative arguments claim that unless there is an understanding of the needs and expectations of the public, the adoption of agricultural practices that are inconsistent with public expectations may undermine social sustainability [ 2 ].

2.1. Responsible Research and Innovation

Responsible Research and Innovation (RRI) is a framework championed at national levels and within the European Union to streamline the design and deployment of technology and innovation, and to ensure it is done in a manner that is reflective of and responsive to diverse societal needs and values [ 27 , 28 ]. The principles covered under RRI echo those from movements such as ELSA (Ethical, Legal and Social Aspects) and Public Understanding of Science. Four dimensions of RRI have been identified and described: anticipation, inclusion, reflexivity and responsiveness [ 27 ]. Anticipation encourages researchers and technology developers to explore possible impacts of their innovations and research, both the short-term and long-term consequences, and the positives and negatives. Inclusion or engagement highlights the importance of ensuring diverse actors have a voice during the innovation process from start to finish; allowing researchers and technology developers to be aware of diverse values, needs and concerns. Reflexivity encourages researchers and technology developers to consider their own personal values and conflicts of interest and the views of others. They are encouraged to reflect all the while on how these different values may converge or diverge, and what this may mean for developing and implementing new technologies and innovations. Finally, responsiveness occurs when researchers and technology developers make an active effort to respond to these inputs by altering their research or innovation trajectory accordingly.

The RRI framework is intended to support decision-makers driving technological innovation and to act as ‘a scaffold for raising, discussing and responding to questions of societal concern’ [ 29 ] (p. 245). There is no set or organized process for carrying out RRI exercises, although scholars argue that the lever of inclusion is central for operationalizing all dimensions [ 23 ]. One of the key principles of RRI is the need for inclusivity and engagement with diverse actors. Processes, such as collective experimentation and participatory design, or ‘co-design’, which facilitate dialogue and deliberation, are at the heart of this principle [ 30 ]. This anticipatory or upstream engagement enables conversations to happen between diverse actors before, and during, technology development and implementation to ensure that different values are accounted for and to avoid technocratic decision-making [ 29 ].

2.2. Inclusion of Citizen-Consumers and Farmers

In parallel with discussions on RRI, the need for inclusivity in how food systems transformation occurs is also emphasized. This is because various actors are likely to have different perspectives on the supports and incentives that should be provided, and from what source, to effect changes in the food system. The OECD [ 31 ] highlights likely differences, and thus potential sources of frictions, in terms of facts, expectations and values amongst different groups when seeking to develop policies and make decisions to support an effective food system, emphasizing the need to understand such different perspectives. In relation to the livestock sector, the organization indicates a role for independent advisory groups to establish the facts, but cautions that they are not always widely accepted by the public or stakeholders, and that there is a need to have a shared understanding of the facts amongst all stakeholders [ 31 ]. They suggest that the interests of different groups, including those with livelihoods at stake, can be surfaced through public consultations. In relation to values, they reference the importance of farmer identities and their sense of belonging to a rural community. They argue that “… making better policies for food systems not only requires a rigorous understanding of how the world is, but also a shared view of how the world should be” [ 31 ] (p. 10). Given the trade-offs that are inherent in developing sustainable food systems, they conclude that “a trade-off cannot be resolved on purely technical grounds, but involves an element of societal choice” [ 31 ] (p. 82).

As argued, there is a need for better inclusion of diverse actors’ values and needs in the decision-making surrounding new technologies and innovations in the dairy sector. Specifically, this paper argues that the views of two particular societal actors should be better considered: farmers, and consumer-citizens. Such groups are often presented in the literature as opposing or even in conflict. Moreover as they are likely to have different levels of knowledge and experience, different interests and draw on different value sets, it is likely that they assess individual farm practices in very different ways [ 32 ], thus contributing a diversity of perspectives. Finally consumers and citizens often tend to be excluded or overlooked in innovation activities relating to dairy technologies [ 20 , 33 ].

Consumption patterns—what consumers choose to eat and influences on such choices—are critical factors shaping how food and land use systems evolve. Moreover, public opinion can become a major driver for industry changes [ 34 ]; even if attitudes do not influence purchasing behavior (consumer perspective), moral discomfort can be expressed as support for changes in legislation (citizen perspective) [ 32 ]. Given the historical fall-out of failing to gauge public risk perception on agricultural issues in the past (e.g., BSE, GMOs) [ 4 ], there is a recognition that socio-cultural perspectives, including consumer-citizen perspectives, are inadequately reflected in discussions on more recent on-farm technologies [ 22 , 33 , 35 ]. Furthermore, it is evident that increasingly urbanized consumer-citizens are asking more questions about production systems, that there is a shift in agriculture from being an activity that is almost wholly rural to one that is more subject to urban influences and that non-farming citizens may have dissonant images of livestock farming, varying from what is perceived as the highly idyllic to the shocking [ 4 ]. Livestock products are of particular interest to consumer-citizens in relation to livestock treatments and animal welfare [ 11 , 36 ], as well as other factors including the environmental impact of production, food safety concerns and the social implications of various production methods [ 36 ]. Studies that seek to identify consumer-citizens’ perspectives on an “ideal farm” demonstrate that consumer-citizens’ perspectives can be multi-faceted. For instance, in a US study that focused on identifying the ideal pig farm from a consumer-citizen perspective, respondents were reported to consider social, environmental and economic aspects, and to do so from different perspectives. For example, while they considered animal care, with a focus on quality of life, they also considered profitability, emphasizing that the ideal farm should be a profitable business operation and included considerations of workers’ rights and welfare [ 37 ]. Another US study that specifically focused on dairy production also found that research participants referred to social, economic and environmental aspects, albeit with a strong emphasis on the animal, both in terms of natural living and animal health, based on ethical arguments and instrumental arguments relating to the consequences of animal care on the quality of milk (and by inference human health) [ 38 ]. As noted by the Food and Land Use Coalition “Empowering consumers to make better-informed decisions that are healthier for them and for the planet ignites the whole reform agenda” [ 15 ]. A prerequisite for approaches to food systems transformation that empower consumer-citizens is to understand their perspectives.

While, with some key exceptions, there has been minimal activity engaging the general public in conversations around new (digital) technologies in farming, more recent studies have sought to involve farmers as end-users to a greater extent [ 39 , 40 , 41 ]. This paper focuses on farmers as their decisions and actions have significant impacts on how food is produced, and the quantity and nature of inputs that are available for the next stage in the supply chain. However, they are also significantly impacted by changes in the food system. They currently face increasing risks and pressures as a result of, amongst other factors, climate change, changing public policies and support regimes and increasingly stringent customer demands. Furthermore, demands from the public, through civil society organizations for example, feed into how they conduct their business. As the food system changes, farmers and their employees need to be able to remain in the game, and to be paid fairly to produce healthy and environmentally friendly food, as well as other goods and services. In this way, it is important to consider their perspectives to ensure a just transition.

In addition, farmers have a role as sources of knowledge and as innovators in their own right. The multi-actor approach that is championed by the European Commission’s DG Research, and innovation systems thinking, recognizes that farmers are not only passive recipients of knowledge but that they can/should be actively involved in the co-production of innovations through interactions with researchers, input suppliers, consumers and others [ 42 ]. Within co-innovation processes, farmers can be involved in jointly identifying problems and co-creating solutions. Thus, the role and identity of the dairy farmer stands to change considerably with the introduction of new technologies; and yet it will not change at all if there is a resistance to the technologies being developed; farmers are a key target for engagement on agricultural technologies.

In understanding how technologies are designed for and adopted on farms, it is useful to consider farmer agency and farmer subjectivities. Studies of farmers’ subjective perceptions of the ‘good farmer’ have been utilized across a growing range of international contexts in order to identify farmers’ cultural scripts, symbolic capital and social norms [ 43 ]. For instance, normative notions of the ‘good’ farmer’, as perceived by farmers themselves, can strongly incorporate productivist ideals within farmer identity [ 44 ]. Research amongst Brazilian dairy farmers [ 38 ] found that profitability, productivity and efficiency were important components of an ideal dairy farm, however quality of life for farmers and workers was also important for this group. It is important to note that farmers’ subjective perceptions of ‘good farming’ does not necessarily align with other stakeholders’ (researchers, policy-makers and consumers) understandings of ‘good farming’. A number of studies have used the lens of the good farmer to investigate farmers’ decision-making processes and engagement with technology adoption related to animal health on dairy farms [ 45 , 46 , 47 ], compact calving [ 48 ] and environmental management [ 49 ]. Other studies have used the concept to understand farmer decision-making processes in switching to dairy farming, including key actors in sourcing information [ 50 , 51 ] as well as to understand the values associated with good farm employment [ 52 ]. Other studies, such as [ 45 ] identified that farmers’ knowledges and values influence their decision-making process.

3. Materials and Methods

The paper is particularly concerned with identifying published academic literature that reports the results of primary research that has been conducted to elicit farmer and consumer-citizen perspectives on dairy farm technologies. (The terms consumer-citizen will be used throughout the paper to refer to consumers, citizens and/or the public unless a more precise term is required and appropriate. Where researchers specifically mention that their research is related to consumers/citizens/public such terms are used.) Relevant literature was identified based on search terms that included adopt*/accept*/attitud*, dairy*, farmer*/consumer*/citizen*, technolog*/innovation*. A preliminary search was conducted in August/September 2021 to provide a framework for the paper. A comprehensive search was conducted in November 2022 to ensure the most up-to-date, relevant published papers were captured. The search was conducted using the library facilities available at University College Dublin, which provides access to wide-ranging databases including Web of Science, ScienceDirect, Taylor Francis Journals, Wiley Online Library, Proquest Science and Technology Databases, CAB Direct and JStor, thus providing access to relevant papers across a wide range of disciplines. Following an initial search, it was decided that for search strings related to consumers/citizens, “farm*” should be included, otherwise literature relating to consumption of dairy alternatives was predominantly identified. Consumer perspectives related to consumption of dairy products or alternative dairy products was not considered to be within scope. Searches were not conducted on specific technologies that have been developed as the authors are not aware of where an exhaustive list of such technologies is available. No time constraint was put on the search. Search strings used include the following:

farmer* AND adopt* AND dairy* AND technolog* OR innovation*

consumer* AND adopt* AND dairy* AND technolog* OR innovation*-

farmer* AND accept* AND dairy* AND technolog* OR innovation*

consumer* AND accept* AND dairy* AND farm* AND technolog* OR innovation*

citizen* AND accept* AND dairy* AND farm* AND technolog* OR innovation*

farmer* AND attitud* AND dairy* AND technolog* OR innovation*

consumer* AND attitud* AND dairy* AND farm* technolog* OR innovation

citizen* AND attitud* AND dairy* AND farm* AND technolog* OR innovation*

Papers that predominantly focused on identifying factors that influence adoption of technologies, measuring the impact of adoption e.g., on productivity or income, all farmers/livestock farmers, elicited the views of experts or stakeholders other than farmers or consumer-citizens, related to technologies such as mobile phone, tablets and computers, related to general thematic areas such as climate change or animal welfare, or were focused on communicating information about production practices were not given detailed attention.

4. Dairy Farming Technologies through the Lens of the Farmer and the Consumer-Citizen

In this section, technologies associated with three key stages of dairy production—breeding, feeding and milking are described, and insights from the literature relating to consumer-citizen and producer perspectives are presented. Previous research has identified that consumer-citizens are concerned with farming practices that they perceive influence affective states of animals, the way that animals are treated and naturalness [ 21 ]. A range of reasons is provided for such concerns, including a perceived relationship between such practices and milk quality, the environment, as well as animal welfare. It is felt that these three stages of production, in addition to covering much of a cow’s lifecycle, provide an opportunity to assess a range of technologies that could evoke such concerns. Table 1 , Table 2 and Table 3 provide details on papers that were identified as having undertaken primary research relating to farmers and/or consumer-citizens’ perspectives on dairy farming technologies at these stages of production. This literature is complemented with additional relevant literature that explains the technology or provides insights on farmer or consumer-citizen perspectives where appropriate. Thus, there is diversity in the nature and variety of literature types contained in each of the three sections, due to different areas of focus in the available literature.

Overview of primary research on consumer-citizen and farmer perspectives on selected on-farm dairy technologies (general and breeding related).

Overview of primary research on consumer-citizen and farmer perspectives on selected on-farm dairy technologies (feeding related).

Overview of primary research on consumer-citizen and farmer perspectives on selected on-farm dairy technologies (milking related).

4.1. Breeding

For decades animal breeding has largely focused on production efficiency, and it is claimed that animal breeding programs have been responsible for approximately half the observed changes in animal performance [ 53 ]. This indicates a high level of industry and farmer adoption and use of technologies produced by breeding programs. A range of reproductive technologies are currently used in dairy production systems, e.g., artificial insemination, embryo transfer, and sexed semen, and a range of hormone treatments are available to aid fertility, or to synchronise oestrus and/or ovulation, and thus calving. These have accompanied the spread of an intensive model of animal husbandry and face different levels of adoption amongst farmers, and knowledge and acceptance is variable amongst consumer-citizens. Ref. [ 54 ] hypothesised that it is likely that few consumers are aware of such reproductive management practices, and even if they were aware that they would likely perceive this type of assisted reproductive techniques to be unnatural and unwelcome.

Research on farmers in Australia, New Zealand and Spain found that farmers’ attitudes towards breeding tools is a multidimensional concept [ 55 ]. Research on Australian dairy farmers found that they view the utility of breeding tools such as Australian Profit Ranking (APR) and Estimated Breeding Value (EBV) quite positively, albeit with some farmers noting that some important traits do not have EBVs and that APR does not weight traits according to their specific needs [ 56 ]. In exploring Danish farmers’ attitudes towards a breeding technology that is not yet implemented (referred to as OPU-IVP-GS technology, combining Ovum Pick Up (OPU) with in-vitro production of embryos (IVP) and genomic selection), ref. [ 57 ] found that 76% of their sample (which contained an approximately equal number of organic and conventional dairy farmers) would be likely to use the technology. Most of the farmers saw the technology as beneficial, however, about 1 in 5 has some ethical reservations. In relation to the latter, increasing the speed of breeding refinement to an unnatural level (15% of the respondents), a belief that fertilization should take place without human interference (18%) and a belief that it could “create monsters” (18%) were reasons given. In keeping with the concept of the “good farmer”, 66% agreed that it is important to keep up with new breeding technologies. It is noteworthy that these farmers considered consumer perspectives as well as farmer perspectives, with 44% fearing that consumers could find the technology ethically problematic and lose trust in dairy farmers/farming. However, a Canadian study of dairy farmers, which found that more farmers agreed with the statement that “routine use of [breeding] synchronisation programs is acceptable to me” than the statement “routine use of synchronisation programs is acceptable to consumers”, led the researchers to conclude that while farmers may have an awareness of a lack of public acceptance for certain technologies, public perception does not have a high influence on farmers’ decisions about reproduction management [ 58 ].

Sexed semen is proposed as a solution to the production of male calves from the dairy herd that are of limited economic value and are associated with low levels of animal welfare [ 59 ]. The term “bobby calf” is used for these calves and it is a focus of many animal rights campaigns. Research in Brazil found that while citizens have a low level of awareness of the practice of culling of newborn male calves, when told about it they reject it outright [ 38 ]. It is also of interest to stakeholders within the sector due to reputational risks. Adoption of sexed semen could mean that 90% of the calves born in a herd are female [Holden and Butler, 2018, cited in [ 59 ]], thus significantly reducing the production of low-value male calves. However, while some citizens actively seek a solution to bobby calves, consumer-citizens are generally not in favor of technologies that are seen to interfere with nature. A survey of German consumers found that most people have a negative perception of advanced reproductive technologies including sexed semen (the majority of consumers disapproved of the following reproductive technologies; sexed semen (53%), embryo transfer (58%), cloning (80%) and hormone treatment to increase fertility (65%)) [ 54 ]. Furthermore, although the technology has been available for a number of years, in many countries adoption rates by farmers have been low due to issues such as low conception rates, low availability and high cost [ 60 ]. Drawing on insights from research conducted with consumers in Brazil, ref. [ 32 ] point out that sexed semen is a high cost technology, making it less accessible to small-scale farmers, availbale online: https://www.foodandlandusecoalition.org/wp-content/uploads/2019/09/FOLU-GrowingBetter-GlobalReport.pdf (accessed on 26 January 2022).

An interesting aspect of reproduction technologies is that use of one of these technologies can enhance adoption of another technology. Given that the issue of surplus calves on dairy farms is exacerbated in countries where dairying is based on seasonal pasture-based systems due to the emphasis of compact calving, sexed semen may be linked to hormone use. This is because achieving a high degree of compact calving is a complex task, sometimes requiring hormone treatments to achieve it, which may be viewed negatively by consumers. The explosive growth in organic milk in the US in the 1990s is attributed to consumer concerns about hormones [ 64 ], and other research in the US reports that consumers prefer natural practices, with the minimum use of hormones [ 2 ]. Interestingly a study by ref. [ 48 ] demonstrated that compact calving was aligned to the ideal of a ‘good farmer’ in a seasonal pasture-based system, with a high rate of compact calving reflecting positively on the farm and the farmer.

Gene editing is a further development in breeding that facilities faster genetic advancement than the more traditional genetic selection techniques. Gene editing is proposed as a means to improve animal health, animal welfare, and production efficiency and to create the potential to produce milk with reduced allergenic potential, through the controlled manipulation of DNA in a single generation [ 32 , 65 ]. In research on Brazilian consumers, it was identified that the acceptability of gene editing in cattle was increased by perceptions of benefits to animals, and influenced by the perceived distribution of benefits [ 32 ]. Some participants in this consumer study in Brazil stated that the premise for accepting gene editing was that the animals should benefit. Interestingly some participants identified economic risks for producers, with benefits accruing to large corporations rather than small scale farmers, while others felt that farmers could take other approaches to achieving the same goal, and in adopting gene editing that they could be in dereliction of their duty to animals. The researchers quote one participant as saying “They don’t want to plant a tree, they want to modify the cattle [for heat resistance] so that they can leave them in the heat, really. They do not want to plant a tree, so they make them [cattle] put up with the sun” (p. 7 of 20). While consumer rejection of practices that are deemed “unnatural” is a consistent theme with the introduction of new food technologies [ 66 ], some researchers conclude that gene editing may contribute to the growing public perception of a loss of naturalness in the system, rather than reflecting concerns regarding the naturalness of the technology per se [ 32 ]. In this way they argue that concerns about intensification of animal production systems may reinforce these problems, and be the “final straw in solidifying their negative views of animal agriculture” (p. 13 of 20). In contrast to this, the researchers conclude that some participants acknowledge the potential of the technology to tackle animal production, health and welfare challenges. They also conclude that there is evidence to suggest that consumer acceptance and willingness to pay for food produced using gene-editing technology specifically tends to increase when socially beneficial attributes are evident rather than when benefits that accrue solely to the producer [ 67 ]. Nonetheless, stakeholders should be aware that acceptance of the technology could be due to resignation rather than trust in the potential of the technology. It has been reported that some participants welcomed gene editing because it was preferable to the status quo [ 32 ], while research across consumers and low-input and organic supply chain members, including farmers, across four European countries “confirms that no interest exists within these sectors for innovations based on biotechnology” (p. 1166). In relation to traditional, genetic and genomic selection, research in Australia, New Zealand and Spain found that farmers’ attitudes towards these had two components: traditional selection on the one hand, and genetic and genomic selection combined on other hand [ 55 ]. They concluded that farmers’ positive attitudes towards traditional selection does not imply a negative attitude toward genetic/genomic selection and vice-versa and that farmers do not differentiate between genetic and genomic selection despite being quite different breeding approaches with their specific uses, strengths and limitations [ 55 ].

Researchers investigated Brazilian farmers’ attitudes to the use of automated behaviour recording and analysis systems (ABRS; i.e., sensor technologies) that could aid oestrus detection, as timely and accurate detection of oestrus is very important for dairy farmers [ 63 ]. They found that farmers face practical difficulties in adopting such technologies (e.g., low quality of internet services (33%)), and had concerns about costs. They also found that the farmers were interested in the technology to improve reproductive rates (25%) and monitor production efficiency (25%). Quality of life factors were also important with the technology associated with enabling them to reduce the number of animals to be checked, and to do so more easily. This paper concluded that “farmers believe that ABRS is improving the farm’s routine and quality of their lives as well as reproductive rates” [ 63 ] (p. 273). Research on Australian dairy farmers’ perspectives on precision technologies indicates that automatic oestrus detection systems are one of the technologies with the highest levels of expected adoption within 10 years (80% of farmers expected increased adoption rates) [ 68 ].

4.2. Feeding

4.2.1. dairy cow feeding.

Breeding and improved management has resulted in increased yields from cows. However, the increased energetic and nutritional requirements of cows has also resulted in a shift towards more nutrient dense diets, including increases in the amount of grains, pulses and maize in their diets [ 69 ]. Thus in many countries, indoor feeding systems such as zero-grazing are increasing while simultaneously the number of grazing dairy cows is declining [ 70 , 71 ]. Grazing is, however, inherently close to the natural behavior of dairy cows [ 34 ] and is viewed favorably by consumer-citizens whose concept of an ideal farm is one that incorporates natural living where animals are provided with access to space and pasture [ 38 ], and are less stressed. In describing an ideal dairy farm, Brazilian citizens state that such a farm has “ adequate pasture and feeding, as natural as possible ” (Citizen 78); “… with extensive rearing, natural pasture, so that animals are not stressed ” (Citizen 115) [ 21 ]. Avoiding the practice of tethering cows is also viewed positively by consumers [ 64 ]. An online engagement study of US and Canadian consumers found that they valued pasture access for cows not only for its benefits in terms of providing grass as a feed to cows; they also cited benefits such as exposure to fresh air, ability to move freely, ability to live in social groups, improved health, and healthier milk products [ 72 ]. Interestingly, this study reported that consumers recognize the importance of adequate protection for animals from adverse climatic conditions and identified a significant cohort of consumers who are neutral on their attitudes to pasture access (approx. 17% in this sample). The neutral cohort identified disadvantages as well as advantages of pasture grazing, with a concern that cows could have poorer health, producers would be less economically efficient, additional land would be required and grazing may not be environmentally beneficial. Of the small number who were not in favor of pasture grazing (3.1%), there was a feeling that confinement systems were good for cows because all their needs were met: “ If cows are happy indoors, there is no need to provide pasture ”. The authors concluded overall that participants view access to pasture as desirable but that they recognize that it may be difficult to achieve on some farms for reasons such as a lack of available land, inappropriate environmental conditions for grazing, and concerns about reduced milk production. Indeed, they reported that consumers showed a willingness to combine a mixture of indoor housing and pasture to accommodate the challenge of implementing grazing-based systems on all farms. Similarly, other research found that German consumers accept indoor housing if access to pasture is also provided [ 73 ]. Dutch citizens additionally value the image of dairy cows grazing on pasture for aesthetic and cultural reasons [ 74 ]. Outdoor systems with grazing animals are perceived not only as more animal welfare friendly by the public but also as more environmentally friendly and more traditional than housed systems [ 75 ]. A quote from a participant in the US/Canadian study illustrates this view: “ Rotational grazing gives high production and the cheapest, most environmentally friendly sunlight harvest and fertilizing/waste removal/treatment ” [ 72 ]. The extent of consumer-citizens knowledge of pasture-based production is however low in some areas, such that some consumers mistakenly believe that all cattle are pasture-fed and confuse such systems with organic and other production systems [ 76 ]. Their awareness of alternatives to pasture based systems is questionable also; only 31% of respondents to a consumer survey in Brazil were aware of the practice of zero-grazing [ 77 ]. Regardless of the low level of awareness of zero-grazing however, respondents were able to assess the practice based on factors relating to naturalness, animal welfare, milk quality, environmental impacts and perceived preeminence of productivity and profit over other food animal production goals. Examples of reasons given by these respondents for favoring pasture-based systems include “… she should be in touch with nature, she is a farm animal ” (R166); Removing something that is natural for an animal is always a step backward in environmental terms ” (R26); “ With dairy cows grazing natural pasture, the milk is healthier and also the cows are more comfortable ” (R34).

From a production perspective, well-managed pasture-based systems are also generally considered to be environmentally and economically sustainable [ 78 ], with many experts valuing pasture grazing “as the most natural, species-appropriate way to keep cattle as it is beneficial both for animal and human health as well as for the environment” [ 71 ] (p. 2). Brazilian dairy farmers noted many benefits to pasture-based systems, associating them with high standards of animal welfare, low costs of production, reduced workload for the farmer and environmental benefits. Quotes from farmers undertaken in this research [ 21 ] include the following “ Shade, water and pasture during the day and night. This is the only way the animals can be free to express their natural behavior ” (Farmer 127) ; I imagine an ideal farm producing milk with low costs of production, which means, pasture based… ” (Farmer 93); “…an ideal dairy farm has pasture based production, because it has less workload… ” (Farmer 92). Indeed, there is evidence that cows are highly motivated to access pasture and as a result several Nordic European countries have implemented regulations that require farms to provide dairy cows with access to pasture for specified periods of time, and organic standards in many parts of the world also regulate access to pasture, at least for part of the year [ 79 ]. However, research has demonstrated negative as well as positive impacts of dairy grazing systems on the environment when compared with intensive indoor systems; for example, soil can be damaged through treading by cattle in grazing systems [ 80 ]. This follows through to more nuanced perspectives amongst different farmer groups. For example, Danish research found that farmers have different views on the impact of grazing on milk yield, with non-grazing farmers associating it with lower yields and seeing this as an obstacle to increased grazing, despite a poor relationship between milk yield per cow and profit [Kristensen et al., 2010, cited in [ 70 ]]. Qualitative research on farmers in Western Canada shows the impact of farm specific aspects on farmers’ attitudes towards outdoor access (as opposed to grazing per se) as well as their personal beliefs and values [ 81 ]. They found that reasons not to provide outdoor access related to five main thematic areas: (1) adverse climate conditions; (2) concerns about cow welfare; (3) concerns about profitability; (4) lack of suitable farm infrastructure; and (5) ease of management with indoor systems. Ironically the reasons given for providing outdoor access directly mirrored these and were (1) conducive local climate; (2) improved cow welfare; (3) improved profitability; (4) suitable farm infrastructure; and (5) ease of management with outdoor access. Different climatic conductions in different Canadian states and different levels of on-farm investment and associated infrastructure were proposed as reasons for different views on the same practice. Qualitative research of farmers who practiced either intensive indoor feeding (IF) or full-time grazing (FG) found that both groups were equally concerned with animal welfare however they saw high animal welfare being provided through different routes: the IF group was mainly concerned with adequately fulfilling animal requirements through feeding concentrates (high-yielding Holstein dairy cows can show energy deficiencies unless their diets are supplemented to a large extent with concentrates [ 82 ]) while the FG group was focused on the positive aspects of grazing on animal welfare [Baur et al., 2010, cited in [ 70 ]]. Overall, there is a recognition that there are constraints to providing pasture, particularly on farms that do not have an adequate land base or on farms whose land base is vulnerable to impacts of grazing cows. Ref. [ 72 ] concluded that producers in their US/Canada study appreciate the benefits of providing access to pasture and that they supported it in principle, but that they felt limited in their ability to do so in practice.

Differences in perspectives on pasture feeding between farmers and consumer-citizens was highlighted in a review [ 70 ]. While they reported that milk with a pasture-fed label resulted in a higher consumer price than milk without a pasture-based label, they reported that the establishment of the German label was difficult because the dairy farmers were concerned that the program would lead to discrimination against all-year housing. Other Willingness to Pay (WTP) studies have reported that such market differentiation can result in a lower WTP for conventional products rather than a premium for differentiated products. Thus, adoption of some innovations that are seen as beneficial by consumers can have a positive impact on some farmer groups but simultaneously they can have a negative impact on other farmer groups.

All systems of production are coming under increased scrutiny regarding greenhouse gas emissions and more notably the production of methane from cows is to the forefront. Dietary characteristics and fermentation conditions in the rumen are factors identified as influencing methane production [ 83 ]. Dietary measures investigated to reduce the methane loss from dairy herds involve the manipulation of the cows diet through the inclusion of additives (e.g., ionophores, organic acids, and plant secondary metabolites (e.g., condensed tannins), oils, red seaweed) as well as improving forage quality and increasing concentrates fed [ 83 , 84 ]. Ref. [ 84 ] stated that the potential use of plant extracts including seaweed are seen as a natural alternative to chemical additives and are well perceived by consumers, however the study did not investigate consumer attitudes towards dietary manipulation. Overall, there appears to be limited research focusing on consumer-citizen perceptions regarding methane reduction strategies of ruminants, with an expectation that they will accept such technologies because the end result is desirable.

This seems to be mirrored in relation to farmer perspectives. While research has been conducted on farmers’ knowledge and attitudes towards climate change, and some research has been conducted on farmers’ preferred mitigation options in the Netherlands, including dietary manipulations involving by-products and increased maize feeding [ 88 ], their attitudes on dietary additives for the purpose of reducing GHGs do not seem to have been investigated. Ref. [ 88 ] concluded that farmers tend to choose mitigation options that are relatively simple and either cost effective or have only relatively small additional costs. This could be the case for feed additives that reduce GHGs but other factors could also be involved. Ref. [ 84 ] stated that farmers will adopt a practice (such as methane reduction strategies) only if there is a positive economic impact on animal production and farm profitability, but there is evidence to suggest that this is not always the case. Investigations of how farmers’ engagement with conservation tillage is shaped by their identity as a good farmer found that while economic capital played an important role in farmers’ decisions to adopt conservation tillage, cultural and social capital were inextricably linked to its development [ 89 ]. Furthermore, the concept of the good farmer embodies the good cow with many studies showing that farmers have an emotional attachment and pride in their cows [ 90 ]. Research investigating Swedish farmers’ perspective of antibiotic use found that the farmers interviewed had a sense of responsibility for their cows, which was central to their farm management, and is an important factor determining agricultural practice [ 46 ]. These factors could also be at play in relation to methane abatement strategies. However, there seems to be a knowledge gap in this area.

4.2.2. Dairy Calf Feeding

Separation of the cow and calf immediately or shortly after birth is routinely practiced on dairy farms [ 9 , 34 ]. It is however the focus of increased interest among the public because of calf welfare concerns, with high profile campaigns by animal welfare groups targeting this practice. Consumer-citizens who object to the practice believe that early contact is important for both the cow and calf, that it is natural and that separation is unethical. Brazilian consumers made the following statements in respect of the practice “ Contact with the mother is essential for all species ” (R398); “ It is not right to separate cows from their young just to increase milk production ” (R216) “ I believe that the stimulus generated by the calf suckling and the emotional connection between them are beneficial for both the quality of the product and the health of the animals ” (R383) [ 77 ]. Similar sentiments were expressed by the public in research conducted in North-America/Canada with a view amongst supporters stating that the industry can and should accommodate cow-calf pairs [ 9 ]. Despite this interest, researchers found that urban Brazilians were generally unaware of this practice (33% of their sample was unaware of the practice) [ 77 ], and a study in North America/Canada found a lack of consensus regarding acceptance of this practice; they found 44%, 48% and 9% of their respondents chose “yes”, “no” and “neutral” respectively to the question “Should dairy calves be separated from the cow within the first few hours after birth?” [ 9 ]. Research in the US and Germany [ 13 ] also found a lack of consensus on the topic; they identified three segments labelled “Late”, “Unsure” and “Early” referring to the preferred time of separation, and found consumers from both countries in each cluster. This could be explained by Dutch research; these authors highlight a tension felt by consumers between modernity and naturality in relation to the separation of the calf and cow and calves being fed with milk replacer rather than their mothers’ milk. They cite a quote from a Dutch consumer from earlier work [ 4 ] “ Production comes first. I understand that a farm has to function like a business and that the milk production needs to be as high as possible. But I feel a bit of resentment too. Because what is best for the animals? As humans, where are we going ?’ Research in the US and Germany found national differences in preferences; they found German consumers were generally more in favour of later separation (69% of the sample) compared to US consumers (55% of the sample) based on initial questioning [ 13 ]. The researchers speculated that these differences may be a consequence of differences in values, which are influenced by cultural norms within societies. Interestingly they also found that when consumers in both countries were presented with 22 different arguments for and against early and late separation, there was a decline in the numbers favouring early separation, an increase in the unsure responses and a decline in the responses at the extreme end of the scale for later separation. Consumer cited responses in favour of early cow-calf separation include welfare benefits in research undertaken in the US and Canada “ I think farmers should separate the calves from the mothers not only for the calves’ safety but so the mother can rest ” (P930-CR) [ 17 ].

Research has reported that consumers see farmers as being at the center of such dilemmas, and as having a responsibility to “handle these dilemmas, resolve the conflicts and maintain a desired balance between modernity, tradition and naturality” [ 4 ] (p. 1461). There has been increased interest in extended cow-calf contact by the farming population as well as researchers and advisors, but while some European farmers provide extended cow-calf contact [ 34 ] dairy farmers were found not to be favorably disposed to it in research conducted in six European countries [ 85 ] and Brazilian farmers have concerns regarding animal welfare, labor, and the suitability of the dairy system for providing extended cow-calf contact [ 77 ]. Farmers in New Zealand had similar concerns relating to (1) poor animal welfare for both cow and calf (relating to mastitis in the cow, inadequate colostrum for the calves, lack of shelter for calves while outdoors with cows and increased stress to both due to delayed separation); (2) increased labor and stress on staff; and (3) requirement for system level changes, relating to infrastructure and herd management [ 34 ]. Some illustrative quotes from this research include: “ The reason I don’t do it [keep cows and calves together] is the failure rate of calves not feeding off their mothers. And the importance of them getting the colostrum within the first few hours ” (C-53); If the cows and calves are together and you get bad weather, there is no shelter for them. When you take them off, at least they are getting fed twice a day ” (C-16); Once they get that bond, it is hard to keep the cows in [the paddock] , I think the cow is under stress for longer, and she bellows all day and night ” (C-15); If it is going to take twice as long as what you are already going, then there has got to be some pretty decent benefits ” 9C-44; “We are all on time restrictions and I think often what could be better for the animal could be quite detrimental to the farmer by way of mental health and added pressure ” (C-33); “ Under health and safety you couldn’t do it [keep cows and calves together]. I would knowingly put my staff in harm …[if I did that]… Cows get more protective. You couldn’t do it with a clear conscience (C-7). Similar to pasture-based production systems, while some of these farmers were theoretically in favor of extended cow-calf contact, they cite practical barriers to implementation. Condensed, seasonal calving patterns, associated with pasture-based dairy systems, are the root of many of these concerns. Echoing issues raised with AMS systems below, farmers note that changing the cow-calf system would require substantial system change rather than merely changes to the calf-rearing process “ I would have to change the yard management, grazing management, insemination times, bull management, and also the surviving of calves will be a little bit less. ” (C-41). A fundamental objection however to prolonging cow-calf contact related to farmers’ fundamental views of their role as farmers; many see their role as relating to milk production as opposed to rearing calves. “ We are about producing milk. That is why we wouldn’t leave them on for longer ” (C-17). Interestingly, in contrast to this, lack of confidence in the mothering ability of the cow was another reason for early calf removal, with some farmers citing breeding as a cause of this; “ I’m not saying that it has been done deliberately, but if you look at the mothering ability of cows today compared to the cows that were bred 30 years ago, you would find the mothering ability has been quietly eroded ” (C-27). These farmers also recognized that different systems may be appropriate in different contexts and see the wider context of dairy farming “ It is more area-specific the way you can do things. What we can do on the west coast [is different from what farmers in other areas can do]… It can even be farm-specific, not always area-specific ” (C-25). Many of these concerns were refuted by a small number of farmers who practice cow-calf contact, notwithstanding agreement about the need for additional infrastructure and changes within the wider system for successful adoption.

The high labor requirement for calf rearing, particularly on seasonal calving farms, has resulted in increased interest in using technology and automation to reduce the labor requirement associated with calf rearing. Automatic calf feeding systems are increasing in popularity primarily due to claimed economic gains arising from labor savings [ 91 ]. Increased feeding frequency, gradual weaning and socialization benefits for the calf [ 92 ] means that automated feeding can come closer to mimicking the way calves feed and behave in nature, potentially increasing animal welfare. Although there is the potential for increased illness with automatic calf feeding systems if not managed correctly (e.g., due to increased production of urine and faeces), farmers in England have identified one of the benefits of the use of automated milk feeders as alerting them early on to signs of calf illness—such as slow drinking or lower feed consumption [ 86 ], however the research did not specifically address this technology. Nonetheless, the research provided additional insights on their perspectives regarding calf housing systems. It found that farmers used a variety of group sizes (including individual housing early on) when housing calves, with variation largely dependent on the space available to rear calves and the labor-intensiveness of different systems. Individual hutches were considered particularly demanding, but worth the extra labor for improved calf health. Moreover, insights can be gained from other research. The standards of ‘good farming’ are embodied in livestock or the ‘good cow’ [ 90 ]. Therefore, essential to achieving the ‘good cow’ is ensuring excellent care and management of calves from birth through good stockmanship. In addition to the traditional stockmanship skills required to rear calves, the adoption of automatic calf feeders will require the development of new skills and knowledge by the farmer. It will require the farmer to be competent in data collection and interpretation to compensate for the reduced direct contact with calves in order to produce a ‘good calf’. In a study investigating producers’ perspectives on neonatal care of calves, farmers were intrinsically motivated to provide good calf care by their sense of pride and morality, by social obligation to other dairy-industry stakeholders, and sometimes by the economic benefits for their herd [ 93 ]. Although ref. [ 94 ] concluded that participants in their study did value their calves, they noted that some producers did not highly prioritize calf health and productivity outcomes. This could be due to a lack of resources including inadequate facilities, a lack of clarity about calf care as well the time and effort necessary to care for newborn calves [ 93 ]. Therefore, when implemented correctly automatic calf feeders could allow farmers to improve overall calf care thereby increasing productivity. However, there is a lack of research regarding the opinions and perspectives of farmers on automatic calf feeders as well as data quantifying the actual uptake of the technology.

While there does not appear to be any research on consumer-citizen perspectives on automatic calf rearing systems, a study in the US found that group housing of calves was preferred, followed by pair housing with individual housing least preferred [ 87 ]. Reasons cited related to increased socialization (“the calves can play and socialize which is important to all animals ” (PY427)) and space allowance. Of the small numbers who preferred individual housing, calf health (“ best for controlling diseases and nutrition intake ” (PA1124)) and having their own private space were provided as reasons. Furthermore, consumer-citizen perspectives can be anticipated from other research. Although much of the public is unaware that cows and calves are separated shortly after birth, when presented with the information, the main objection is its unnaturalness [ 9 , 95 ]. The definition of naturalness is shifting according to some research, and while the older generations of the public may consider technological solutions to be a further deviation from naturalness and a departure from dairy farming’s agrarian roots, the definition of “naturalness” for younger generations may well have expanded to include technology [ 96 ]. In that regard, the adoption of automatic calf feeders, which allows for autonomy and some similarity to natural behavior, while simultaneously improving individualized care, could improve public perception of calf rearing systems. In this way, it may serve to counteract a misalignment of the needs of the public with the needs of the farmer [ 96 ]. This, however, has not been subject to empirical research.

4.3. Milking

The herringbone and rotary parlors are early examples of technological advances designed and led by farmers, which enabled the expansion of dairy farming. This expansion was seen by many as necessary to increase and stabilize food production [ 97 ]. The change from hand to machine milking provides a historical context for automatic milking systems (AMS, or robotic milking machines) and the same concerns that arose then are seen to persist today with the introduction of AMS [ 98 ]. Dutch research, however, finds that “the entire practice of dairy farming has been reorganized around this device” [ 99 ] (p. 3). This sentiment is echoed in research with Norwegian dairy farmers in which some of them see the technology as implying a completely new way of working, requiring them to be more proactive in relation to animal health and hygiene, using the data provided as a management tool, and focusing on both herd averages and individual cows in managing performance [ 100 ].

The first commercial AMS emerged in the early 1990’s in the Netherlands and since then they have been adopted at an increasing but variable rate in many countries including across Europe, North America, Australia and New Zealand [ 99 ]. Initially AMS was more commonly operated in intensive indoor feeding barn systems where cows have limited access to grass but since 2001, they have been incorporated into pasture-based systems worldwide [ 101 ]. These systems were established as fixed milking parlors but mobile milking systems (MMS) are also available, enabling them to be used in free-range or rotational grassland systems [ 102 ]. In Europe and the US, the majority of AMS are used on small and mid-size farms (<500 cows) [ 103 , 104 , 105 ]), possibly to avoid or reduce the need to hire non-family labor and/or to increase productivity without increasing labor input [ 104 ]. AMS are, in part, a response to some of the issues associated with conventional milking such as health, welfare and labor [ 98 ]. Despite high costs, AMS are increasingly popular amongst farmers for labor-saving and lifestyle benefits, including more time for family and recreation [ 106 , 107 ]. Increased flexibility, as opposed to time gained, was identified as a key benefit of the technology [ 99 ], with farmers in Norway reporting flexibility as more important than labor saving [ 100 ]. However some farmers found that AMS provided less flexibility than expected, because of the need to be constantly on-call [ 98 , 100 , 107 ]. Research on Norwegian dairy farmers indicates that while flexibility is the greatest advantage of AMS, allowing farmers to spend more time with family and friends, and to get more sleep, they acknowledge that flexibility can come at a price and that it also comes with responsibility [ 100 ]. The researchers quoted a Norwegian farmer as saying “ Farmers who consider investing in a robot often ask me: How much time do you need in the cowshed? I answer: As long as possible…You get more flexibility, but its freedom with responsibility ” (p. 114). Ref. [ 98 ] (p. 131) state that claims regarding the benefits of AMS, to both the farmer and the cow, are “certainly contested”. The finding that Australian farmers expect lower levels of adoption of AMS compared to service providers (60% vs. 79% respectively) supports this view [ 66 ]. On the positive side, research with Norwegian dairy farmers supports a view that the data provided by AMS makes farming more interesting. A Norwegian farmer is quoted as saying “ Robotic milking has definitely made farming more interesting. You get a lot of information about each cow…it’s really a good management tool ” [ 100 ] (p. 113). The researchers also note, however, that farmers are selective about the data used and that some find it difficult to utilize all the data provided. Adoption is also associated with being progressive by these farmers; “ To keep up the interest as a farmer something new much take place on the farm from time to time…you have to develop the farm, you can’t just stand still ” [ 100 ] (p. 114). This research also reported on how farmers “domesticated” the technology, addressing challenges relating to being constantly on call, and illustrating the dynamic processes involved in successful innovation.

The milking process of AMS is promoted as a fully automated and voluntary process with no set defined milking times [ 108 ]. In this way it is presented as allowing cows to engage in natural behavior. Instead of human handlers herding cows to the milking systems two or three times a day, cows are incentivized to enter the stall of the AMS unit when they want to by the provision of feed on entry. Relative to conventional milking systems, the milking process in AMS is consistent and the milking routines are predictable for the cows, which is a prerequisite for successful milking [ 109 ]. The flexible and the voluntary nature of the AMS should be conducive to the societal demands of improving animal welfare. Ref. [ 99 ] in reporting on farmers’ interviews in professional magazines, confirm that farmers are convinced that a robot approximates a natural situation. However, there are questions about how AMS influences cow welfare [ 110 ], with challenges identified in relation to udder health, lameness and disruption of the natural behavior of cows [ 109 , 111 , 112 ]. Moreover, while the technology is presented as a voluntary system, designed to give cows freedom and autonomy and enable the expression of more natural behavior by cows, it has been argued that “cows’ bodies, movements and subjectivities are trained and manipulated in accordance with a persistent discourse of agricultural productivism…[…] and technological interventions [specifically robotic milkers] […] contribute to a re-capturing and re-enclosure of bovine life which counters the liberatory discourses which are used to promote robotic milking” [ 110 ] (p. 131). Cows are herd animals preferring to perform their activities, such as eating and resting, synchronously but AMS requires that these tasks are performed individually, which could disrupt the natural behavior of cows [ 109 , 112 ]. Ref. [ 111 ] highlighted that although the milking process is automated, the role of a competent stockperson has not diminished and is vitally important in ensuring that animal welfare is not compromised. European consumers have previously been found to be concerned that increased robotization on farms could lead to the traditional farmer role being replaced by machines, with less human attention directed towards animals and thus, negative welfare consequences [ 35 ]. However, using the Ethical Matrix as a guiding framework, it was found that UK consumers considered AMS largely acceptable, although they were concerned with animal welfare [ 113 ].

The development of AMS can be seen as a shift in the concept of good farming from caring for the animals to allowing the animals to take good care of themselves [ 99 , 109 , 116 ]. This change in cow agency and subjectivity tends to suggest a sort of automation of human activity too [ 98 ]. Indeed, it is suggested that both bovine and human agency and subjectivity are entrained and reconfigured with the use of AMS technology [ 98 ]. Ref. [ 110 ] established that the adoption of AMS technology results in a renegotiation of the established ethical relations on a dairy farm due to the change in the corporeal relationship between cows and humans. The authors suggest that AMS redefines the notion of care in dairy farming, thus changing the understanding of what constitutes a ‘good farmer’ or ‘good stockmanship’. Similarly, researchers suggest that the professional identity of farming is changed from manual labor to an office-based job with the adoption of AMS technology [ 99 ]. In conventional milking systems, good stockmanship can be as seen as the knowledge and skills that evolve from prolonged contact with animals during milking whereas with AMS there is less direct contact with animals and instead the farmer is more reliant on technology and data to identify problems [ 95 , 109 , 116 ]. In that regard, AMS technology creates a shift in identity as farmers are expected to become skilled and knowledgeable in the use of data collection and interpretation while combining it with traditional stockmanship skills to produce a better farming system [ 98 ]. A ‘good AMS farmer’ is therefore defined as one that combines the traditional stockmanship skills with data collection and interpretation skills [ 98 , 99 ]. In this way, AMS does not replace traditional stock keeping skills, rather AMS can enhance stock keeping but this is dependent on the extent to which the stock-keeper is able to adapt their behavior through changes in transformed dairying practices [ 18 ]. Ref. [ 18 ] suggest that where the stock-keeper is able to adapt to the AMS, the hybrid capital of humans, animals and technology can be successfully invested to improve productivity and herd health and welfare, and to enhance human quality of life. With farmers themselves placing increased emphasis on work-life balance, AMS can provide an alternative when labor is unavailable (the absence of a successor or hired workers) or provide a way of continuing to farm after a certain age at which manual labor becomes more of a strain [ 99 ].

Research on UK consumer perspectives on AMS found that 60% of the consumers in their sample believed that AMS use would benefit farmers [ 113 ]. However, while 25% believed that the technology would benefit cows, 50% expected cow welfare to be reduced. When asked about impacts on safety of milk for consumers, 20% believed it would improve safety of milk for consumers, 43% expected no change and 25% expected it to be reduced. Approximately 10% of consumers gave “don’t know” as a response in relation to each of these issues. Given the wider systemic changes, as well as changes in the farmer-animal interface expected above, there seems to be a gap in relation to understanding nuanced consumer-citizen perspectives on AMS.

5. Discussion

Many new technologies and innovations have been introduced to the dairy sector over the years, and more will be required in the future to ensure that dairy production is part of a sustainable food system. It is clear however that successful introduction of such innovations on a widespread basis will not be easy. The problem of technology adoption has for decades been addressed in the social science and extension literature, traditionally with a focus on ‘barriers’ such as knowledge deficits and cultural preferences and, more recently, focused on the importance of recognizing ‘adopters’ as co-designers of technology, with valuable knowledges and end-user insights for the design process. The successful introductions of innovations on a widespread basis is further complicated because sustainability encompasses economic, environmental and social aspects, the simultaneous fulfilment of which can involve trade-offs. Furthermore, more specific to dairy farming, it is accurately explained by [ 4 ] that “the (sociocultural) sustainable development of livestock farming is not an objective concept, but [one] that it is socially and culturally constructed by people in specific contexts”. Moreover, how individuals across different actor groups perceive and evaluate technologies is socially constructed and shaped by beliefs and expectations [ 117 ]. This, in turn, as is evident in the review presented in this paper, means that different actors are likely to have different perspectives on both problems and proposed solutions, and that these are likely to change over time.

This review has found that a wide range of authors have employed diverse methods to assess consumer-citizen and farmers’ perspectives on a range of dairy technologies. Notwithstanding the fragmented nature of this research, and the limitations of the methods used, it found that in addition to expected differences in perspectives between the two actor groups, there are diverse perspectives within each group, as well as areas of agreement between the groups. Moreover, considering the consumer-citizen perspective, it is clear, as has been reported elsewhere [ 118 ] that consumer and citizen perspectives can cause internal tensions within individuals. A potential conflict is illustrated in the case of sexed semen above: as a ‘citizen’ an individual may support the technology due to its potential to mitigate animal welfare issues associated with surplus calves; however, as a ‘consumer’, there can be an aversion to reproductive technologies and a distrust of biotechnology in general. While some researchers [ 13 ] expect citizen perceptions to be more diverse than farmer perceptions, it is clear that farmers are not a homogenous group either, and, additionally, they can occupy other roles alongside the role of farmer, including vets, farm advisors, and input suppliers. In a similar way to the cognitive dissonance seen in relation to consumer-citizen perspectives, this can lead to internal conflicts between the farmer as a “professional” or “expert” and as a “practitioner”.

The OECD [ 31 ] in the context of developing policies for livestock systems, state “scientific facts, including from independent advisory groups, play an important role but are not always widely accepted by the public or stakeholder”. The deficit model approach which viewed a lack of knowledge as the primary barrier to public acceptance of technologies is now considered an outdated model, replaced by years of sociological and psychological studies demonstrating how different actors’ perceptions of risks and benefits of new technologies are shaped by a myriad of values, experiences and beliefs [ 119 ]. Research cited in the preceding sections shows that citizen-consumers assess technologies across a range of dimensions, and that they can consider both positive and negative impacts simultaneously. It is also clear that many consumers can understand the importance of context in considering what is sustainable, with some acceptance of farm-specific solutions. This was particularly evident in the section on dairy cow feeding above. Furthermore, they can have a nuanced understanding of the issues, for example opposing a single-minded focus on animal health at the expense of natural living [ 120 ]. Ref. [ 64 ] however highlighted that consumers have complex and conflicting motivations when making ethics-related food decisions, and consumers may simultaneously define sustainability in conflicting ways or desire conflicting ideals, such as valuing both technological advances and undisturbed nature/naturalness in an agricultural system [ 74 ]. This suggests that consumer-citizen perspectives on individual technologies should be assessed in a wider decision-making context within which consumers engage.

Some similar issues are evident when considering producers’ perspectives with tensions as well as areas of agreement evident with this cohort. Different groups of farmers have different perspectives based on farm and farmer-specific characteristics (e.g., those who feed cows indoors and those who provide access to pastures) and interestingly even where their views on what might be desirable are similar in principle, this may not be consistent with what they do on their own farms for a range of legitimate and practical reasons. This is illustrated in the case of pasture feeding above, with economic factors and land access being significant factors hindering implementation of what might be generally considered a desirable practice.

Fear of industrialization of farming with the introduction of technology and innovation is a recurrent theme in the consumer-citizen literature. The literature cited here suggests that views on what industrialization means in the context of dairy can evolve over time, with some newer technologies being viewed as potentially more “natural” than the technologies that they are replacing. This is illustrated in the section on automatic calf feeding above. However, in general, consumers have been found to be concerned by the concept of robots and machines replacing the traditional role of the farmer. Rather than seeing technology as a data-driven decision tool used by farmers, consumers tend to view the two as being in competition and the expected impact in terms of diminished power/agency of the farmer is a concern [ 35 ]. Thus, societal trust in farming technology, and the perceived transformational role it could have for food production systems, remains a key challenge These concerns, along with the link consumer-citizens make between on farm practices, animal welfare, product quality and human health, and to a lesser extent to environmental impacts, indicate the value of including such actors in anticipatory roles in designing and implementing innovations for a sustainable food system.

When considering farmer and consumer-citizen perspectives simultaneously, it is clear that there are some tensions between the groups. However, we also identified areas of agreement. Noting both tensions and areas of agreement is important for designing and implementing strategies, technologies and shared practices that are responsive and inclusive—“understanding broad areas of social consensus, as well as disagreement, will help to identify methods of bringing industry practices better in line with public expectations” [ 72 ]. Moreover, both groups similarly experience conflicts within the context of their own value systems and contradictory expectations where the development of smart farming is concerned. This is to be expected considering the experimental nature of technological development and the way in which innovation inevitably challenges existing values, perceptions, beliefs and preferences, etc. As explained by [ 4 ], “tensions [exist…] between modernity, traditions and naturality—‘the MTN knot’—each of which has positive and negative faces”. Interestingly, it was reported that Dutch consumers valued the agricultural system in the Netherlands as it combined “apparently contradicting aspects such as technology and nature within one system” [ 74 ] (p. 32). However, as noted by ref. [ 2 ] and concluded by ref. [ 4 ], the general public ‘wants it all’: they prefer naturalness and tradition, but also value modernity in dairy production. While disruption and transformation in agriculture in the past was focused on modernization and industrialization, it is clear from the perspectives reviewed in this paper that technological-driven changes in the dairy sector will also have to embrace “returns to the past”, and give due respect to “naturalness”, principals deemed important by key actors in the value chain.

Overall, the results raise two questions with respect to diverse actor perspectives: (1) can such differences in perspectives be addressed and (2) should such differences be addressed? Answering these questions requires an understanding of the causes of the differences in addition to the identification of the differences. The OECD [ 31 ] identified three sources of friction in decision-making processes involving different stakeholders, differences relating to knowledge, interests and expectations, and values and some researchers [ 13 ] agree that differences in knowledge and a lack of shared values contribute to differences in opinions between consumer-citizens and those involved in livestock production. Where they arise due to differences in knowledge, some researchers propose that efforts should be put into educating the public so that can they better understand the nature of farm practices and the reasons for their use on farms [ 54 , 77 ]. Concepts such as edu-tainment and edu-tourism have been promoted in this context [ 121 ]. This is based on an assumption that most consumers have limited knowledge and experience relating to agriculture, and thus that exposing them to farms can give them a realistic impression about what farming actually entails [ 74 ]. This assumption is verified by research that identified a disconnection between consumer expectations towards mountain production systems and reality [ 122 ]; when conducting research on how consumers perceive products from traditional mountain dairy farms they found that appreciation of certain husbandry and management choices did not translate into a recognition of what they looked like when images of traditional husbandry systems were provided. However, in relation to resolving concerns about a complex issue such as animal welfare, it has been argued that relying on public education is not likely to be very effective because of the low ratio of “naïve public to industry insiders” [ 12 ]. Moreover, as found by research on US and German consumers [ 13 ], clusters with different perspectives attend to different types of information and arguments, often selecting information to support initial positions, and reflecting people’s moral intuition. Furthermore, views about such perceptions are formed based on prior experiences and values, as much as knowledge and facts. Thus educational efforts, which often are included in government policies, are unlikely to consistently result in the desired effects, heading off criticisms about animal production practices, when differences in values rather than ignorance is the cause of difference [ 13 , 123 ]. It is interesting to note that educating farmers is generally focused on providing them with technical expertise, with a limited focus on social learning whereby farmers could obtain a better understanding of what is required by the market and society. The concepts of edu-tainment and edu-tourism could thus be considered for their role in educating farmers as well as the public, potentially contributing to further alignment in perspectives. Differences relating to knowledge can also relate to a lack of agreement on what the facts are and what the evidence provided by science means. It also assumes that scientific information is unbiased and that science-based information is the only source the public should use to assess agriculture. Some researchers argue for greater transparency and communication, rather than education per se, as they believe that when consumers are kept unaware of dairy industry practices, the potential for miscommunications and misunderstandings surrounding sustainable dairy grows [ 124 ]. They caution that such initiatives need to be well-planned, founded on an understanding of consumer expectations regarding sustainability practices, and supported by evidence; “greenwashing” or other misrepresentations of sustainability efforts can easily lead to consumer backlash. Aligned with the principles set out by RRI [ 27 ], any government policy interventions should consider the consequences—positive, negative or unintended—an intervention could have [ 125 ]. One manner of doing this is to lever inclusion and participatory exercises, which incorporate consumer-citizens and farmers so as to ensure their diverse values and needs are reflected in policy development.

Where groups have diverging interests, representative groups come to the fore. These can be legitimate advocacy groups (e.g., civil society organisations in the case of animal welfare) or influence-seeking interest groups who pursue their special interests ahead of public interests (e.g., representative bodies that look to expand dairy production without taking account of climate impacts). Diverging interests can be addressed through inclusive and transparent decision-making processes. Unaligned interests can be addressed also through providing some compensation to those who are negatively affected. Where farmers incur extra costs in adopting technologies that can have a negative impact on performance but a positive impact on the environment, e.g., as may be the case of methane reduction strategies, policy instruments can, and arguably should, compensate farmers for subsuming their financial interests in favor of public good.

Addressing differences in values is more challenging. However, where shared values exist, there are significant opportunities to implement practices that are seen as desirable by a range of actors. Shared values amongst companies, governments and social organizations relating to grazing and the benefits of it, resulted in the establishment of the Grazing Agreement in the Netherlands in 2012. This initiative, involving a contract among more than 80 organizations (companies, governments, and social organizations) to promote grazing practices, is credited with 82% of dairy farms in the Netherlands practicing grazing in 2018. In addition to financial incentives for primary producers, research, education and extension are important components of the program. These are also important for government policies, which often focus on financial incentives, and acknowledge that top-down regulatory interventions (such as regulation, incentives or punishment) need to be accompanied by bottom-up interventions that tackle the motivation, values and capability of individuals to engage with new technologies and practices [ 126 ]. Where values are not shared, differences can still be reconciled. This can be achieved through creative thinking to find specific actions that can be supported by people with different values. This requires high levels of engagement, and deliberative approaches can help to build societal consensus, or at least to clarify issues. In complex cases, this can involve a series of multi-stakeholder consultative processes [ 31 ].

Differences in perspective between and within groups is not in itself problematic. Indeed, “tensions between diverging interests (and hence interest groups) are unavoidable in diverse and pluralist societies, and much of political decision-making involves a search for compromises or grand bargains which can reconcile diverging interests in society” [ 31 ]. Indeed, diverse perspectives can result in better solutions through challenging assumptions. However, differences can be problematic, and need to be addressed, if one interest group has a disproportionate influence over decision-making and if certain groups are not included. Moreover, it is important to recognize that the responsibility for developing sustainable food systems is not vested in one actor; rather it is allocated jointly between farmers, policy makers, regulators, different actors in the food chain, consumer-citizens, etc. [ 11 , 127 ]. Thus, it is not a matter of blindly agreeing to do what one group wants or expects; some minimum level of consensus is required to progress. Without this, innovations and technologies that neither fit the farming context nor meet consumer needs could be developed. In addition, it could also result in an “unfunded mandate” whereby producers are required to adopt practices that result in additional costs to them without any extra return. Such an approach is therefore unlikely to be economically or socially sustainable. Arguing for solutions between farmers and non-farmers in agricultural governance, ref. [ 128 ] discusses the need to recognize a “shared fate, interdependence, and mutual responsibility”. The inclusion of all perspectives (encompassing knowledge, expectations and values as well as attitudes and behaviors), and as highlighted in this paper specifically, the inclusion of farmer-consumer/citizen perspectives, is essential in decision-making process regarding technology and innovations in the dairy sector, with responsiveness necessitating acknowledging differences while striving to find common ground.

Inclusion however should not be viewed as a quick-fix or a panacea for consumer resistance or farmer non-adoption of different technologies. It should be viewed as a mindset and a commitment to ‘doing’ research and innovation differently. Increasing the inclusiveness of the innovation process will ensure a more fair, balanced and multi-dimensional approach to the development and implementation of technologies and innovations on farm. Given the agricultural production system impacts of some technologies (e.g., automatic milking systems), as well as wider food systems impacts (e.g., in relation to the roles and identities of farmers, product quality), this wider approach will be essential to helping to identify and address unforeseen and unintended consequences. At the same time, inclusion must be carefully managed. Inclusion “is not a prerequisite to success; as well as being time consuming, this may create uncertainty if roles and objectives are not clear from the outset” [ 22 ]. Social sciences can support the careful management of this process of engaging and bringing diverse stakeholders such as farmers and consumer-citizens into the inner circle of innovation and research. Moreover, due to their expertise in the methodologies that support co-design processes, social sciences have a key role to play in facilitating inclusive innovation to support responsiveness in the dairy sector [ 127 ]. Overall, while agreeing with calls [ 4 ] for ongoing collaboration between social and animal scientists in order to develop livestock farming systems that are more socio-culturally sustainable, we call for a concerted effort to ensure anticipation, inclusion, reflexivity and responsiveness in developing innovations for the dairy sector of the future.

6. Conclusions

Innovation has always been a risky process. As society places greater demands on dairy production systems to produce a range of goods and services beyond basic food products, and as researchers and their funding bodies recognize the need to embed principles of responsible research and innovation, identifying, understanding and taking account of (to some extent at least) the perspectives of diverse stakeholders will become increasingly important. As this review highlighted, these stakeholders have both similar and divergent perspectives, so this will not be an easy process. Moreover, while consumer-citizens can be easily involved as research subjects, and vocal civil society organizations exist to engage on some issues (e.g., animal welfare), unlike farmers who have representative bodies, the route through which consumer-citizens can be actively involved is not so clear. Deliberate and concerted efforts on the part of policy makers, research funding bodies, dairy sector organizations or others is required.

Author Contributions

Conceptualization: All authors; Investigation: All authors; Methodology: M.M.H.; Writing—Original draft preparation: Section 1 , M.M.H., Section 2 , Á.R. and Á.M., Section 3 , M.M.H. and M.B., Section 4 , M.M.H.; Writing—Reviewing and Editing, All, Supervision; M.M.H. All authors have read and agreed to the published version of the manuscript.

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Data availability statement, conflicts of interest.

The authors declare no conflict of interest.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

• 1. Hirst K.K. Dairy Farming: The Ancient History of Producing Milk. [(accessed on 11 December 2021)]. Available online: https://www.thoughtco.com/dairy-farming-ancient-history-171199 .
• 2. Cardoso C.S., Hötzel M.J., Weary D.M., Robbins J.A., von Keyserlingk M.A.G. Imagining the ideal dairy farm. J. Dairy Sci. 2016;99:1663–1671. doi: 10.3168/jds.2015-9925. [ DOI ] [ PubMed ] [ Google Scholar ]
• 3. Danne M., Musshoff O. Analysis of farmers’ willingness to participate in pasture grazing programs: Results from a discrete choice experiment with German dairy farmers. J. Dairy Sci. 2017;100:7569–7580. doi: 10.3168/jds.2017-12756. [ DOI ] [ PubMed ] [ Google Scholar ]
• 4. Boogaard B.K., Oosting S.J., Bock B.B., Wiskerke J.S.C. The sociocultural sustainability of livestock farming: An inquiry into social perceptions of dairy farming. Animals. 2011;5:1458–1466. doi: 10.1017/S1751731111000371. [ DOI ] [ PubMed ] [ Google Scholar ]
• 5. Britt J.H., Cushman R.A., Dechow C.D., Dobson H., Humblot P., Hutjens M.F., Jones G.A., Ruegg P.S., Sheldon I.M., Stevenson J.S. Invited review: Learning from the future—A vision for dairy farms and cows in 2067. J. Dairy Sci. 2018;101:3722–3741. doi: 10.3168/jds.2017-14025. [ DOI ] [ PubMed ] [ Google Scholar ]
• 6. Capper J.L., Cady R.A., Bauman D.E. The environmental impact of dairy production: 1944 compared with 2007. J. Anim. Sci. 2009;87:2160–2167. doi: 10.2527/jas.2009-1781. [ DOI ] [ PubMed ] [ Google Scholar ]
• 7. Brombin A., Pezzuolo A., Brščić M. Are we ready for the big change in the dairy production system? Res. Vet. Sci. 2019;126:17–19. doi: 10.1016/j.rvsc.2019.08.006. [ DOI ] [ PubMed ] [ Google Scholar ]
• 8. Garnett T., Appleby M.C., Balmford A., Bateman I.J., Benton T.G., Bloomer P., Burlingame B., Dawkins M., Dolan L., Fraser D. Sustainable intensification in agriculture: Premises and policies. Science. 2013;341:33–34. doi: 10.1126/science.1234485. [ DOI ] [ PubMed ] [ Google Scholar ]
• 9. Ventura B.A., Von Keyserlingk M.A.G., Schuppli C.A., Weary D.M. Views on contentious practices in dairy farming: The case of early cow-calf separation. J. Dairy Sci. 2013;96:6105–6116. doi: 10.3168/jds.2012-6040. [ DOI ] [ PubMed ] [ Google Scholar ]
• 10. Regan Á., Kenny U., Macken-Walsh Á. What does the public want to know about farming? Findings from a farmer-initiated public consultation exercise in Ireland. Sustainability. 2022. under review.
• 11. Frewer L.J., Kole A., Van De Kroon S.M.A., De Lauwere C. Consumer attitudes towards the development of animal-friendly husbandry systems. J. Agric. Environ. Ethics. 2005;18:345–367. doi: 10.1007/s10806-005-1489-2. [ DOI ] [ Google Scholar ]
• 12. Weary D.M., Von Keyserlingk M.A.G. Public concerns about dairy-cow welfare: How should the industry respond? Anim. Prod. Sci. 2017;57:1201–1209. doi: 10.1071/AN16680. [ DOI ] [ Google Scholar ]
• 13. Busch G., Weary D.M., Spiller A., von Keyserlingk M.A.G. American and German attitudes towards cow-calf separation on dairy farms. PLoS ONE. 2017;12:e0174013. doi: 10.1371/journal.pone.0174013. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 14. Moretti M., Vanschoenwinkel J., Van Passel S. Accounting for externalities in cross-sectional economic models of climate change impacts. Ecol. Econ. 2021;185:107058. doi: 10.1016/j.ecolecon.2021.107058. [ DOI ] [ Google Scholar ]
• 15. FOLU Growing Better: Ten Critical Transitions to Transform Food and Land Use. [(accessed on 26 January 2022)]. Available online: https://www.foodandlandusecoalition.org/wp-content/uploads/2019/09/FOLU-GrowingBetter-GlobalReport.pdf .
• 16. Nature Counting the hidden $12-trillion cost of a broken food system. Nature. 2019;574:296. doi: 10.1038/d41586-019-03117-y. [ DOI ] [ PubMed ] [ Google Scholar ]
• 17. Ly L.H., Ryan E.B., Weary D.M. Public attitudes toward dairy farm practices and technology related to milk production. PLoS ONE. 2021;16:e0250850. doi: 10.1371/journal.pone.0250850. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 18. Butler D., Holloway L. Technology and restructuring the social field of dairy farming: Hybrid capitals,‘stockmanship’and automatic milking systems. Sociol. Ruralis. 2016;56:513–530. doi: 10.1111/soru.12103. [ DOI ] [ Google Scholar ]
• 19. MacKenzie D., Wajcman J. The Social Shaping of Technology. Open University Press; New York, NY, USA: 1999. [ Google Scholar ]
• 20. Eastwood C., Klerkx L., Ayre M., Rue B. Dela Managing socio-ethical challenges in the development of smart farming: From a fragmented to a comprehensive approach for responsible research and innovation. J. Agric. Environ. Ethics. 2019;32:741–768. doi: 10.1007/s10806-017-9704-5. [ DOI ] [ Google Scholar ]
• 21. Cardoso C.S., von Keyserlingk M.G., Hötzel M.J. Views of dairy farmers, agricultural advisors, and lay citizens on the ideal dairy farm. J. Dairy Sci. 2019;102:1811–1821. doi: 10.3168/jds.2018-14688. [ DOI ] [ PubMed ] [ Google Scholar ]
• 22. Rose D.C., Wheeler R., Winter M., Lobley M., Chivers C.-A. Agriculture 4.0: Making it work for people, production, and the planet. Land Use Policy. 2021;100:104933. doi: 10.1016/j.landusepol.2020.104933. [ DOI ] [ Google Scholar ]
• 23. Rose D.C., Chilvers J. Agriculture 4.0: Broadening responsible innovation in an era of smart farming. Front. Sustain. Food Syst. 2018;2:87. doi: 10.3389/fsufs.2018.00087. [ DOI ] [ Google Scholar ]
• 24. Van der Burg S., Bogaardt M.-J., Wolfert S. Ethics of smart farming: Current questions and directions for responsible innovation towards the future. NJAS-Wageningen J. Life Sci. 2019;90:100289. doi: 10.1016/j.njas.2019.01.001. [ DOI ] [ Google Scholar ]
• 25. Bronson K. Smart farming: Including rights holders for responsible agricultural innovation. Technol. Innov. Manag. Rev. 2018;8:7–14. doi: 10.22215/timreview/1135. [ DOI ] [ Google Scholar ]
• 26. Gaworski M., de Cacheleu C., Inghels C., Leurs L., Mazarguil C., Ringot B., Tzu-Chen C. The Topic of the Ideal Dairy Farm Can Inspire How to Assess Knowledge about Dairy Production Processes: A Case Study with Students and Their Contributions. Processes. 2021;9:1357. doi: 10.3390/pr9081357. [ DOI ] [ Google Scholar ]
• 27. Stilgoe J., Owen R., Macnaghten P. Developing a framework for responsible innovation. Res. Policy. 2013;42:1568–1580. doi: 10.1016/j.respol.2013.05.008. [ DOI ] [ Google Scholar ]
• 28. Von Schomberg R. A Vision of Responsible Innovation. In: Owen R., Heintz M., Bessant J., editors. Responsible Innovation: Managing the Responsible Emergence of Science and Innovation in Society. Wiley; New York, NY, USA: 2013. pp. 51–74. [ Google Scholar ]
• 29. Macnaghten P., Shah E., Ludwig D. The Politics of Knowledge in Inclusive Development and Innovation. Routledge; London, UK: 2021. Making dialogue work: Responsible innovation and gene editing; pp. 243–255. [ DOI ] [ Google Scholar ]
• 30. Nordmann A. International Handbook on Responsible Innovation. Edward Elgar Publishing; Camberley Surrey, UK: 2019. The ties that bind: Collective experimentation and participatory design as paradigms for responsible innovation. [ DOI ] [ Google Scholar ]
• 31. OECD . Making Better Policies for Food Systems. OECD; Paris, France: 2021. [ DOI ] [ Google Scholar ]
• 32. Yunes M.C., Osório-Santos Z., von Keyserlingk M.A.G., Hötzel M.J. Gene Editing for Improved Animal Welfare and Production Traits in Cattle: Will This Technology Be Embraced or Rejected by the Public? Sustainability. 2021;13:4966. doi: 10.3390/su13094966. [ DOI ] [ Google Scholar ]
• 33. Regan Á. ‘Smart farming’in Ireland: A risk perception study with key governance actors. NJAS-Wageningen J. Life Sci. 2019;90:100292. doi: 10.1016/j.njas.2019.02.003. [ DOI ] [ Google Scholar ]
• 34. Neave H.W., Sumner C.L., Henwood R.J.T., Zobel G., Saunders K., Thoday H., Watson T., Webster J.R. Dairy farmers’ perspectives on providing cow-calf contact in the pasture-based systems of New Zealand. J. Dairy Sci. 2022;105:453–467. doi: 10.3168/jds.2021-21047. [ DOI ] [ PubMed ] [ Google Scholar ]
• 35. Krampe C., Serratosa J., Niemi J.K., Ingenbleek P. Consumer perceptions of precision livestock farming—a qualitative study in three european countries. Animals. 2021;11:1221. doi: 10.3390/ani11051221. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 36. Olynk N.J., Ortega D.L. Consumer preferences for verified dairy cattle management practices in processed dairy products. Food Control. 2013;30:298–305. doi: 10.1016/j.foodcont.2012.07.030. [ DOI ] [ Google Scholar ]
• 37. Sato P., Hötzel M.J., Von Keyserlingk M.A.G. American citizens’ views of an ideal pig farm. Animals. 2017;7:64. doi: 10.3390/ani7080064. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 38. Cardoso C.S., Von Keyserlingk M.A.G., Hötzel M.J. Brazilian citizens: Expectations regarding dairy cattle welfare and awareness of contentious practices. Animals. 2017;7:89. doi: 10.3390/ani7120089. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 39. Kenny U., Regan Á., Hearne D., O’Meara C. Empathising, defining and ideating with the farming community to develop a geotagged photo app for smart devices: A design thinking approach. Agric. Syst. 2021;194:103248. doi: 10.1016/j.agsy.2021.103248. [ DOI ] [ Google Scholar ]
• 40. Ebrahimi H.P., Schillo R.S., Bronson K. Systematic Stakeholder Inclusion in Digital Agriculture: A Framework and Application to Canada. Sustainability. 2021;13:6879. doi: 10.3390/su13126879. [ DOI ] [ Google Scholar ]
• 41. Stitzlein C., Fielke S., Fleming A., Jakku E., Mooij M. Participatory design of digital agriculture technologies: Bridging gaps between science and practice. Rural Ext. Innov. Syst. J. 2020;16:14–23. [ Google Scholar ]
• 42. Fieldsend A.F., Cronin E., Varga E., Biró S., Rogge E. ‘Sharing the space’in the agricultural knowledge and innovation system: Multi-actor innovation partnerships with farmers and foresters in Europe. J. Agric. Educ. Ext. 2021;27:1–20. doi: 10.1080/1389224X.2021.1873156. [ DOI ] [ Google Scholar ]
• 43. Sutherland L. Two good interview questions: Mobilizing the ‘good farmer’and the ‘good day’concepts to enable more-than-representational research. Sociol. Ruralis. 2021;61:681–703. doi: 10.1111/soru.12344. [ DOI ] [ Google Scholar ]
• 44. Burton R.J.F., Wilson G.A. Injecting social psychology theory into conceptualisations of agricultural agency: Towards a post-productivist farmer self-identity? J. Rural Stud. 2006;22:95–115. doi: 10.1016/j.jrurstud.2005.07.004. [ DOI ] [ Google Scholar ]
• 45. McAloon C.G., Macken-Walsh Á., Moran L., Whyte P., More S.J., O’Grady L., Doherty M.L. Johne’s disease in the eyes of Irish cattle farmers: A qualitative narrative research approach to understanding implications for disease management. Prev. Vet. Med. 2017;141:7–13. doi: 10.1016/j.prevetmed.2017.04.001. [ DOI ] [ PubMed ] [ Google Scholar ]
• 46. Fischer K., Sjöström K., Stiernström A., Emanuelson U. Dairy farmers’ perspectives on antibiotic use: A qualitative study. J. Dairy Sci. 2019;102:2724–2737. doi: 10.3168/jds.2018-15015. [ DOI ] [ PubMed ] [ Google Scholar ]
• 47. McFarland L., Macken-Walsh Á., Claydon G., Casey M., Douglass A., McGrath G., McAloon C.G. Irish dairy farmers’ engagement with animal health surveillance services: Factors influencing sample submission. J. Dairy Sci. 2020;103:10614–10627. doi: 10.3168/jds.2019-17889. [ DOI ] [ PubMed ] [ Google Scholar ]
• 48. Mulkerrins M., Beecher M., McAloon C.G., Macken-Walsh Á. Implementation of compact calving at farm-level: A qualitative analysis of farmers operating pasture-based dairy systems in Ireland. J. Dairy Sci. 2022. under review. [ DOI ] [ PubMed ]
• 49. McGuire J., Morton L.W., Cast A.D. Reconstructing the good farmer identity: Shifts in farmer identities and farm management practices to improve water quality. Agric. Human Values. 2013;30:57–69. doi: 10.1007/s10460-012-9381-y. [ DOI ] [ Google Scholar ]
• 50. McDonald R., Macken-Walsh Á., Pierce K., Horan B. Farmers in a deregulated dairy regime: Insights from Ireland’s New Entrants Scheme. Land Use Policy. 2014;41:21–30. doi: 10.1016/j.landusepol.2014.04.018. [ DOI ] [ Google Scholar ]
• 51. McDonald R., Macken-Walsh A. An actor-oriented approach to understanding dairy farming in a liberalised regime: A case study of Ireland’s New Entrants’ Scheme. Land Use Policy. 2016;58:537–544. doi: 10.1016/j.landusepol.2016.08.025. [ DOI ] [ Google Scholar ]
• 52. Deming J., Macken-Walsh Á., O’Brien B., Kinsella J. ‘Good’farm management employment: Emerging values in the contemporary Irish dairy sector. Land Use Policy. 2020;92:104466. doi: 10.1016/j.landusepol.2020.104466. [ DOI ] [ Google Scholar ]
• 53. Berry D.P. Genetics—A tool to improve productivity and profitability. Int. J. dairy Technol. 2008;61:30–35. doi: 10.1111/j.1471-0307.2008.00371.x. [ DOI ] [ Google Scholar ]
• 54. Pieper L., Doherr M.G., Heuwieser W. Consumers’ attitudes about milk quality and fertilization methods in dairy cows in Germany. J. Dairy Sci. 2016;99:3162–3170. doi: 10.3168/jds.2015-10169. [ DOI ] [ PubMed ] [ Google Scholar ]
• 55. Martin-Collado D., Diaz C., Benito-Ruiz G., Ondé D., Rubio A., Byrne T.J. Measuring farmers’ attitude towards breeding tools: The Livestock Breeding Attitude Scale. Animal. 2021;15:100062. doi: 10.1016/j.animal.2020.100062. [ DOI ] [ PubMed ] [ Google Scholar ]
• 56. Martin-Collado D., Byrne T.J., Amer P.R., Santos B.F.S., Axford M., Pryce J.E. Analyzing the heterogeneity of farmers’ preferences for improvements in dairy cow traits using farmer typologies. J. Dairy Sci. 2015;98:4148–4161. doi: 10.3168/jds.2014-9194. [ DOI ] [ PubMed ] [ Google Scholar ]
• 57. Lund T.B., Gamborg C., Secher J., Sand P. Danish dairy farmers’ acceptance of and willingness to use semen from bulls produced by means of in vitro embryo production and genomic selection. J. Dairy Sci. 2021 doi: 10.3168/jds.2020-19210. [ DOI ] [ PubMed ] [ Google Scholar ]
• 58. Denis-Robichaud J., Cerri R.L.A., Jones-Bitton A., LeBlanc S.J. Dairy producers’ attitudes toward reproductive management and performance on Canadian dairy farms. J. Dairy Sci. 2018;101:850–860. doi: 10.3168/jds.2016-12416. [ DOI ] [ PubMed ] [ Google Scholar ]
• 59. Haskell M.J. What to do with surplus dairy calves? Welfare, economic and ethical considerations. Landbauforschung. 2020;70:45–48. doi: 10.3220/LBF1593617173000. [ DOI ] [ Google Scholar ]
• 60. Balzani A., Aparacida Vaz do Amaral C., Hanlon A. A perspective on the use of sexed semen to reduce the number of surplus male dairy calves in Ireland: A pilot study. Front. Vet. Sci. 2021;7:1243. doi: 10.3389/fvets.2020.623128. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 61. Dalcq A.-C., Dogot T., Beckers Y., Brostaux Y., Froidmont E., Vanwindekens F., Soyeurt H. The Walloon farmers position differently their ideal dairy production system between a global-based intensive and a local-based extensive model of farm. PLoS ONE. 2020;15:e0223346. doi: 10.1371/journal.pone.0223346. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 62. Nicholas P.K., Mandolesi S., Naspetti S., Zanoli R. Innovations in low input and organic dairy supply chains—What is acceptable in Europe? J. Dairy Sci. 2014;97:1157–1167. doi: 10.3168/jds.2013-7314. [ DOI ] [ PubMed ] [ Google Scholar ]
• 63. Vieira A.C., Fischer V., Canozzi M.E.A., Garcia L.S., Morales-Piñeyrúa J.T. Motivations and attitudes of Brazilian dairy farmers regarding the use of automated behaviour recording and analysis systems. J. Dairy Res. 2021;88:270–273. doi: 10.1017/S0022029921000662. [ DOI ] [ PubMed ] [ Google Scholar ]
• 64. Schiano A.N., Drake M.A. Invited review: Sustainability: Different perspectives, inherent conflict. J. Dairy Sci. 2021;104:11386–11400. doi: 10.3168/jds.2021-20360. [ DOI ] [ PubMed ] [ Google Scholar ]
• 65. Proudfoot C., McFarlane G., Whitelaw B., Lillico S. Livestock breeding for the 21st century: The promise of the editing revolution. Front. Agric. Sci. Eng. 2020;7:129–135. doi: 10.15302/J-FASE-2019304. [ DOI ] [ Google Scholar ]
• 66. Lusk J.L., Roosen J., Bieberstein A. Consumer acceptance of new food technologies: Causes and roots of controversies. Annu. Rev. Resour. Econ. 2014;6:381–405. doi: 10.1146/annurev-resource-100913-012735. [ DOI ] [ Google Scholar ]
• 67. Beghin J.C., Gustafson C.R. Consumer Valuation of and Attitudes towards Novel Foods Produced with New Plant Engineering Techniques: A Review. Sustainability. 2021;13:11348. doi: 10.3390/su132011348. [ DOI ] [ Google Scholar ]
• 68. Gargiulo J.I., Eastwood C.R., Garcia S.C., Lyons N.A. Dairy farmers with larger herd sizes adopt more precision dairy technologies. J. Dairy Sci. 2018;101:5466–5473. doi: 10.3168/jds.2017-13324. [ DOI ] [ PubMed ] [ Google Scholar ]
• 69. Knaus W. Re-thinking dairy cow feeding in light of food security. AgroLife Sci. J. 2013;2:36–40. [ Google Scholar ]
• 70. Van den Pol-van Dasselaar A., Becker T., Botana Fernández A., Peratoner G. Societal and economic options to support grassland-based dairy production in Europe. Irish J. Agric. Food Res. 2021 doi: 10.15212/ijafr-2020-0128. [ DOI ] [ Google Scholar ]
• 71. Stampa E., Schipmann-Schwarze C., Hamm U. Consumer perceptions, preferences, and behavior regarding pasture-raised livestock products: A review. Food Qual. Prefer. 2020;82:103872. doi: 10.1016/j.foodqual.2020.103872. [ DOI ] [ Google Scholar ]
• 72. Schuppli C.A., Von Keyserlingk M.A.G., Weary D.M. Access to pasture for dairy cows: Responses from an online engagement. J. Anim. Sci. 2014;92:5185–5192. doi: 10.2527/jas.2014-7725. [ DOI ] [ PubMed ] [ Google Scholar ]
• 73. Kühl S., Gassler B., Spiller A. Labeling strategies to overcome the problem of niche markets for sustainable milk products: The example of pasture-raised milk. J. Dairy Sci. 2017;100:5082–5096. doi: 10.3168/jds.2016-11997. [ DOI ] [ PubMed ] [ Google Scholar ]
• 74. Boogaard B.K., Oosting S.J., Bock B.B. Defining sustainability as a socio-cultural concept: Citizen panels visiting dairy farms in the Netherlands. Livest. Sci. 2008;117:24–33. doi: 10.1016/j.livsci.2007.11.004. [ DOI ] [ Google Scholar ]
• 75. Weinrich R., Kühl S., Zühlsdorf A., Spiller A. Consumer attitudes in Germany towards different dairy housing systems and their implications for the marketing of pasture raised milk. Int. Food Agribus. Manag. Rev. 2014;17:205–222. doi: 10.22004/ag.econ.188715. [ DOI ] [ Google Scholar ]
• 76. Musto M., Cardinale D., Lucia P., Faraone D. Influence of different information presentation formats on consumer acceptability: The case of goat milk presented as obtained from different rearing systems. J. Sens. Stud. 2015;30:85–97. doi: 10.1111/joss.12140. [ DOI ] [ Google Scholar ]
• 77. Hötzel M.J., Cardoso C.S., Roslindo A., von Keyserlingk M.A.G. Citizens’ views on the practices of zero-grazing and cow-calf separation in the dairy industry: Does providing information increase acceptability? J. Dairy Sci. 2017;100:4150–4160. doi: 10.3168/jds.2016-11933. [ DOI ] [ PubMed ] [ Google Scholar ]
• 78. Joubran A.M., Pierce K.M., Garvey N., Shalloo L., O’Callaghan T.F. Invited review: A 2020 perspective on pasture-based dairy systems and products. J. Dairy Sci. 2021 doi: 10.3168/jds.2020-19776. [ DOI ] [ PubMed ] [ Google Scholar ]
• 79. Smid A.-M.C., Weary D.M., von Keyserlingk M.A.G. The influence of different types of outdoor access on dairy cattle behavior. Front. Vet. Sci. 2020;7:257. doi: 10.3389/fvets.2020.00257. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 80. Cuttle S.P. Impacts of pastoral grazing on soil quality. In: McDowell R.W., editor. Environmental Impacts of Pasture-Based Farming. CAB International; Wallingford, UK: 2008. pp. 33–74. [ Google Scholar ]
• 81. Smid A.-M.C., Inberg P.H.J., de Jong S., Sinclair S., von Keyserlingk M.A.G., Weary D.M., Barkema H.W. Perspectives of Western Canadian dairy farmers on providing outdoor access for dairy cows. J. Dairy Sci. 2021;104:10158–10170. doi: 10.3168/jds.2021-20342. [ DOI ] [ PubMed ] [ Google Scholar ]
• 82. Hartwiger J., Schären M., Potthoff S., Hüther L., Kersten S., Von Soosten D., Beineke A., Meyer U., Breves G., Dänicke S. Effects of a change from an indoor-based total mixed ration to a rotational pasture system combined with a moderate concentrate feed supply on rumen fermentation of dairy cows. Animals. 2018;8:205. doi: 10.3390/ani8110205. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 83. Tamminga S., Bannink A., Dijkstra J., Zom R.L.G. Feeding Strategies to Reduce Methane Loss in Cattle. Animal Sciences Group; Lelystad, The Netherlands: 2007. [ Google Scholar ]
• 84. Martin C., Morgavi D.P., Doreau M. Methane mitigation in ruminants: From microbe to the farm scale. Animal. 2010;4:351–365. doi: 10.1017/S1751731109990620. [ DOI ] [ PubMed ] [ Google Scholar ]
• 85. Naspetti S., Mandolesi S., Buysse J., Latvala T., Nicholas P., Padel S., Van Loo E.J., Zanoli R. Determinants of the acceptance of sustainable production strategies among dairy farmers: Development and testing of a modified technology acceptance model. Sustainability. 2017;9:1805. doi: 10.3390/su9101805. [ DOI ] [ Google Scholar ]
• 86. Palczynski L.J., Bleach E.C.L., Brennan M.L., Robinson P.A. Stakeholder perceptions of disease management for dairy calves:“it’s just little things that make such a big difference”. Animals. 2021;11:2829. doi: 10.3390/ani11102829. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 87. Perttu R.K., Ventura B.A., Endres M.I. Youth and adult public views of dairy calf housing options. J. Dairy Sci. 2020;103:8507–8517. doi: 10.3168/jds.2019-17727. [ DOI ] [ PubMed ] [ Google Scholar ]
• 88. Vellinga T.V., De Haan M.H.A., Schils R.L.M., Evers A., van den Pol–van Dasselaar A. Implementation of GHG mitigation on intensive dairy farms: Farmers’ preferences and variation in cost effectiveness. Livest. Sci. 2011;137:185–195. doi: 10.1016/j.livsci.2010.11.005. [ DOI ] [ Google Scholar ]
• 89. Lavoie A., Wardropper C.B. Engagement with conservation tillage shaped by “good farmer” identity. Agric. Human Values. 2021;38:1–11. doi: 10.1007/s10460-021-10205-1. [ DOI ] [ Google Scholar ]
• 90. Burton J.F., Forney J., Stock P., Sunderland L. The ‘Good Farmer’in Communities of Practice. Routledge; New York, NY, USA: 2020. [ Google Scholar ]
• 91. Sinnott A.M., Kennedy E., Bokkers E.A.M. The effects of manual and automated milk feeding methods on group-housed calf health, behaviour, growth and labour. Livest. Sci. 2021;244:104343. doi: 10.1016/j.livsci.2020.104343. [ DOI ] [ Google Scholar ]
• 92. Medrano-Galarza C., LeBlanc S.J., Jones-Bitton A., DeVries T.J., Rushen J., de Passillé A.M., Haley D.B. Producer perceptions of manual and automated milk feeding systems for dairy calves in Canada. Can. J. Anim. Sci. 2017;98:250–259. doi: 10.1139/cjas-2017-0038. [ DOI ] [ Google Scholar ]
• 93. Wilson D.J., Pempek J.A., Roche S.M., Creutzinger K.C., Locke S.R., Habing G., Proudfoot K.L., George K.A., Renaud D.L. A focus group study of Ontario dairy producer perspectives on neonatal care of male and female calves. J. Dairy Sci. 2021;104:6080–6095. doi: 10.3168/jds.2020-19507. [ DOI ] [ PubMed ] [ Google Scholar ]
• 94. Sumner C.L., von Keyserlingk M.A.G., Weary D.M. Perspectives of farmers and veterinarians concerning dairy cattle welfare. Anim. Front. 2018;8:8–13. doi: 10.1093/af/vfx006. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 95. Clark B., Stewart G.B., Panzone L.A., Kyriazakis I., Frewer L.J. A systematic review of public attitudes, perceptions and behaviours towards production diseases associated with farm animal welfare. J. Agric. Environ. Ethics. 2016;29:455–478. doi: 10.1007/s10806-016-9615-x. [ DOI ] [ Google Scholar ]
• 96. Beaver A., Proudfoot K.L., von Keyserlingk M.A.G. Symposium review: Considerations for the future of dairy cattle housing: An animal welfare perspective. J. Dairy Sci. 2020;103:5746–5758. doi: 10.3168/jds.2019-17804. [ DOI ] [ PubMed ] [ Google Scholar ]
• 97. Roche J.R., Berry D.P., Bryant A.M., Burke C.R., Butler S.T., Dillon P.G., Donaghy D.J., Horan B., Macdonald K.A., Macmillan K.L. A 100-year review: A century of change in temperate grazing dairy systems. J. Dairy Sci. 2017;100:10189–10233. doi: 10.3168/jds.2017-13182. [ DOI ] [ PubMed ] [ Google Scholar ]
• 98. Holloway L., Bear C. Bovine and human becomings in histories of dairy technologies: Robotic milking systems and remaking animal and human subjectivity. BJHS Themes. 2017;2:215–234. doi: 10.1017/bjt.2017.2. [ DOI ] [ Google Scholar ]
• 99. Driessen C., Heutinck L.F.M. Cows desiring to be milked? Milking robots and the co-evolution of ethics and technology on Dutch dairy farms. Agric. Human Values. 2015;32:3–20. doi: 10.1007/s10460-014-9515-5. [ DOI ] [ Google Scholar ]
• 100. Hansen B.G. Robotic milking-farmer experiences and adoption rate in Jæren, Norway. J. Rural Stud. 2015;41:109–117. doi: 10.1016/j.jrurstud.2015.08.004. [ DOI ] [ Google Scholar ]
• 101. De Koning K. Proceedings of the Dairy Research Foundation Symposium. The University of Sydney; Camden, Australia: 2011. Automatic milking: Common practice on over 10,000 dairy farms worldwide; pp. 14–31. [ Google Scholar ]
• 102. Medeiros I., Fernandez-Novo A., Astiz S., Simões J. Production and Health Management from Grazing to Confinement Systems of Largest Dairy Bovine Farms in Azores: A Farmers’ Perspective. Animals. 2021;11:3394. doi: 10.3390/ani11123394. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 103. Hyde J., Engel P. Investing in a robotic milking system: A Monte Carlo simulation analysis. J. Dairy Sci. 2002;85:2207–2214. doi: 10.3168/jds.S0022-0302(02)74300-2. [ DOI ] [ PubMed ] [ Google Scholar ]
• 104. Rotz C.A., Coiner C.U., Soder K.J. Automatic milking systems, farm size, and milk production. J. Dairy Sci. 2003;86:4167–4177. doi: 10.3168/jds.S0022-0302(03)74032-6. [ DOI ] [ PubMed ] [ Google Scholar ]
• 105. Reinemann D.J. Robotic milking: Current situation; Proceedings of the 47th Anniversary Meeting National Mastitis Council; New Orleans, LA, USA. 20–23 January; 2008. [(accessed on 26 January 2022)]. pp. 75–80. Available online: https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.599.9311&rep=rep1&type=pdf . [ Google Scholar ]
• 106. Schewe R.L., Stuart D. Diversity in agricultural technology adoption: How are automatic milking systems used and to what end? Agric. Human Values. 2015;32:199–213. doi: 10.1007/s10460-014-9542-2. [ DOI ] [ Google Scholar ]
• 107. Butler D., Holloway L., Bear C. The impact of technological change in dairy farming: Robotic milking systems and the changing role of the stockperson. J. R. Agric. Soc. Engl. 2012;173:1–6. [ Google Scholar ]
• 108. Prescott N.B., Mottram T.T., Webster A.J.F. Relative motivations of dairy cows to be milked or fed in a Y-maze and an automatic milking system. Appl. Anim. Behav. Sci. 1998;57:23–33. doi: 10.1016/S0168-1591(97)00112-3. [ DOI ] [ Google Scholar ]
• 109. Svennersten-Sjaunja K.M., Pettersson G. Pros and cons of automatic milking in Europe. J. Anim. Sci. 2008;86:37–46. doi: 10.2527/jas.2007-0527. [ DOI ] [ PubMed ] [ Google Scholar ]
• 110. Holloway L., Bear C., Wilkinson K. Robotic milking technologies and renegotiating situated ethical relationships on UK dairy farms. Agric. Human Values. 2014;31:185–199. doi: 10.1007/s10460-013-9473-3. [ DOI ] [ Google Scholar ]
• 111. Hovinen M., Pyörälä S. Invited review: Udder health of dairy cows in automatic milking. J. Dairy Sci. 2011;94:547–562. doi: 10.3168/jds.2010-3556. [ DOI ] [ PubMed ] [ Google Scholar ]
• 112. Lyons N.A., Kerrisk K.L., Garcia S.C. Milking frequency management in pasture-based automatic milking systems: A review. Livest. Sci. 2014;159:102–116. doi: 10.1016/j.livsci.2013.11.011. [ DOI ] [ Google Scholar ]
• 113. Millar K.M., Tomkins S.M., White R.P., Mepham T.B. Consumer attitudes to the use of two dairy technologies. Br. Food J. 2002 doi: 10.1108/00070700210418721. [ DOI ] [ Google Scholar ]
• 114. Pfeiffer J., Gabriel A., Gandorfer M. Understanding the public attitudinal acceptance of digital farming technologies: A nationwide survey in Germany. Agric. Human Values. 2021;38:107–128. doi: 10.1007/s10460-020-10145-2. [ DOI ] [ Google Scholar ]
• 115. Silvi R., Pereira L.G.R., Paiva C.A.V., Tomich T.R., Teixeira V.A., Sacramento J.P., Ferreira R.E.P., Coelho S.G., Machado F.S., Campos M.M. Adoption of Precision Technologies by Brazilian Dairy Farms: The Farmer’s Perception. Animals. 2021;11:3488. doi: 10.3390/ani11123488. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 116. Heutinck L.F.M., Driessen C. The ethics of automatic milking systems and grazing in dairy cattle. In: Zollitsch W., Winckler C., Waiblinger S., Haslberger A., editors. Sustainable Food Production and Ethics. Wageningen Academic Publishers; Wageningen, The Nethelands: 2007. pp. 249–254. [ Google Scholar ]
• 117. Greehy G.M., McCarthy M.B., Henchion M.M., Dillon E.J., McCarthy S.N. Complexity and conundrums. Citizens’ evaluations of potentially contentious novel food technologies using a deliberative discourse approach. Appetite. 2013;70:37–46. doi: 10.1016/j.appet.2013.06.083. [ DOI ] [ PubMed ] [ Google Scholar ]
• 118. Toumey C. Science in the service of citizens and consumers. Nat. Nanotechnol. 2011;6:3–4. doi: 10.1038/nnano.2010.263. [ DOI ] [ PubMed ] [ Google Scholar ]
• 119. Cook B.R., Zurita M.d.L.M. Fulfilling the promise of participation by not resuscitating the deficit model. Glob. Environ. Chang. 2019;56:56–65. doi: 10.1016/j.gloenvcha.2019.03.001. [ DOI ] [ Google Scholar ]
• 120. Spooner J.M., Schuppli C.A., Fraser D. Attitudes of Canadian citizens toward farm animal welfare: A qualitative study. Livest. Sci. 2014;163:150–158. doi: 10.1016/j.livsci.2014.02.011. [ DOI ] [ Google Scholar ]
• 121. Henchion M. What does a cow do? And why, and to whom, is this important?; Proceedings of the European Parliament Committee on Agriculture and Rural Development Hearing on ‘Perspectives of Animal Production in the EU in the Context of the Green Deal, Farm to Fork Biodiversity Strategies 2021; Brussles, Belgium. 22 June 2021. [ Google Scholar ]
• 122. Zuliani A., Esbjerg L., Grunert K.G., Bovolenta S. Animal welfare and mountain products from traditional dairy farms: How do consumers perceive complexity? Animals. 2018;8:207. doi: 10.3390/ani8110207. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 123. Ventura B.A., Von Keyserlingk M.A.G., Wittman H., Weary D.M. What difference does a visit make? Changes in animal welfare perceptions after interested citizens tour a dairy farm. PLoS ONE. 2016;11:e0154733. doi: 10.1371/journal.pone.0154733. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 124. Von Keyserlingk M.A.G., Martin N.P., Kebreab E., Knowlton K.F., Grant R.J., Stephenson M., Sniffen C.J., Harner Iii J.P., Wright A.D., Smith S.I. Invited review: Sustainability of the US dairy industry. J. Dairy Sci. 2013;96:5405–5425. doi: 10.3168/jds.2012-6354. [ DOI ] [ PubMed ] [ Google Scholar ]
• 125. IJzerman H., Lewis N.A., Przybylski A.K., Weinstein N., DeBruine L., Ritchie S.J., Vazire S., Forscher P.S., Morey R.D., Ivory J.D., et al. Use caution when applying behavioural science to policy. Nat. Hum. Behav. 2020;4:1092–1094. doi: 10.1038/s41562-020-00990-w. [ DOI ] [ PubMed ] [ Google Scholar ]
• 126. Eldredge L.K.B., Markham C.M., Ruiter R.A.C., Fernández M.E., Kok G., Parcel G.S. Planning Health Promotion Programs: An Intervention Mapping Approach. John Wiley & Sons; New York, NY, USA: 2016. [ Google Scholar ]
• 127. Macken-Walsh Á., Henchion M., Regan Á. Come on Board’ The Systems-Based Approach: The Role of Social Science in Agri-Food Research & Innovation. Irish J. Agric. Food Res. 2021 [ Google Scholar ]
• 128. Graddy-Lovelace G. Farmer and non-farmer responsibility to each other: Negotiating the social contracts and public good of agriculture. J. Rural Stud. 2021;82:531–541. doi: 10.1016/j.jrurstud.2020.08.044. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]

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A review of megatrends in the global dairy sector: what are the socioecological implications?

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• Published: 14 July 2022
• Volume 40 , pages 373–394, ( 2023 )

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• Milena Bojovic   ORCID: orcid.org/0000-0002-9470-9058 1 &
• Andrew McGregor 1  

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The global dairy industry is undergoing a period of expansion and consolidation, alongside heightened critique and competition from non-dairy alternatives. This review identifies four key megatrends within the global dairy sector, focusing in on the socioecological challenges associated with each. The megatrends were identified through a literature review of recent publications within the dairy science and social science fields, as well as a review of grey literature from intergovernmental and institutional reports. Key findings include geographical range shifts in production and consumption of dairy milk from the Global North to the Global South; intensification of production agendas that strive for mechanisation, standardisation, and corporatisation of the sector; increasing awareness of the ecological impacts of intensive dairying; and finally, disruptions to the sector driven by plant-based milks and, potentially, synthetic milks. We identify under-researched socioecological challenges associated with each of these trends. Although dairy milk may be homogenous in its final form, the sector remains heterogenous in its impacts across spaces, places, and scales, as increasingly intensive dairying systems fundamentally reshape human–cattle relations. The combined impacts of these trends bring into question the mythologies of milk and the assumed desirability of ever-expanding dairy industries. Our review finds that the future of dairy is not clear nor uncontroversial and that more attention needs to be directed to maximising and broadening the social benefits of the dairy and dairy alternatives, minimising the human and non-human costs, and limiting contributions to global climate change.

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Introduction

Dairy Footnote 1 milk exists as a fresh product (as milk or by-products of milk), in powdered forms, and as a synthesized set of proteins and fats in industrial foodstuffs. The United Nations Food and Agriculture Organisation (FAO 2019 ) estimates that over 80% of the world’s population consume dairy products on a regular basis. Innumerable human and non-human lives and associated ecologies are entangled in milk production and consumption, creating social and ecological (socioecological) vulnerabilities that are casting clouds over the future of the sector. Based on the analysis below, we believe the global dairy sector is likely to undergo a period of significant transition over the next few decades.

There have been increasing calls to move beyond animal-based food systems to more sustainable forms of food production in a bid to address the true costs of animal agriculture and build more resilient food systems (for example, see Poore and Nemecek 2018 ; Springmann et al. 2018 ; Willet et al. 2018; Pieper et al. 2020 ). Morris et al. ( 2021 , p. 2) characterise this shift as a “societal grand challenge”. In this paper we engage with this challenge by synthesising current trends in dairy and identifying emerging challenges and opportunities. The aim is to generate knowledge that can contribute to research agendas and policy dialogues about how to live (and eat) sustainably in the current epoch of global environmental change.

Our approach differs from other reviews of the sector conducted via institutional sustainability reports, dairy sciences, or agricultural economics that tend to focus upon expansion and growth within the sector. Instead, we analyse the socioecological dimensions of change. In doing so we are interested in how people, places and environments are being affected by trends within the dairy sector in order to highlight unintentional or hidden impacts of change.

The first section of the paper explains the methodological framing for this review. Following this, we identify four megatrends, where megatrends are approached as trajectories of social, economic, environmental, or technological change occurring over the coming decades that “continually reshape the world around us” (Hajkowicz 2015 , p. 3). The four trends we identify are:

Shifting geographies and scales of  production and consumption,

Intensification of capital, land and animals, 

Growing awareness of the ecological impacts of dairy,

Alternative milk distruptions.

The discussion section of the paper synthesises the four trends to reveal how they come together to inform the scale and diversity of challenges facing the sector and their associated socioecological implications. Our analysis raises questions about the mythologies of milk, particularly the often-unspoken assumption that an ever-expanding industry is good for people, cattle or the planet.

Methodology

In this section, we explain our methodological approach. We outline our data collection process, how we are approaching socioecological impacts, and how we define and identify megatrends. We also briefly reflect on the limitations of our review through what was included and excluded through this process. Before continuing, it is important to note our focus is on planetary trends, however we are also interested in differences between the countries commonly grouped as the Global North and Global South. Countries in the Global North include European, North American, Australian and New Zealand dairy industries, whereas the Global South incorporates predominantly Asian, African and Latin American markets. We draw on these imagined geographies to discuss trends, though we acknowledge that the reality of these categories is much more nuanced and a detailed synthesis of each region’s dairy industry is likely to reveal much greater diversity and difference.

Data selection process

To begin the process for this review, we read through recent grey literature produced by influential multilateral institutions that reported on the current state and future modelling of the global dairy sector. This included reports from the United Nations FAO (see FAO 2019 , 2020 ; FAO et al. 2020 ), the OECD–FAO coalition (see OECD–FAO 2010 , 2020 , 2021 ), as well as information from the Intergovernmental Panel on Climate Change (IPCC) special report on land and climate change (see Mbow et al. 2019 ). We also analysed high profile papers that have examined the role of livestock within future food systems in the context of climate change (see Springmann et al. 2019; Willet et al. 2018). After reading these reports, key search terms were chosen based upon reoccurring themes in the literature. These were used in Scopus and Google Scholar database searches and included terms like “dairy trends”, “dairy review”, “dairy” AND “sustainability”, “climate change”, “plant-based milks”, “synthetic dairy”, “synthetic milks” and similar searches.

In this scoping study, we prioritised articles from the period 2017 to 2021. Footnote 2 We followed a similar review process to Aschemann-Witzel et al. ( 2020 ) work on plant-based trends to inform our selection of academic literature, focussing on peer-reviewed journal articles published in the past 5 years that highlighted the most current trends and issues in the sector. Our search highlighted academic literature that came predominantly from the fields of dairy science, food innovation and social science scholarship. We initially identified academic reviews of the dairy sector, such as those published within the Journal of Dairy Science (see Beaver et al. 2020 ; Schuster et al. 2020 ; Britt et al. 2018 ; Pulina et al. 2018 ; McCarthy et al. 2017 ) and other key review papers across different environmental, social and nutritional journals about dairy production and consumption (see Gauly et al. 2013 ; Aschemann-Witzel et al. 2020 ; Fiel et al. 2020 ; Roy et al. 2020 ; Stephens 2020 ; Hjalsted et al. 2020 ; Lonkila and Kaljonen 2021 ; Cogato et al. 2021 ; Wankar et al. 2021 ). We narrowed in on the reviews that we felt had particular relevance to our socioecological framing. We also purposively selected 40 case study papers referred to in the reviews that concentrated upon a socioecological dimension of a megatrend we were interested in, such as plant-based milks or intensification. Our data selection process is shown in Fig.  1 . A list of all reviewed articles is available in “Appendix”.

Flow chart of data selection process for our review

Socioecological analysis

Our review centres upon the megatrends that are contributing to socioecological change within dairy industries. Rather than see ecological or social impacts bracketed off from one another as may be the case in an economic or environment review, we attempt to bring the multiple human and non-human actors that comprise dairying, including the economies, environments and bodies that enable and are shaped by dairying, into view and consideration. Our approach has been influenced by political ecology, more-than-human geography and the broader environmental humanities, which highlight that the relations between things as an important factor in shaping the world (see Whatmore 2002 ; Latour 1999 ; Haraway 2003 ). Concepts like “co-becoming” recognise how humans, cattle and environments never evolve on their own but are caught up in complex relations that change over time. Here we are interested in identifying the megatrends that are reshaping these relations within dairy industries and the ramifications for the human and non-human actors within it. This requires recognising cattle as “lively” more-than-human actors (Collard and Dempsey 2013 ; Holloway and Bear 2017 ; Bear and Holloway 2019 ; Gillespie and Collard 2015; Gillespie 2021 ) who shape and are shaped by these trends and highlighting the intended and unintended outcomes of dairy industries at different scales (for example, see McGregor et al. 2021 ). It also requires a level of abstraction, as we cannot do justice to the in-depth ethnographic work on dairying, and instead draw upon selected case study research to help think through some of the impacts of megatrends for socioecological communities.

In doing so, we build upon and extend the work of Clay and Yurco ( 2020 ) on the political ecology of milk, Clay et al.’s ( 2020b ) examination of the drivers of dairy intensification and possibilities of dairy alternatives, Mylan et al.’s ( 2019 ) exploration of the possibilities of plant-based milk and Zafrilla et al.’s ( 2020 ) review of the sustainability challenges to dairy livestock systems. These researchers have begun challenging the implicit assumption in much of the literature that dairy should be encouraged to grow and expand. Instead, our socioecological analysis problematises this thinking by tracing how megatrends in dairy are related to changing relations and socioecological wellbeing of humans, non-humans, and environments. In doing so we follow Sexton et al. ( 2019 , p. 48) who argue that such approaches can create more openings for narratives that evoke and invent “more compassionate human–animal relationships”.

Data analysis: identifying megatrends

The idea of megatrends was first introduced by Naisbitt (1982) as a means identifying new ideas, interpretative communities, ways of knowing and worldviews for subsequent analysis (Slaughter 1993 ). The mega refers to the macro-scale of the processes and the likely impacts of the trend, with Mittelstaedt et al. ( 2014 , p. 254) arguing that megatrends are complex “social science constructs” which are “seismic in their effect, both in time and space”. They are “seismic” because as Visconti et al. ( 2014 , p. 363) assert, a megatrend “is the beginning of a new trajectory that interrogates the established direction a system has followed before”. As such megatrends destabilise the status quo creating new opportunities and challenges for those reliant upon existing structures. They are social because, as Rohner ( 2018 , p. 30) contends, megatrends “impacts the lens with which society views the world, thus influencing values and thinking”. We approach megatrends within dairy as sector-wide processes that are transforming how and where the dairy sector operates and how socioecologies are affected by and interact with dairying. Megatrends shape and are shaped by existing socioecological structures including institutional systems, organisations, operations, environments and human and non-human actors (Turner 2005 ).

We identified megatrends in the global dairy sector through an iterative process. We first identified a broad range of reoccurring themes that appeared in the grey and academic literature that related to socioecological challenges and opportunities. Each of these themes are relevant to the dairy sector, are discussed in dairy industry reviews, and tend to attract case study research. We then sought to group these themes to identify the broader megatrend of which they were a part. For example, robotics and automated milking is an important theme that is transforming elements of the sector however the disruptive influence of automation is much more significant when considered alongside the related themes of corporatisation and standardisation, both of which are aligned with automation, collectively contributing to a megatrend around dairy intensification. Similarly, while dairy emissions are a source of much analysis, when combined with various other issues in the literature, such as the climate change induced heat stress or resource depletion, they combine to form a sector wide megatrend about the growing concern of various aspects of dairying’s relationship with the environment. Themes shifted to megatrends when they could be grouped in a way that suggested macro-scale, sector-wide changes. The themes and megatrends are evident in Fig.  2 .

Mind map used to identify themes and megatrends process

In focusing on socioecological dimensions of megatrends and identifying them in this iterative way we do not attempt to identify all the trends happening across the dairy sector. There are two main gaps in our analysis. First, we do not focus in on trends within dairying subfields such as food science, genetics, nutrition, or veterinary science. While important advancements are occurring in each of these fields it is only at the point in which trends in these fields impact the broader socioecological relations of the dairy industry that they would become incorporated into this analysis. Second, and relatedly, our focus is upon large scale trends that are occurring now in the dairy sector rather than a focus on emerging research priorities or small-scale changes. As such we acknowledge, for example, that there is a great deal of promising discussion about climate smart and regenerative agriculture amongst key multilateral bodies (for example, see FAO 2021), however, based on our review of the literature, this has yet to have widespread impacts that are causing a seismic shift within the sector. Instead, we see these sorts of initiatives as themes that emerging as part of a broader megatrend concerned about the environmental impacts of dairying. Indeed, if such initiatives are to gain widespread uptake, they will need to engage with other more established megatrends, such as intensification, that seems to push in counter directions. We now discuss each megatrend in turn.

Shifting geographies and scales of production and consumption: from North to South

Consumption of dairy milk Footnote 3 was historically contingent on regional availabilities of resources, arable land, population growth and access to cattle. Cattle originated in the Middle East but became domesticated in many parts of the world and embedded in local dairy systems. Cattle ranges expanded considerably through colonialism when these “creatures of empire” played a key role in territorial expansion (Anderson 2004 ). By the twentieth century, narratives about milk had become mythologised, associated with generalised goodness and story lines of “modernisation, progress and nation building” within European and North American markets (Clay and Yurco 2020 , p. 3). High intake of dairy products has been widely promoted in Northern countries, often for bone health due to its high calcium content (Willet et al. 2019). The dairy industry is now well established in the Global North with consumption of fresh dairy projected to reach 25.2 kg per capita of milk solids by 2030, compared with 12.6 kg per capita Footnote 4 (OECD–FAO 2021 , p. 179) in the South. However, as we discuss below, demand for dairy milk has flattened out or is declining in some countries in the North where plant-based milks are capturing part of the market.

Dairy milk has since proven globally attractive with demands for animal-based proteins (meat and dairy) increasing in poorer countries as incomes rise (Stephens 2020 ). Increasing dairy consumption is part of the so-called “nutrition transition” (Popkin 2003 ) that necessitates an accompanying “livestock revolution” (Delgado 2003 ) to produce more meat and dairy. Advertising campaigns supporting the consumption of milk (see Zafrilla et al. 2018) are increasing demands for fresh dairy products in growing markets across the Global South, particularly in India, Pakistan and parts of Africa (OECD–FAO 2020 , p. 175). For example, OECD–FAO ( 2020 ) find that more “away-from-home” eating in Southeast Asian countries is driving up demand for dairy consumption, such as cheese, as consumers eat more processed fast-foods.

Part of the success of dairy expansion has come from the adaptability of milk products, which can be transported in powdered forms. At present, fresh dairy products tend to be more expensive in the Global South (such as Sub-Saharan Africa, Eastern and South-eastern Asia) than in the Global North as fresh milk is more expensive to trade due to its highly perishable nature (FAO et al. 2020 ). To ensure a constant and cheaper supply of longer-life milk, fresh milk is converted to powdered forms, for which an integrated network of export markets have been developed. Most dairy imports and exports are in the form of whole milk powder (WMP) or skim milk powder (SMP) (OECD–FAO 2020 ). The major dairy exporters are New Zealand, the European Union and the United States (OECD–FAO 2020 ).

The OECD–FAO Agricultural Outlook (2021) projections for 2021–2030 have modelled increased production across developed and developing countries, according to kilo tonnes per week (kt pw) shown in Table 1 . This is in line with OECD–FAO ( 2010 ) findings from a decade earlier, which projected more milk will be produced outside of the OECD and that growth is expected for all dairy products with WMP, butter and cheese having the strongest growth. Production in the Global South now outstrips that of the North, much of it associated with rapid growth in India and China. However given approximately 80% of the world’s population is in the South, it is still lower on a per capita basis. Nevertheless, the present outlook clearly identifies a period of rapid growth for the dairy sector in the Global South as it is predicted to expand by approximately a third in the next 10 years as shown in Table 1 .

According to Rabobank’s annual listing of top global dairy companies by turnover for 2020 (see Table 2 ), most large dairy organisations are from the Global North (Ledman and van Buttum 2020). Each of these multibillion-dollar companies owns multiple brands of both dairy products (milks, yoghurts, cheeses) as well as by-products that contain milk (confectionary, pet food, cereals) (Nestle 2021 ). However, dairy companies from China have moved up in ranking in recent years due to expanding total net worth and production capacity (through more mechanised forms of milk production). The Yili Group, which is known as Asia’s largest dairy firm (Dairy Industries International 2020), has expanded its global reach, with partnerships involving Thailand, New Zealand, Italy, the Netherlands and Uruguay (Oceania Dairy 2020 ).

The recent and accelerating growth in dairy production in the South is occurring when the sector looks very different to what it did when it originally expanded in the North. As will be discussed, dairy is more corporatised, mechanised and mobile, and must compete in national and international markets, not just local ones. Current conditions favour capital-intensive rather than labour-intensive operations, favouring larger businesses over more traditional smaller family run farms. Dairy has become a key site of investment and capital accumulation, influencing the form and shape of the industry as it expands in the Global South. This presents land use and livelihoods challenges for small scale farms and farming communities and raises questions about who benefits from the expansion of dairy in the Global South across spaces and scales. The rapid growth of dairy production and consumption in the Global South means that the socioecological challenges of dairy expansion will be concentrated there, as we discuss below.

Intensification of capital, land, and animals

Multiple and inter-related processes of dairy intensification represent a second megatrend in the dairy sector. The growth of large dairy companies (see Table 2 ) has resulted in an intensification of capital amongst a smaller group of influential actors, who have, in turn, sought to maximise profits by intensifying production, making the most out of dairying land and dairying bodies, both human and non-human. While milk production has historically been undertaken by pasture-based smallholder farms, economies of scale favour larger corporate entities over these smaller traditional businesses. This can result in smaller farms being bought out or replaced through a variety of means and consolidated into large dairy production systems who can invest in mechanisation and meet industry standards for greater profitability. Improved national and international transportation and processing systems enables this transition as more distant players can compete in what used to be mainly local markets. Further consolidation of dairy farms through processes of mergers, acquisitions and strategic alliances in the dairy industry are expected to continue (Knips 2005 ) as less competitive smaller dairy farms exit the market (for example, see Sewell 2021 ).

One of the drivers of capital intensification are the sanitation and quality standards demanded in contemporary food systems. Quality assurance for food is now an essential element within the global food industry and it is widely acknowledged that as standards become stricter, food manufacturers are required to invest in infrastructure and quality controls to remain competitive (Kotsanopoulos and Arvanitoyannis 2017 ). Agri-food chains are governed by strong interdependencies among retailers and controlling bodies that impose a variety of regulations (Gianni et al. 2017 ). The dairy sector is no exception to this, with increased public awareness regarding food safety pushing the dairy sector to improve the safety and image of dairy products (Ding et al. 2019 ). Britt et al. ( 2018 ) argue that structural consolidation of dairy farming will continue as the sector becomes more vertically integrated and that this requires more inputs to ensure milk products are meeting product quality demands, resulting in more resource and energy intensive production lines. From the collection of milk to the process of pasteurisation, homogenisation, storage, packaging, and distribution, each of these components comes with its own social, political, economic and environmental costs and expectations. Dairy processing, for example, is recognised as one of the most energy intensive sectors within the food industry (Briam et al. 2015 ; Challis et al. 2017 ; Ladha-Sabur et al. 2019 ), having particular safety requirements due to the perishable nature and limited shelf life of milk (Douphrate et al. 2013 ).

Meeting these standards can be difficult for small dairy producers and “traditional” household producers due to a lack of access to modern processing technologies and the time and expense meeting such standards may incur (Britt et al. 2018 ). Cattle bodies and outputs like milk vary dramatically across space and environments. While the push for quality standards advantages larger players as a form of risk management, it is having significant impacts upon those who cannot meet those standards (Lonkila and Kaljonen 2021 ). In a case study on family farms in the Global South, Bosc et al. ( 2018 , p. 313) found that the functioning of family farms is often far removed from the “standards of agricultural specialisation” required by public policies. Regional differences in terms of development, regulations and exporting opportunities (Kotsanopoulos and Arvanitoyannis 2017 ) risks further marginalising smaller and poorer farmers who may not be able to meet and adapt to changing expectations. For example, Minten et al. ( 2020 ) found that although dairy milk production, quality and supply is increasing due to the prevalence of larger scale farms and their capacity to adopt new technologies and resources, smaller farms are increasingly excluded “because of relatively higher coordination costs that downstream firms in the value chain incur in their commercial engagements with these small farms” (Minten et al. 2020 , p. 2). Reardon et al. ( 2009 ), similarly found that there was a trend of shifting from local sourcing in countries in the Global South to national, regional, and global networks to reduce cost and increase efficiencies within a competitive market context. China estimates that at least 100,000 small-scale dairy farmers have stopped farming altogether since 2010, not helped by a ban on the collection of milk from many small-scale family farms due to concerns about milk quality (Bai et al. 2018 ).

A second driver and outcome of a more consolidated and intensive dairy sector has been investment in new technologies such as robotics to reduce labour costs. Automatic milking systems (AMS) represent the most advanced shift towards mechanisation in the sector. Introduced in the 1990s (Jacobs and Siegford 2012 ), AMS essentially involves robots automatically milking cows, minimising the need for conventional human intervention/labour. The world’s largest “milking carousel” was recently acquired by one of China’s leading producers of raw milk, Lvyuan Animal Husbandry (GEA Group 2020 ). This machine is capable of milking 10,000 cows, 3 times per day. While technical apparatuses such as milking machines facilitate a more efficient production process, thereby reducing costs and providing a competitive advantage over smaller non-automated producers, it also generates a disembodied and increased moral distance between humans and the cattle as both become progressively alienated from one another (Clarke and Knights 2021 ; Holloway and Bear 2017 ). AMS encourages a shift away from animal husbandry and multispecies relations to a much more mechanical relationship where the metrics for animal health and wellbeing are quantified in artificial intelligence systems.

Mechanisation in milking, along with the increased prominence of feedlot rather than pasture-based production systems, are intensifying dairy production in increasingly corporatized environments (Clay et al. 2020b ). Increased intensification of dairy agriculture reinforces objectifying constructions of cows as commodities whose primary value comes from their ability to produce milk that can be sold for profit. Alternative ways of engaging with them as feeling complex beings (Schuster et al. 2020 ) becomes more and more difficult as human–cow encounters become rarer, routinised and limited. Farmers are now producing more for less, however there are also less farmers and farm workers needed to produce this milk, and cows have less opportunity to build more felt and caring relationships with humans. These intensive systems of production face the accusations of animal cruelty, a lack of transparency, and “placelessness”, that have long been levelled at intensive animal agricultural systems (Sexton et al. 2019 , p. 64; Gillespie 2018 ). The effort to make milk quicker, cheaper and more homogenous is central to efforts to expand dairy industries, favouring consumers and large dairying companies at the expense of small farms and farm animals. Much more work is needed to track the socioecological impacts of the transition in the Global North and South from distributed small scale farming systems to larger intensified production systems where the livelihoods and wellbeing of farmers, farm workers and farm animals are given appropriate consideration (Steenveld et al. 2012).

Growing awareness of the ecological impacts of dairy

It is increasingly recognised that the global dairy sector has an important role to play in the reduction of global emissions, being a significant contributor of greenhouse gasses, mostly through methane released through eructation, but also through land use change, refrigeration, transport and various other sources (Bar-On et al. 2018 ). The ecological impacts of animal agriculture are well documented with livestock industries also associated with land degradation due to overgrazing, soil erosion and salinisation, deforestation, biodiversity loss, and the contamination of surface and groundwater (Saari et al. 2020). The findings of the UN Food and Agriculture Organisation’s (2006) controversial and ground breaking report Livestock’s Long Shadow first raised the alarm at a global scale and have been bolstered by studies ever since (e.g. Willet et al. 2019). Poore and Nemeck (2018, p. 4), for example, found that even the lowest-impact animal products exceed the environmental impacts of vegetable-based proteins, to the extent that meat, aquaculture, eggs, and dairy use ~ 83% of the world’s farmland, contribute 56–58% of food-related emissions, but provide only 37% of protein intake. These and similar findings are placing pressure on dairy industries to lower emissions and develop more sustainable systems. The most recent Sixth Assessment Report by the IPCC (MassonDelmotte et al. 2021 ) notes substantive increases in methane emissions, with animal agricultural being one of the largest sources.

Research into enteric fermentation, the metabolic process that creates methane in cattle rumen, has targeted the digestive system of cattle to limit the production of methane. Despite thirty years of experiments however, improvements have been minimal and inconsequential when compared with the increasing size of the global herd (McGregor et al. 2021 ). Lively cattle bodies have resisted technological control. Even if much touted but somehow eternally immanent methane mitigating “breakthroughs” are achievable at scale, the ever-increasing demand, production and wastage of food that is part and parcel of the industrial food system (Ormond 2020 ) means that the raft of other environmental problems associated with dairy would remain. The ongoing expansion of the dairy industry will exasperate pollution issues from acidification to eutrophication on land and freshwater systems (Poore and Nemecek 2019; Rotz 2018 ; Fiel et al. 2020 ), as well as the displacement of natural carbon sinks (Harwatt et al. 2019 ) if current production and consumption trajectories persist. While there are efforts to price the environmental and social externalities of dairy to provide a fairer price and contribute to climate change mitigation (Pieper et al. 2020 ) there are also clear limits to this approach (see McAfee 1999 ).

Zafrilla et al. ( 2020 ) reflected on recent reports by the IPCC to argue that livestock production is being positioned as the subject of new forms of climate governance, or as Ormond ( 2020 , p. 163) suggests “corporate carbon commitments” are being redirected to farm level. For example, climate friendly(er) dairy will rely on improvements in cattle breeds and feed (Wankar et al. 2021 ) and improvements in animal health to minimise “wastage” (Mylan et al. 2019 ). However, each of these changes come with their own costs and challenges. For example, some forms of seaweed have been identified as potential feed additives that can reduce methane emissions (Kinley et al. 2020 ). In addition to reducing biogenic methane, the cultivation of seaweed could have net benefits for local labour forces and supporting regional economies (Kinley et al. 2020 ). However, like any intensive production system, this raises questions about the sustainability of large-scale aquaculture, as the cultivation of seaweed for the global meat and dairy cattle herd of over a billion animals will invariably have negative impacts on marine ecosystems (Hasselström et al. 2018 ). The logistics appear challenging at the very least.

Further case studies and empirical research that examines the impacts of that climate mitigation strategies may have upon human and non-human stakeholders is needed to envision what climate friendly cattle may look like in the future (see Ormond 2020 ). For example, if feed additives are a requirement for low emissions dairy production this is likely to increase the costs of production, favouring larger players over smaller ones and further threaten the viability of small farms. In contrast there is some promising work on agro-ecology and regenerative farming being promoted by institutions like the FAO that recasts well managed cattle as assets in the fight against climate change and ecological degradation (for example, see Teague and Kreuter 2020 ). Agroecology principles as defined by the FAO aim to include social values in conjunction with environmental practices that reflect “dignity, equity, inclusion and justice, associated with gender and intergenerational equality and access to decent jobs” (Barrios et al. 2020 , p. 236) and tend to favour the more traditional small scale family farms still prevalent in the Global South. While interest in this area is growing to counter the “monocultures of industrial agriculture” and help small scale farms to prosper (Altieri et al. 2015 , p. 874), it has yet to attract the mass investment required at sufficient scale to counter opposing processes favouring intensification of production.

For some, promissory narratives (Sexton et al. 2019 ) of low emissions cattle through technological or agricultural fixes are a bridge too far, heightening the need for systemic shifts towards plant-based proteins as a replacement for animal-based protein. Rather than being a radical idea the “societal grand challenge” of moving away from or limiting animal-based food systems (see Mylan et al. 2021) is being echoed in major intergovernmental reports, including the IPCC Special Report on Climate Change and Land (Mbow et al. 2019 ) and the EAT-LANCET Commission (Willett et al. 2019 ), as well as the earlier UN Environment Programme report (Hertwich et al. 2010 , p. 82) which argued for a substantial reduction of animal products in human diets in order to lessen the negative environmental impacts from agriculture more broadly. Dairy industries need to develop much more sustainable production processes if they are to mitigate growing consumer concerns about the environmental impacts of the industry.

Alternative milk disruptions

Alternative proteins, in the form of plant-based milks and the gradual development of synthetic milks (grown from fermentation techniques and/or animal cells) are emerging as a fundamental disruption to conventional animal milk production and consumption. Although milks such as soy and nut-milks have had a role throughout human history (Valenze 2011 ), the popularity of these products has increased in volume and expanded in range in recent times driven by consumers who are motivated by both ecological and health concerns (Lonnie et al. 2018 ). This change in consumer preferences is particularly evident in the Global North (see Stokel-Walker 2018 ; Franklin-Wallis 2019 ; Mintel 2019 ). Lonkila and Kaljonen ( 2021 ) argue that the future viability of the global dairy industry is contingent on the attention paid to the “entangled changes” of food production, technological development and consumer demands. Demographics play a role in driving these changes with Stewart et al. ( 2020 ) finding that the consumption of dairy milk in the US drops off steadily with age (Moshfegh et al. 2019). Stokel-Walker ( 2018 ) refers to this process as older consumers “aging out of the market”, while younger consumers are also shifting towards dairy alternatives. McCarthy et al.’s ( 2017 ) US based study found that animal welfare and environmental concerns tend to be primary drivers as to why people might purchase alternative milk over cow’s milk. In their research, they found that the main reasons consumers drink milk is out of habit or “for the flavour” rather than its nutritional quality. Debates around the nutritional properties of milk are out of scope for this review but are more questioned than at any time in the past (for example, see Michaëlsson et al. 2014 ; Aune 2015; Jakobsen et. al 2021). We discuss each form of alternative milk below.

Plant-based milk

Plant-based foods and proteins have become a focal point in the pursuit of sustainability goals (Aschemann-Witzel et al. 2020 ). Sales of plant-based milks are on the rise in the Global North, contributing to a decline in per capita consumption of dairy milk in some countries, including the US (Stewart et al. 2020 ) where dairy milk sales in the US fell to $12 billion in 2019 from $15 billion in 2015, resulting in some large American dairy producers filing for bankruptcy (Garabito 2020 ). Neo and Lim ( 2021 ) found that interest in alternative protein production and consumption were creating opportunities for more localised production in Asia, driven in part by a push for more nutritious “immunity-boosting” products in countries such as China. The OECD–FAO ( 2020 ) report on global dairy and agriculture argues that plant-based dairy substitutes are growing in popularity due to consumer awareness around lactose intolerance, and the health and environmental impact of dairy products (see also Mylan et al. 2019 ). Business opportunities for plant-based products are viewed as positive (Acschmann-Witzel et al. 2020) and are now also being pursued by some existing dairy companies around the world. For example, Danone acquired the plant-based foods company WhiteWave in 2017, which they note was a “strategic move towards meeting consumer expectations for healthier and sustainable choices… enriching our portfolio and complimenting dairy fermented products” (Danone 2021 ). Early adopters of this trend are set to increase sales and production outputs as the increase in demand for plant-based alternatives continues to reconfigure the market.

The interest in plant-based milks derives from a number of negative associations with dairy relating to health (Clay et al. 2020a ), environmental impacts (see Willet et al. 2018; Springmann et al. 2018 ) and animal welfare, particularly in intensive systems where there is a “perceived disconnect from naturalness” (Beaver et al. 2020 , p. 5749). Land use change from pasture to crops to produce plant-based milks is a growing possibility on the horizon (Philippidis et al. 2021 ) if novel dietary patterns such as veganism within Western food culture becomes more mainstream (Chiorando 2018 ). However, a widespread transition to plant-based milk production remains distant and faces many socio-cultural, economic and political hurdles which beckons research from both the physical and social sciences in order to fully understand the socioecological ramifications of such a shift (Philippidis et al. 2021 ). For example, dairy industries across North America, Europe and Australia are engaging in contests over labelling animal-free alternatives such as milk, butter and cheese (Sexton et al. 2019 ). In the US, calls for the reintroduction of the “Dairy Pride Act” have been made to protect dairy industries from plant-based alternatives by claiming milk can only be made by animals (Keller and Heckman LLP 2019 ). Alternative milk brands in the European Union face a ban on using terms or imagery on packaging which refer to or evoke dairy products (Bonadio and Borghini 2021 ). This is positioned as a move to avoid confusion for consumers at the supermarket, however such strategies clearly reflect the interests of dairy industries keen to protect their markets. More research is needed on the potential growth of plant-based alternatives and what contribution they may make to food transitions (Mylan et al. 2019 ; Lonkila and Kaljonen 2021 ).

Synthetic milk

Synthetic milks grown through cellular agriculture (milk that shares the same biochemical make up on animal milk but produced without animal bodies) are emerging as an additional competitor to animal-based milks. Cellular agriculture is an emergent field in which agricultural products—most typically animal-derived agricultural products—are produced through processes operating at the cellular level, as opposed to (typically farm-based) processes operating at the whole organism level (Stephens 2020 ). Cellular agriculture can be defined as “attempts to sustainably supplant animal products with biomass cultured from cells” in-turn creating openings for new food production and novel economic geographies (Jönsson 2020 , p. 922). This new form of food has attracted significant investment from venture-capitalists, particularly concentrated in the Silicon Valley region of San Francisco (Sexton 2020 ) but is also being developed in many richer parts of the world including Israel, Australia and Europe. The US-based company Perfect Day has recently partnered with the company Brave Robot to create the world’s first animal-free dairy ice creams (Starostinetskaya 2021 ). They market their product by claiming cow’s milk ice cream to be “tasty, but unsustainable”, plant-based ice cream as “more sustainable, but not tasty” and their product as “both sustainable AND tasty” (Brave Robot 2021 ). Unlike synthetic meat which faces difficulties in matching the complexity and textures of different meat products, synthetic milk is likely to be indistinguishable from dairy milk due to its liquid form. If it can be produced more cheaply than dairy milk the potential for a relatively rapid change in the dairy industry brought on by cellular agriculture is high. However, at present, the technology is still evolving and the scalability of cellular milk is a challenge (Pandya 2016 ). Reality has not matched the promises envisioned by innovators in the alternative protein sector thus far.

If synthetic milk can replace dairy as an ingredient in the industrial food processing sector (von Massow and Gingerich 2019 ) this could present significant challenges for large-scale producers who depend on the exportability of powdered milk products. In their analysis of the possibilities offered by synthetic milks, Jönsson et al. ( 2019 ) characterise these novelties as “post-animal products” which “carry new realities, new ontologies with them” (Mol as cited in Jönsson et al. 2019 , p. 72). These new forms of food appear better for animal welfare on the basis that there are no livestock animals harmed in the making (synthetic milk can be produced from yeast). Thus, the creation of cellular agriculture and synthetic milks offer the possibility of unfettered production of animal products without conventional spatial constraints and welfare concerns (Jönsson 2020 ), as no animal bodies are concealed or abstracted in the production of milk (Leroy et al. 2020 ). These disruptions in the dairy sector may steer humanity towards radically different food systems (Leroy et al. 2020 ) where synthetic milks compete with traditional dairy. A recent report into the future of dairy by think tank Rethinkx (Tubb and Seba 2019 ) argued that by 2030, new fermentation industries could create up to 700,000 jobs in the US alone. However, Lonkila and Kaljonen ( 2021 , p. 10) warn that synthetic meat and milk alternatives are entangled in capital-intensive agriculture and may further the unequal distribution of protein-rich diets across spaces. As such, alternative proteins do not necessarily challenge corporatisation, homogenisation or consider questions of justice within global food production and consumption (for humans, non-humans and environments), instead they may represent a new stage of consolidation that further marginalises low tech dairy systems. Capital intensive synthetic milk production could eventually further displace many people from the global dairy sector, albeit with potential environmental and animal welfare gains. However, with these new technologies, it may become a possibility that small scale, independently owned breweries could be rolled out in ways that fracture current consolidation processes and empower animal-less local producers in new and interesting ways.

Other animal milks

In addition to plant-based and synthetic milks, other animal milks are, in some contexts, being developed to compete with dairy milk production. On smaller scales, Numpaque et al. (2020) find that for different regions of the world, other animal species such as mare, donkey, yak, reindeer, camel and llama have an important share in milk consumption. At present, world milk production is estimated as 81% cow milk, 15% buffalo milk, and 4% total for other animal milks (OECD–FAO 2020 ). In their review of trends in the dairy sector, Pulina et al. (2020) found that within the last 50 years, sheep and goat milk production has more than doubled and is expected to increase up to 26% for sheep milk and 53% for goat milk by 2030. Miller and Lu ( 2019 ) find that rising consumer demand, strong prices, and climate change are influential factors for the uptake in new goat milk industries in countries such as New Zealand, China and the US. Goat milk has been found to be less allergenic, contain more nutritional benefits than plant-based alternatives (Park 2021 ) and softer gastric digestion than other non-cattle milks (Roy et al. 2020 ). Additionally, the production of small ruminant milks has been suggested as more environmentally friendly and socially appropriate for some rural communities (Pulina et al. 2020). At present, the upscaling of these industries faces barriers as Vouraki et al. ( 2020 ) find that sector lacks the professionalisation, management training and supply chain integration that cow dairy milk has, which results in varied levels of productivity. It is also questionable if the intensification such scaling up would require is desirable for people, animals or the planet.

In this section we look across the four megatrends to reflect on emerging socioecological challenges for dairy industries. One of the most striking trends is the shift in the volume of global dairy production and consumption from North to South. While Northern markets are saturated with milk, there is room for immense growth in parts of the Global South. This creates opportunities for new jobs in the dairy sector and promises nutritional benefits for under-nourished human communities, as long as they can access affordable milk products. The geographic expansion of dairy is being driven by large multinational companies who are investing in more intensive forms of farming. This includes automated milking systems and more confined animal production systems that make milk faster and cheaper, by slashing labour costs and maximising bodily production. Dairying is becoming more homogenous and placeless as it adapts to increasingly stringent industry standards oriented around consumer safety and risk management. Hence the form of dairy expansion that is likely to take place in new areas of the Global South, is more mechanised, corporate and standardised than what has occurred in the past.

While the global growth of dairy is often positioned as a positive outcome for food security and economies, replicating older mythologies about progress and modernisation, our analysis suggests such narratives should be viewed with caution. The literature tends to emphasise the productivity and economic gains for economies and consumers but there is a dearth of work analysing the social costs of dairy farming that focuses on the welfare of humans and non-humans. It is evident, for example, that the corporatisation and intensification of dairy production favours larger companies over small dairy producers. Further mechanisation of dairy production raises questions about the size and longevity of the dairy labour force and is likely to exacerbate the already established trend of pushing smaller dairy milk producers out of competitive markets. In addition, if dairy production is predicted to grow significantly in the Global South over the next decade (OECD–FAO 2021 ), this raises concerns about where the land and resources to enable such an increase is to come from. It is likely that land use pressures will increase the risk of land use conflicts and deforestation, as even intensive dairy farming still requires extensive feed production systems. Dairy cattle require a significant amount of land and resources for the volume of food produced. For example, 1 l of cow’s milk can use up to 1020 l of water throughout the whole process (Rotz 2018 ). It is likely many of the environmental pressures associated with dairy in the Global North will be replicated or intensified. particularly where environmental regulations are lax, in the South, including river and groundwater pollution, greenhouse gas emissions and soil degradation.

As the environmental costs of dairy production become more well known the pressure on smallholders is likely to increase as societies seek to minimise impacts. Expectations for low emissions food products are increasing and may eventually result in regulations requiring feed additives or vaccinations to reduce methane emissions. While larger businesses are likely to be able to absorb these costs, environmental regulations may add to the challenges faced by smallholder farmers. There is also the possibility for bespoke markets to evolve that support small holder farms employing regenerative or agro-ecological principles. However, the general trend is towards intensification or production and more research is needed to fully understand the implications of intensification, standardisation and regulations on human and non-human lives (Holloway and Bear 2017 ). Currently, it seems that many of the benefits of expansion are likely to be captured by large multinational companies, but the immediate social and environmental costs are to be felt locally. As such, many rural communities risk being disadvantaged by such a transition without sufficient government protections. Alternatively, as Weis ( 2013 ) reminds us, there is nothing inevitable or even necessarily desirable about ever-expanding animal-based diets and production systems, particularly for regions such as Asia, where a large proportion of the population are historically lactose intolerant (Valenze 2011 ). At a global scale the climate impacts of dairy production are significant and any increase in dairy cattle in the Global South should be at least matched by decreases of dairy cattle in the Global North. Efforts to expand dairy as the world struggles with global heating is irresponsible and goes against calls for richer countries to “declare a timeframe for peak livestock” after which countries steadily decrease livestock numbers in order to pursue global climate goals (Harwatt et al. 2019 , p. 9).

The world seems a long way from this sort of governmental intervention and so, in the absence of industry-led limits on the global herd, consumers and food tech investors are taking their own action through alternative milk products. Plant and synthetic milks mimic dairy milk in terms of colour, texture, consistency, and taste while at the same time, distancing the product from the unfavourable aspects of dairy, from animal welfare through to health and environmental concerns. Plant-based milks have successfully captured parts of the market and synthetic milks show as yet unrealised promise to make a large impact. However, by mimicking milk, both approaches subtly reinforce dairy milk (and animal products in general) as the norm for modern diets (Lonkila and Kaljonen 2021 ). A critical question for alternative milks is whether replacing one form of industrial production (animal-based dairy) with another (plant and cellular-based dairy) will be socially and environmentally beneficial. Mylan et al. ( 2019 ) argue that alternative milks and their functioning within the food system in relation to the organisation of markets and consumption remains largely unchanged. Additionally, Sexton et al. ( 2019 ) suggest that upscaling alternative proteins (and other animal protein analogues) takes society further away from cultivating more localised food systems based on care and trust. Addressing issues of sustainability through alternative dairy may have some environmental and animal welfare benefits but may accelerate trends of corporatisation and centralised control of food systems, with potentially devastating impacts for small farmers. Such innovations risk merely changing the components of dairy systems (inputs from plants rather than animals) while extending corporate control over land and labour. The social costs of transitioning from dairy milk to plant-based or synthetic milks would be immense for rural communities and as such requires much more research to explore the socioecological dimensions of transitions away from animal-based dairy systems and how, and if, such transitions can be done in just and fair ways.

We have identified four megatrends affecting the global dairy sector and highlighted key challenges for the future. The impacts of shifting geographies, intensification, ecological pressures and the possibilities offered by milk alternatives are creating openings for interdisciplinary scholarship to engage with the under-researched impacts of these trends. Such research should recognise the vitality and agency of cattle and other actors within dairy systems, and that the expansion of dairy industries is not just an economic process, but one that is embedded with more-than-human relations (Collard and Dempsey 2013 ). Cattle not only require food, water, land and labour to produce milk, but they increasingly require robots, quality standards, methane mitigation technologies, intensive farming, investment and international markets if they are to survive. It is the liveliness of cattle that has shaped these relations, a liveliness that dairy industries will never fully control or contain and is resulting in the megatrends we have identified here. While some megatrends reflect an enthusiastic embrace and expansion of these increasingly corporatized assemblages, others reflect concerns about their destructive socioecological impacts, resulting in a growing market for dairy alternatives. There is a need for more critical case study research that focuses on the complex impacts dairying, and dairy alternatives, are having on place, people and cattle.

Our review suggests that the future of dairy is not clear nor uncontroversial. The mythology that milk is unquestionably good and universally beneficial is not borne out by this review and the almost teleological assumption that dairy will simply roll out across the planet to benefit all deserves careful scrutiny to assess its true costs. If dairy is to live up to its promises, much more attention needs to be directed to maximising and broadening the socioecological benefits of the industry, minimising the human and non-human costs, including those inflicted on cattle, and limiting its contributions to global environmental change. With some trends working against these goals, the social license of dairy is likely to erode in mature markets, creating further openings for milk alternatives, each of which comes with its own set of challenges. While dairy is likely to continue expanding in the immediate future, the megatrends and socioecological challenges we have identified here are substantial and suggest its medium-term future trajectories are much less certain.

For this paper, the term ‘dairy’ refers to bovine milk in its whole form, as well as milk powder, butter, cheese, yoghurt, ice-cream, cream and any other industrially processed foods that may contain milk by-products (often in the form of milk powder).

There are articles referred to throughout this review that have been published outside of this timeframe but nonetheless contribute to the understanding of how the global dairy sector has evolved over time.

This point does not include other types of animal milks such as camel, mare, sheep or goat, which continue to be a vital food source for many rural and nomadic cultures.

It is important to note that figures about global dairy consumption may mask the vast differences across regions.

Anderson, V.D. 2004. Creatures of Empire: How domestic animals transformed early America . Oxford: Oxford University Press.

Book   Google Scholar  

Altieri, M.A., C.I. Nicholls, A. Henao, and M.A. Lana. 2015. Agroecology and the design of climate change resilient farming systems. Agronomy for Sustainable Development 35 (3): 869–890. https://doi.org/10.1007/s13593-015-0285-2 .

Article   Google Scholar  

Aune, D., D.A. Navarro Rosenblatt, D.S. Chan, A.R. Vieira, R. Vieira, D.C. Greenwood, L.J. Vatten, and T. Norat. 2015. Dairy products, calcium, and prostate cancer risk: A systematic review and meta-analysis of cohort studies. The American Journal of Clinical Nutrition 101 (1): 87–117. https://doi.org/10.3945/ajcn.113.067157 .

Aschemann-Witzel, J., R.F. Gantriis, P. Fraga, and F.J.A. Perez-Cueto. 2020. Plant-based food and protein trend from a business perspective: Markets, consumers, and the challenges and opportunities in the future. Critical Reviews in Food Science and Nutrition . https://doi.org/10.1080/10408398.2020.1793730 .

Bai, Z., M.R. Lee, L. Ma, S. Ledgard, G.L. Velthof, W. Ma, M. Guo, M. Zhao, Z. Wei, S. Li, S. Liu, X. Havlík, P. Luo, J. Hu, and F. Zhang. 2018. Global environmental costs of China’s thirst for milk. Global Change Biology 24 (5): 2198–2211. https://doi.org/10.1111/gcb.14047 .

Barua, M. 2014. Volatile ecologies: Towards a material politics of human–animal relations. Environment and Planning A 46 (6): 1462–1478. https://doi.org/10.1068/a46138 .

Bar-On, Y.M., R. Phillips, and R. Milo. 2018. The biomass distribution on Earth. Proceedings of the National Academy of Sciences of USA 115 (25): 6506–6511. https://doi.org/10.1073/pnas.1711842115 .

Barrios, E., B. Gemmill-Herren, A. Bicksler, E. Siliprandi, R. Brathwaite, S. Moller, C. Batello, and P. Tittonell. 2020. The 10 elements of agroecology: Enabling transitions towards sustainable agriculture and food systems through visual narratives. Ecosystems and People (abingdon, England) 16 (1): 230–247. https://doi.org/10.1080/26395916.2020.1808705 .

Bear, C., and L. Holloway. 2019. Beyond resistance: Geographies of divergent more-than-human conduct in robotic milking. Geoforum 104: 212–221. https://doi.org/10.1016/j.geoforum.2019.04.030 .

Beaver, A., K.L. Proudfoot, and M.A. von Keyserlingk. 2020. Symposium review: Considerations for the future of dairy cattle housing: An animal welfare perspective. Journal of Dairy Science 103 (6): 5746–5758. https://doi.org/10.3168/jds.2019-17804 .

Bonadio, E., and A. Borghini. 2021. Vegan ‘dairy’ products face EU ban from using milk cartons and yoghurt pots—And UK could be next. In Brave New Europe , 24 January. https://braveneweurope.com/enrico-bonadio-andrea-borghini-vegan-dairy-products-face-eu-ban-from-using-milk-cartons-and-yoghurt-pots-and-uk-could-be-next . Accessed 20 March 2021.

Bosc, P.M., J.M. Sourisseau, P. Bonnal, P. Gasselin, É. Valette, and J.F. Bélières. 2018. Diversity of family farming around the world existence, transformations and possible futures of family farms . Dordrecht: Springer.

Brave Robot. 2021. Brave Robot. https://braverobot.co/ . Accessed 8 Feb 2021.

Briam, R., M.E. Walker, and E. Masanet. 2015. A comparison of product-based energy intensity metrics for cheese and whey processing. Journal of Food Engineering 151: 25–33. https://doi.org/10.1016/j.jfoodeng.2014.11.011 .

Britt, J., R. Cushman, C. Dechow, H. Dobson, P. Humblot, M. Hutjens, G. Jones, P. Ruegg, I. Sheldon, and J. Stevenson. 2018. Invited review: Learning from the future—A vision for dairy farms and cows in 2067. Journal of Dairy Science 101 (5): 3722–3741. https://doi.org/10.3168/jds.2017-14025 .

Challis, C., M. Tierney, A. Todd, and E. Wilson. 2017. Human factors in dairy industry process control for energy reduction. Journal of Cleaner Production 168: 1319–1334. https://doi.org/10.1016/j.jclepro.2017.09.121 .

Chiorando, M. 2018. 2019 will be year of the vegan’ according to the economist. Plant Based News , 26 December. https://plantbasednews.org/culture/2019-year-vegan-the-economist . Accessed 2 July 2021.

Clarke, C., and D. Knights. 2021. Milking it for all it’s worth: Unpalatable practices, dairy cows and veterinary work? Journal of Business Ethics . https://doi.org/10.1007/s10551-020-04666-3 .

Clay, N., and K. Yurco. 2020. Political ecology of milk: Contested futures of a lively food. Geography Compass 14 (8): 12497. https://doi.org/10.1111/gec3.12497 .

Clay, N., A.E. Sexton, T. Garnett, and J. Lorimer. 2020a. Palatable disruption: The politics of plant milk. Agriculture and Human Values 37 (4): 945–962. https://doi.org/10.1007/s10460-020-10022-y .

Clay, N., T. Garnett, and J. Lorimer. 2020b. Dairy intensification: Drivers, impacts and alternatives. Ambio 49 (1): 35–48. https://doi.org/10.1007/s13280-019-01177-y .

Cogato, A., M. Brščić, H. Guo, F. Marinello, and A. Pezzuolo. 2021. Challenges and tendencies of automatic milking systems (AMS): A 20-years systematic review of literature and patents. Animals (basel). 11 (2): 356. https://doi.org/10.3390/ani11020356 .

Collard, R.C., and J. Dempsey. 2013. Life for sale? The politics of lively commodities. Environment and Planning A 45 (11): 2682–2699. https://doi.org/10.1068/a45692 .

Dairy Industries International. 2020. Yili rises to top five in 2020 global dairy top 20 . Dairy Industries International, 7 September. https://www.dairyindustries.com/news/35223/yili-rises-to-top-five-in-2020-global-dairy-top-20 . Accessed 4 Feb 2021.

Danone. 2021. Essential Dairy and Plant-based products . Danone. https://www.danone.com/brands/dairy-plant-based-products.html . Accessed 4 Feb 2021

Douphrate, D.I., R.G. Hagevoort, M.W. Nonnenmann, P. Kolstrup, C.L. Reynolds, M. Jakob, M. Kinsel, and M. 2013. The dairy industry: A brief description of production practices, trends, and farm characteristics around the world. Journal of Agromedicine 18 (3): 187–197. https://doi.org/10.1080/1059924X.2013.796901 .

Delgado, C.L. 2003. Rising consumption of meat and milk in developing countries has created a new food revolution. The Journal of Nutrition 133 (11): 3907S-3910S. https://doi.org/10.1093/jn/133.11.3907S .

Ding, H., Y. Fu, L. Zheng, and Z. Yan. 2019. Determinants of the competitive advantage of dairy supply chains: Evidence from the Chinese dairy industry. International Journal of Production Economics 209: 360–373. https://doi.org/10.1016/j.ijpe.2018.02.013 .

FAO. 2006. Livestock’s long shadow: Environmental issues and options. United Nations Food and Agriculture Organisation of the United Nations. https://www.fao.org/3/a0701e/a0701e00.html . Accessed 20 Dec 2020.

FAO. 2019. Climate change and the global dairy cattle sector . United Nations Food and Agriculture Organisation . https://www.fao.org/3/CA2929EN/ca2929en.pdf . Accessed 20 May 2021.

FAO. 2020. Diary market review . United Nations Food and Agriculture Organisation. http://www.fao.org/3/ca8341en/CA8341EN.pdf . Accessed 18 Dec 2020.

FAO, IFAD, UNICEF, WFP and WHO. 2020. The state of food security and nutrition in the world 2020 . Food and Agriculture Organisation of the United Nations. https://www.fao.org/documents/card/en/c/ca9692en . Accessed 21 Jan 2021.

Fiel, A.A., D. Schreiber, C. Haetinger, A.M. Haberkamp, J.I. Kist, C. Rempel, A.E. Maehler, M.C. Gomes, and G.R. da Silva. 2020. Sustainability in the dairy industry: A systematic literature review. Environmental Science and Pollution Research International 27 (27): 33527–33542. https://doi.org/10.1007/s11356-020-09316-9 .

Franklin-Wallis, O. 2019. White gold; the unstoppable rise of alternative milks. The Guardian , 29 January. https://www.theguardian.com/news/2019/jan/29/white-gold-the-unstoppable-rise-of-alternative-milks-oat-soy-rice-coconut-plant . Accessed 1 July 2020.

Garabito, D. 2020. “Cash Cows”: The growth of plant-based alternatives. McGill Business Review , 11 May 2020. https://mcgillbusinessreview.com/articles/cash-cow-the-growth-of-plant-based-alternatives . Accessed 31 Jan 2021.

Gauly, M., H. Bollwein, G. Breves, K. Brügemann, S. Dänicke, G. Daş, J. Demeler, H. Hansen, J. Isselstein, S. König, M. Lohölter, M. Martinsohn, U. Meyer, M. Potthoff, C. Sanker, B. Schröder, N. Wrage, B. Meibaum, G. von Samson-Himmelstjerna, H. Stinshoff, and C. Wrenzycki. 2013. Future consequences and challenges for dairy cow production systems arising from climate change in Central Europe—A review. Animal (cambridge, England) 7 (5): 843–859. https://doi.org/10.1017/S1751731112002352 .

GEA Group. 2020. GEA installs largest milking rotary parlor in China for 10,000 cows. Gesellschaft für Entstaubungsanlagen, 13 November, https://www.gea.com/en/news/trade-press/2020/t8900-gea-milking-rotary-parlor-in-china.jsp . Accessed 1 March 2022.

Gianni, M., K. Gotzamani, and F. Vouzas. 2017. Food integrated management systems: Dairy industry insights. The International Journal of Quality and Reliability Management 34 (2): 194–215. https://doi.org/10.1108/IJQRM-05-2015-0076 .

Gillespie, K., and R.C., Collard. 2015. Critical Animal Geographies: Politics, intersections, and hierarchies in a multispecies world , 1st ed. London: Routledge.

Gillespie, K. 2018. The cow with ear tag #1389 . Chicago: The University of Chicago Press.

Gillespie, K. 2021. The afterlives of the lively commodity: Life-worlds, death-worlds, rotting-worlds. Environment and Planning. A 53 (2): 280–295. https://doi.org/10.1177/0308518X20944417 .

Hajkowicz, S. 2015. Global megatrends: Seven patterns of change shaping our future . Clayton South: CSIRO Publishing.

Haraway, D.J. 2003. The companion species manifesto: Dogs, people, and significant otherness . Chicago: Prickly Paradigm.

Google Scholar  

Harwatt, H., W.J. Ripple, A. Chaudhary, M.G. Betts, and M. Hayek. 2019. Scientists call for renewed Paris pledges to transform agriculture . The Lancet . https://www.thelancet.com/pdfs/journals/lanplh/PIIS2542-5196(19)30245-1.pdf/ . Accessed 27 April 2021.

Hasselström, L., W. Visch, and F., Gröndahl, G.M. Nylund, and H. Pavia. 2018. The impact of seaweed cultivation on ecosystem services—A case study from the west coast of Sweden. Marine Pollution Bulletin 133: 53–64. https://doi.org/10.1016/j.marpolbul.2018.05.005 .

Hertwich, E., E. van der Voet, S. Suh, A. Tukker, M. Huijbregts, P. Kazmierczyk, M. Lenzen, J. McNeely, and Y. Moriguchi. 2010. Accessing the environmental impacts of consumption and production . United Nations Environment Program. https://www.resourcepanel.org/reports/assessing-environmental-impacts-consumption-and-production . Accessed 10 June 2021.

Hjalsted, L., A. Laurent, M.M. Anderson, K.H. Olsen, M. Ryberg, and M. Hauschild. 2020. Sharing the safe operating space: Exploring ethical allocation principles to operationalize the planetary boundaries and assess absolute sustainability at individual and industrial sector levels. Journal of Industrial Ecology . https://doi.org/10.1111/jiec.13050 .

Holloway, I., and C. Bear. 2017. Bovine and human becomings in histories of dairy technologies: Robotic milking systems and remaking animal and human subjectivity. BJHS Themes 2: 215–234. https://doi.org/10.1017/bjt.2017.2 .

Jacobs, J., and J. Siegford. 2012. Invited review: The impact of automatic milking systems on dairy cow management, behavior, health, and welfare. Journal of Dairy Science 95 (5): 2227–2247. https://doi.org/10.3168/jds.2011-4943 .

Jakobsen, M.U., E. Trolle, M. Outzen, H. Mejborn, M.G. Grønberg, C.B. Lyndgaard, A. Stockmarr, S.K. Venø, and A. Bysted. 2021. Intake of dairy products and associations with major atherosclerotic cardiovascular diseases: A systematic review and meta-analysis of cohort studies. Scientific Reports 11 (1): 1303–1328. https://doi.org/10.1038/s41598-020-79708-x .

Jönsson, E., T. Linné, and A. McCrow-Young. 2019. Many meats and many milks? The ontological politics of a proposed post-animal revolution. Science as Culture 28 (1): 70–97. https://doi.org/10.1080/09505431.2018.1544232 .

Jönsson, E. 2020. On breweries and bioreactors: Probing the “present futures” of cellular agriculture’. Transactions of the Institute of British Geographers 45 (4): 921–936. https://doi.org/10.1111/tran.12392 .

Keller and Heckman LLP. 2019. Dairy Pride Act’ Introduced Again. The National Law Review , 19 March. https://www.natlawreview.com/article/dairy-pride-act-introduced-again . Accessed 10 March 2021.

Kinley, R.D., G. Martinez-Fernandez, M.K. Matthews, R. de Nys, M. Magnusson, and N.W. Tomkins. 2020. Mitigating the carbon footprint and improving productivity of ruminant livestock agriculture using a red seaweed. Journal of Cleaner Production 259: 120836. https://doi.org/10.1016/j.jclepro.2020.120836 .

Knips, V. 2005. Developing countries and the global dairy sector part I global overview . Pro-Poor Livestock Policy Initiative . https://www.fao.org/3/bp204e/bp204e.pdf . Accessed 10 Feb 2021.

Kotsanopoulos, K.V., and I.S. Arvanitoyannis. 2017. The role of auditing, food safety, and food quality standards in the food industry: A review. Comprehensive Reviews in Food Science and Food Safety 16 (5): 760–775. https://doi.org/10.1111/1541-4337.12293 .

Ladha-Sabur, A., S. Bakalis, P.J. Fryer, and E. Lopez-Quiroga. 2019. Mapping energy consumption in food manufacturing. Trends in Food Science and Technology 86: 270–280. https://doi.org/10.1016/j.tifs.2019.02.034 .

Latour, B. 1999. Politics of nature . Cambridge: Harvard University Press.

Ledman, M., and S. van Battum. 2020. Global Dairy Top 20. RaboBank. https://research.rabobank.com/far/en/sectors/dairy/dairy_top_20_2020.html . Accessed 4 Feb 2021.

Leroy, F., A.H. Hite, and P. Gregorini. 2020. Livestock in evolving foodscapes and thoughtscapes. Frontiers in Sustainable Food Systems . https://doi.org/10.3389/fsufs.2020.00105 .

Lonkila, A., and M. Kaljonen. 2021. Promises of meat and milk alternatives: An integrative literature review on emergent research themes. Agriculture and Human Values 38 (3): 625–638. https://doi.org/10.1007/s10460-020-10184-9 .

Lonnie, M., E. Hooker, J.M. Brunstrom, B.M. Corfe, M.A. Green, A.W. Watson, E.A. Williams, E.J. Stevenson, S. Penson, and A.M. Johnstone. 2018. Protein for life: Review of optimal protein intake, sustainable dietary sources and the effect on appetite in ageing adults. Nutrients 10 (3): 360. https://doi.org/10.3390/nu10030360 .

MassonDelmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou. 2021. IPCC 2021: Summary for policymakers. In Climate change 2021: The physical science basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change . Cambridge: Cambridge University Press.

Mbow, C., C. Rosenzweig, L.G. Barioni, T.G. Benton, M. Herrero, M. Krishnapillai, E. Liwenga, P. Pradhan, M.G. Rivera-Ferre, T. Sapkota, F.A. Tubiello, and Y. Xu. 2019. Food security. In Climate change and land: An IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems . Intergovernmental Panel on Climate Change. https://www.ipcc.ch/srccl/ . Accessed 10 March 2021.

McAfee, K. 1999. Selling nature to save it? Biodiversity and green developmentalism. Environment and Planning d, Society and Space 17 (2): 133–154. https://doi.org/10.1068/d170133 .

McCarthy, K., M. Parker, A. Ameerally, S. Drake, and M. Drake. 2017. Drivers of choice for fluid milk versus plant-based alternatives: What are consumer perceptions of fluid milk? Journal of Dairy Science 100 (8): 6125–6138. https://doi.org/10.3168/jds.2016-12519 .

McGregor, A., L. Rickards, D. Houston, M.K. Goodman, and M. Bojovic. 2021. The biopolitics of cattle methane emissions reduction: Governing life in a time of climate change. Antipode 53 (4): 1161–1186. https://doi.org/10.1111/anti.12714/ .

Michaëlsson, K., A. Wolk, S. Langenskiöld, S. Basu, E. Warensjö Lemming, H. Melhus, and L. Byberg. 2014. Milk intake and risk of mortality and fractures in women and men: Cohort studies. British Medical Journal 349 (1): 6015–6015. https://doi.org/10.1136/bmj.g6015 .

Mittelstaedt, J.D., C.J. Shultz, W.E. Kilbourne, and M. Peterson. 2014. Sustainability as megatrend: Two schools of macromarketing thought. Journal of Macromarketing 34 (3): 253–264. https://doi.org/10.1177/0276146713520551 .

Miller, B.A., and C.D. Lu. 2019. Current status of global dairy goat production: An overview. Asian-Australasian Journal of Animal Science. 32 (8): 1219–1232. https://doi.org/10.5713/ajas.19.025 .

Mintel. 2019 . Milking the vegan trend: A quarter (23%) of brits use plant-based milk. Mintel, 19 July. https://www.mintel.com/press -centre/food-and-drink/milking-the-vegan-trend-a-quarter-23-of-brits-use-plant-based-milk. Accessed 1 July 2021.

Minten, B., Y. Habte, S. Tamru, and A. Tesfaye. 2020. The transforming dairy sector in Ethiopia. PLoS ONE 15 (8): e0237456. https://doi.org/10.1371/journal.pone.0237456 .

Morris, C., M. Kaljonen, L. Aavik, B. Balázs, M. Cole, B. Coles, S. Efstathiu, T. Fallon, M. Foden, E.H. Giraud, M. Goodman, E.H. Kershaw, R. Helliwell, P. Hobson-West, M. Häyry, P. Jallinoja, M. Jones, T. Kaarlenkaski, M. Laihonen, A. Lähteenmäki-Uutela, S. Kupsala, A. Lonkila, L. Martens, R. McGlacken, J. Mylan, M. Niva, E. Roe, R. Twine, M. Vinnari, and R. White. 2021. Priorities for social science and humanities research on the challenges of moving beyond animal-based food systems. Humanities and Social Sciences Communications 8 (1): 1–12. https://doi.org/10.1057/s41599-021-00714-z .

Moshfegh, A.J., A.O. Garceau, E.A. Parker, and J.C. Clemens. Beverage choices among children: What we eat in America, NHANES 2015–2016 . U.S. Department of Agriculture, Agricultural Research Service. https://www.ars.usda.gov/ARSUserFiles/80400530/pdf/DBrief/22_Beverage_choices_children_1516.pdf . Accessed 10 June 2021.

Mylan, J., C. Morris, E. Beech, and F.W. Geels. 2019. Rage against the regime: Niche–regime interactions in the societal embedding of plant-based milk. Environmental Innovation and Societal Transitions 31: 233–247. https://doi.org/10.1016/j.eist.2018.11.001 .

Naisbitt, J. 1984. Megatrends: Ten new directions transforming our lives . London: MacDonald.

Neo, P. and F.Y. Lim. 2021. Six top trends set to impact APAC’s F&B development in 2021—Featuring Mondelez, Chobani, Kirin, Nestle and more. Food Navigator Asia, 4 January. https://www.foodnavigator-asia.com/Article/2021/01/04/Six-top-trends-set-to-impact-APAC-s-F-B-development-in-2021-featuring-Mondelez-Chobani-Kirin-Nestle-and-more . Accessed 19 Feb 2021.

Nestle. 2021. Brands. Nestle. https://www.nestle.com/brands . Accessed 4 Feb 2021.

Oceania Dairy. 2020. Yili Group . Oceania Dairy . https://oceaniadairy.co.nz/yili-group/ . Accessed 4 Feb 2021.

Numpaque, M., T. Şanlı, and E.A. Anli. 2019. Diversity of milks other than cow, sheep, goat and buffalo: In terms of nutrition and technological use. Turkish Journal of Agriculture: Food Science and Technology 7 (12): 2047–2053. https://doi.org/10.24925/turjaf.v7i12.2047-2053.2623 .

OECD–FAO. 2010. Agricultural Outlook 2010 . Paris: OECD Publishing.

OECD–FAO. 2020. OECD–FAO Agricultural Outlook 2020–2029 . Paris: OECD Publishing. https://doi.org/10.1787/aa3fa6a0-en .

OECD–FAO. 2021. Table C.5—World dairy projections: Milk, butter and cheese . OECD–FAO. https://www.oecd-ilibrary.org/agriculture-and-food/world-dairy-projections-milk-butter-and-cheese_0ca74b06-en . Accessed 28 Aug 2021.

Ormond, J. 2020. Geoengineering super low carbon cows: Food and the corporate carbon economy in a low carbon world. Climatic Change 163 (1): 135–215. https://doi.org/10.1007/s10584-020-02766-7 .

Pandya, R. 2016. Developing the animal-free future of dairy. YouTube . https://www.youtube.com/watch?v=wv7gjWg5wTY&t=607s . Accessed 7 Feb 2021.

Park, Y.W. 2021. The impact of plant-based non-dairy alternative milk on the dairy industry. Food Science of Animal Resources 41 (1): 8–15. https://doi.org/10.5851/kosfa.2020.e82 .

Pieper, M., A. Michalke, and T. Gaigler. 2020. Calculation of external climate costs for food highlights inadequate pricing of animal products. Nature Communications 11 (1): 6117–6117. https://doi.org/10.1038/s41467-020-19474-6 .

Philippidis, G., H. Ferrer-Pérez, P. Gracia-de-Rentería, R. M’barek, and A.I. Sanjuán López. 2021. Eating your greens: A global sustainability assessment. Resources, Conservation and Recycling. 168: 105460. https://doi.org/10.1016/j.resconrec.2021.105460 .

Poore, J., and T. Nemecek. 2018. Reducing food’s environmental impacts through producers and consumers. Science (american Association for the Advancement of Science) 360 (6392): 987–992. https://doi.org/10.1126/science.aaq0216 .

Popkin, B.M. 2003. The nutrition transition in the developing world. Development Policy Review 21 (5–6): 581–597. https://doi.org/10.1111/j.1467-8659.2003.00225.x .

Pulina, G., M. Milán, M. Lavín, A. Theodoridis, E. Morin, J. Capote, D. Thomas, A.H. Francesconi, and G. Caja. 2018. Invited review: Current production trends, farm structures, and economics of the dairy sheep and goat sectors. Journal of Dairy Science 101 (8): 6715–6729. https://doi.org/10.3168/jds.2017-14015 .

Raboresearch. 2020. Global dairy top 20 . Rabobank . https://research.rabobank.com/publicationservice/download/publication/token/H5laAEfE5bCRp5mv9cP . Accessed 20 Aug 2021.

Reardon, T., C.B. Barrett, J.A. Berdegué, and J.F. Swinnen. 2009. Agrifood industry transformation and small farmers in developing countries. World Development 37 (11): 1717–1727. https://doi.org/10.1016/j.worlddev.2008.08.023 .

Rohner, P. 2018. Water: A megatrends perspective. In Assessing global water megatrends , 1st ed, eds. A.K. Biswas., C. Tortajada, and P. Rohner, Singapore: Springer.

Rotz, C.A. 2018. Modeling greenhouse gas emissions from dairy farms. Journal of Dairy Science 101 (7): 6675–6690. https://doi.org/10.3168/jds.2017-13272 .

Roy, D., A. Ye, H. Singh, and P.J. Moughan. 2020. Composition, structure, and digestive dynamics of milk from different species-a review. Frontiers in Nutrition (lausanne) 7: 577759. https://doi.org/10.3389/fnut.2020.577759 .

Saari, U.A., C. Herstatt, R. Tiwari, O. Dedehayir, and S.J. Mäkinen. 2021. The vegan trend and the microfoundations of institutional change: A commentary on food producers’ sustainable innovation journeys in Europe. Trends in Food Science and Technology 107: 161–167. https://doi.org/10.1016/j.tifs.2020.10.003 .

Schuster, J.C., H.W. Barkema, A. De Vries, D.F. Kelton, and K. Orsel. 2020. Invited review: Academic and applied approach to evaluating longevity in dairy cows. Journal of Dairy Science 103 (12): 11008–11024. https://doi.org/10.3168/jds.2020-19043 .

Sewell, S. 2021. Small farms vanish every day in America’s dairy land: ‘There ain’t no future in dairy’. The Guardian , 21 July. https://www.theguardian.com/environment/2021/jul/21/small-farms-vanish-every-day-in-americas-dairyland-there-aint-no-future-in-dairy . Accessed 6 Aug 2021.

Sexton, A.E., T. Garnett, and J. Lorimer. 2019. Framing the future of food: The contested promises of alternative proteins. Environment and Planning E, Nature and Space 2 (1): 47–72. https://doi.org/10.1177/2514848619827009 .

Sexton, A.E. 2020. Food as software: Place, protein, and feeding the world Silicon Valley-style. Economic Geography 96 (5): 449–469. https://doi.org/10.1080/00130095.2020.1834382 .

Slaughter, R. 1993. Looking for the real “megatrends.” Futures: the Journal of Policy, Planning and Futures Studies 25 (8): 827–849. https://doi.org/10.1016/0016-3287(93)90033-P .

Springmann, M., M. Clark, D. Mason-D’Croz, K. Wiebe, B.L. Bodirsky, L. Lassaletta, S.J. de Vries, S.J. Vermeulen, M. Herrero, K.M. Carlson, M. Jonell, M. Troell, F. DeClerck, L.J. Gordon, R. Zurayk, P. Scarborough, M. Rayner, B. Loken, J. Fanzo, H.C. Godfray, D. Tilman, J. Rockström, and W. Willett. 2018. Options for keeping the food system within environmental limits. Nature 562 (7728): 519–525. https://doi.org/10.1038/s41586-018-0594-0 .

Starostinetskaya, A. 2021. Worlds first dairy-identical vegan ice cream launches at 5000 stores . VegNews , 5 February. https://vegnews.com/2021/2/dairy-identical-vegan-ice-cream-at-5-000-stores . Accessed 8 Feb 2021.

Steeneveld, W., L. Taue, H. Hogeveen, and A.G.J. Oude Lansink. 2012. Comparing technical efficiency of farms with an automatic milking system and a conventional milking system. Journal of Dairy Science 95 (12): 7391–7398. https://doi.org/10.3168/jds.2012-5482 .

Stephens, E. 2020. Cellular agriculture in the UK: A review. Open Research 5: 12. https://doi.org/10.12688/wellcomeopenres.15685.2 .

Stewart, H., F. Kuchler, J. Cessna, and W. Hahn. 2020. Are plant-based analogues replacing cow’s milk in the American diet? Journal of Agricultural and Applied Economics 52 (4): 1–18. https://doi.org/10.1017/aae.2020.16 .

Stokel-Walker, C. 2018. The irresistible rise of alternative milks like Oatly has dairy farmers freaked. Wired , 22 August. https://www.wired.co.uk/article/non-dairy-milk-alternatives-oatly-soy-oat-rice-vegan . Accessed 12 Feb 2021.

Teague, R., and U. Kreuter. 2020. Managing grazing to restore soil health, ecosystem function, and ecosystem services. Frontiers in Sustainable Food Systems . https://doi.org/10.3389/fsufs.2020.534187 .

Tubb, C., and T. Seba. 2019. Rethinking food and agriculture 2020–2030. RethinkX. https://static1.squarespace.com/static/585c3439be65942f022bbf9b/t/5d7fe0e83d119516bfc0017e/1568661791363/RethinkX+Food+and+Agriculture+Report.pdf . Accessed 2 July 2021.

Turner, J. 2005. A new approach for theoretically integrating micro and macro analysis. In The SAGE handbook of sociology , ed. C. Calhoun, C. Rojek, and B. Turner, 405–422. London: SAGE Publications.

Chapter   Google Scholar  

Valenze, D. 2011. Milk: A local and global history . London: Yale University Press.

Visconti, L.M., Y. Minowa, and P. Maclaran. 2014. Public markets: An ecological perspective on sustainability as a megatrend. Journal of Macromarketing 34 (3): 349–368. https://doi.org/10.1177/0276146714525201 .

von Massow, M., and M. Gingerich. 2019. Lab-grown dairy: The next food frontier . The Conversation , 12 June. https://theconversation.com/lab-grown-dairy-the-next-food-frontier-117963 . Accessed 12 March 2021.

Vouraki, S., I. Skourtis, K. Psichos, W. Jones, C. Davis, M. Johnson, L.R. Rupérez, A. Theodoridis, and G. Arsenos. 2020. A decision support system for economically sustainable sheep and goat farming. Animals (basel) 10 (12): 2421. https://doi.org/10.3390/ani10122421 .

Wankar, A.K., S.N. Rindhe, and N.S. Doijad. 2021. Heat stress in dairy animals and current milk production trends, economics, and future perspectives: The global scenario. Tropical Animal Health and Production 53 (1): 70. https://doi.org/10.1007/s11250-020-02541-x .

Weis, A.J. 2013. The ecological hoof print: The global burden of industrial livestock . London: Zed Books.

Willett, W., J. Rockström, B. Loken, M. Springmann, T. Lang, S. Vermeulen, T. Garnett, D. Tilman, F. DeClerck, A. Wood, M. Jonell, M. Clark, L.J. Gordon, J. Fanzo, C. Hawkes, R. Zurayk, J.A. Rivera, W. De Vries, L. Majele Sibanda, A. Afshin, A. Chaudhary, M. Herrero, R. Agustina, F. Branca, A. Lartey, S. Fan, B. Crona, E. Fox, V. Bignet, M. Troell, T. Lindahl, S. Singh, S.E. Cornell, K. Srinath Reddy, S. Narain, S. Nishtar, and C.J.L. Murray. 2019. Food in the Anthropocene: The EAT–Lancet Commission on Healthy Diets from Sustainable Food Systems. The Lancet (british Edition) 393 (10170): 447–492. https://doi.org/10.1016/S0140-6736(18)31788-4 .

Whatmore, S. 2002. Hybrid geographies: Natures, cultures, spaces . London: Sage.

Zafrilla, J., A. García-Alaminos, and F. Monsalv. 2020. The sustainability challenge of dairy livestock systems. In Sustainable and environmentally friendly dairy farms , ed. S. García-Yuste, 1–17. Cham: Springer.

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Bojovic, M., McGregor, A. A review of megatrends in the global dairy sector: what are the socioecological implications?. Agric Hum Values 40 , 373–394 (2023). https://doi.org/10.1007/s10460-022-10338-x

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SYSTEMATIC REVIEW article

Sustainability of the dairy industry: emissions and mitigation opportunities.

• Department of Animal Science, University of California, Davis, Davis, CA, United States

Dairy cattle provide a major benefit to the world through upcycling human inedible feedstuffs into milk and associated dairy products. However, as beneficial as this process has become, it is not without potential negatives. Dairy cattle are a source of greenhouse gases through enteric and waste fermentation as well as excreting nitrogen emissions through their feces and urine. However, these negative impacts vary widely due to how and what these animals are fed. In addition, there are many promising opportunities for further reducing emissions through feed and waste additives. The present review aims to further expand on where the industry is today and the potential avenues for improvement. This area of research is still not complete and additional information is required to further improve our dairy systems impact on sustainable animal products.

Introduction

Dairy production is considered a major societal asset globally due to its economic and nutritional benefits. In 2019 alone global milk production totaled 851.8 million tons in milk equivalents ( Outlook, 2020 ). This contributes to substantial trade impacts, totaling about 76.7 million tons in 2019, as well as major per capita consumption at about 111.4 kg/year globally ( Outlook, 2020 ). There are over 245 million dairy cows worldwide that on average produce 2,300 kg per year; although average production is less informative as there is such a major disparity between production in different countries ( FAO, 2009 ). This vast amount of milk production has a major global benefit—for human health, society, and the economy. In countries with developing economies livestock serve many purposes including: a source of household income, a financial asset for women, a source of food security, risk management, and a direct link to human health ( Herrero et al., 2013 ). These benefits increase substantially when viewed from a macro lens. Global dairy imports totaled over $42.2 billion in 2014 and global dairy exports expanded 175% from 2005 to 2014 ( Davis and Hahn, 2016 ). There are many dairy commodities being produced and traded as part of these exports with whole milk powder being the highest, followed by skim milk powder, butter, and cheese ( Outlook, 2020 ). India is the largest dairy producer globally, with 22% of global production and 52,841,810 total dairy cattle, the US is second in production, followed by China, Pakistan, and Brazil ( FAO, 1997 ; Knips, 2005 ). While the US may not be the largest global milk producer, the total economic benefit of the dairy industry is substantial, totaling $628.27 billion dollars in 2018 ( O'Keefe, 2018 ). There are currently 9,336,000 dairy cows in the U.S. that on average produce 10,610 kg of milk each year, which amassed to over 99,056,409 kg of milk in 2019 ( USDA, 2020 ). The US dairy sector also generates over 2.9 million jobs either through direct or indirect support ( O'Keefe, 2018 ). The top five milk producing states in the US are California, Wisconsin, Idaho, New York, and Texas, with California accounting for nearly 20% of national production ( Sumner and Matthews, 2019 ; USDA, 2020 ). The dairy industry is such a major part of California's economy that in 2019 the associated impact from milk production and processing was about $57.7 billion dollars, providing over 179,900 jobs ( Sumner and Matthews, 2019 ). Dairy is the leading agricultural commodity produced in California, accounting for nearly 13% of the $49.9 billion dollars in cash receipts generated for the top ranked agriculture producing state ( CDFA, 2019 ). Not only is the dairy industry a major driver of the economy but its products serve a substantial nutritional benefit to the growing human population.

Milk and dairy products are a well-known source of calcium, vitamins, and other selected minerals as well as being a complete high-quality protein. One of the most well-documented nutritional benefits of dairy products is for bone health—particularly for its ability to prevent osteoporosis and other bone diseases. In particular the calcium in milk positively affects bone mass in children and when coupled with vitamin D, as seen in fortified milk products, will prevent bone loss and osteoporotic fractures in aging populations ( Caroli et al., 2011 ). For low-income countries struggling with nutritional deficiencies in children, studies have shown that supplementation with dairy products causes a significant increase in vitamin B-12 plasma concentrations, improves cognition, growth and activity ( Allen, 2003 ; Siekmann et al., 2003 ). In addition, maternal milk intake during pregnancy is positively associated with infant birth weight, and subsequent bone mineral content during childhood ( Gil and Ortega, 2019 ). Other milk components, including bioactive peptides present in the whey components of milk were shown to benefit the immune system due to their antimicrobial and immunomodulatory properties ( Madureira et al., 2010 ). Consumption of dairy products has shown an inverse relationship with cardiovascular disease in that consumption of milk and dairy is associated with a lower incidence of type-2 diabetes and improvements in glucose homeostasis ( Hirahatake et al., 2014 ). While milk is relatively high in saturated fat it has been shown that milk intake did not increase cardiovascular risk ( Visioli and Strata, 2014 ). Furthermore, milk intake was associated with reduced risk of childhood obesity as well as improved body composition and weight loss in adults ( Thorning et al., 2016 ). Dairy intake was also shown to be inversely associated with incidence of cancer including colorectal, bladder, gastric, and breast cancer and was not shown to be associated with any other additional forms of cancer ( Thorning et al., 2016 ). Although dairy production serves many benefits to overall nutrition, human health, and the economy, there has been increasing concern about the impact of dairy on the environment.

Impact of Dairies on Climate Change and Air Quality

The earth's surface has undergone massive increases in temperature, primarily in the last three decades, and the last 30 years we have seen the warmest period ever recorded ( IPCC, 2014 ). In addition to this temperature increase, there have been other major changes to the climate including trends of increasing ocean temperature, rising sea level, as well as a major increase in greenhouse gas emissions ( IPCC, 2014 ). Another phenomenon that has occurred over the last few centuries is an increase in ocean uptake of CO 2 , causing ocean acidification and a decrease in surface water pH, as well as a rapid decrease in glaciers and ice sheets around the globe. These major changes in the climate are primarily due to anthropogenic (human caused) emissions of GHGs that have steadily increased since the beginning of the industrial revolution in the 1750s ( Place and Mitloehner, 2010 ). Atmospheric concentrations of CO 2 , CH 4 , and N 2 O are also the highest they have been in at least the last 800,000 years, with about 78% of these CO 2 emissions resulting from industrial processes and the combustion of fossil fuels ( IPCC, 2014 ). Several studies have indicated that the production of livestock, including the stages of growing, transport, processing, and consumption have a relatively large impact on climate change ( de Vries and de Boer, 2010 ; Milani et al., 2011 ). Dairy cattle in particular were shown to impact the environment through their potential negative contributions to air, water, and land ( Naranjo et al., 2020 ).

In regards to the environment, the US Dairy industry has seen substantial improvements over the years. In particular it has seen a great increase in milk production primarily due to dramatic increases in milk production per cow, increase in average cow numbers per farm, as well as an overall decrease in total animal numbers ( Wolf, 2003 ; Barkema et al., 2015 ). Some other major changes over the last 50 years include a shift to a primarily Holstein dairy herd (90%), an increased heifer growth rate, decreased age at first calving, and an increase in the use of artificial insemination ( Capper et al., 2009 ). Nutrition of dairy animals has also allowed for a substantial improvement in production via use of total mixed-rations balanced for nutrient and energy requirements accounting for each animals age and stage of lactation ( National Research Council, 2001 ). Genetic selection has also been a major driver in increased productivity, longevity, and efficiency of dairy cows, further reducing the environmental impact per unit of milk production ( Pryce and Haile-Mariam, 2020 ). These improvements in nutrition and genetics, in conjunction with improvements to herd management, accomplished primarily through increasing density on dairy farms, have resulted in a fourfold increase in milk yield from the mid-1940s until 2007 ( Von Keyserlingk et al., 2013 ). This efficiency of milk production has continued to improve to 2014 where 1 kg of energy and protein corrected milk (ECM) for California emitted between 1.12 and 1.16 kg of CO 2 equivalents (CO 2 e) in 2014 compared with 2.11 kg of CO 2 e in 1964, resulting in a 45% reduction in CO 2 e ( Naranjo et al., 2020 ). The dairy industry has continued to still further these improvements. Dairy production systems in 2017 compared with 2007 have reduced their inputs by 25.2% for animal numbers, 17.3% for total feed, 20.8% for land, and 30.5% for water of one million metric ton of energy-corrected milk, furthering the exceptional productivity gains and environmental progress of the industry ( Capper and Cady, 2020 ). Even with these major advancements made over the last century, dairy systems still impact the environment through: GHG emissions from enteric fermentation, manure management, and feed production, water use for feed production and milk processing, water quality with contaminants including nitrogen (N) and phosphorous (P) from manure, as well as the requirement for land used in feed production ( Naranjo et al., 2020 ). In addition to the direct impacts of cattle, such as N and P as a result of dairy production systems, there are also environmental impacts associated with dairy processing and subsequent production ( Milani et al., 2011 ).

Manure Emissions From Dairy Cattle

Dairy manure has the potential to negatively impact the environment. Nitrogen not retained by the animal or secreted in milk will be excreted in the urine and feces of the animal ( Hristov et al., 2019 ). Urine is more susceptible to losses of N to the environment from the animal waste as compared with fecal N ( Dijkstra et al., 2013 , 2018a ). Dairy waste is a significant source of N and P that when land applied in excess of crop requirements can cause contamination of surface water ( Knowlton and Cobb, 2006 ). This excess N and P in water causes a rapid bloom in the growth of algal populations that consume dissolved oxygen in water, termed eutrophication, which reduces the available dissolved oxygen required for growth of aquatic animal life ( Knowlton and Cobb, 2006 ). Excess N can also contaminate ground water through leaching. This poses a problem for human and animal health as consumed nitrate from drinking water is converted to nitrite in the digestive tract, which replaces oxygen in hemoglobin and leads to cyanosis (oxygen starvation) ( Knowlton and Cobb, 2006 ).

Air quality also affects human and animal health as well as the environment, and dairy cattle have been known to contribute to poor air quality. One such compound that affects air quality produced by dairy cattle is NH 3 . Ammonia is produced when N in urea from the animal's urine reacts with urease present in feces ( Place and Mitloehner, 2010 ). Ammonia production from dairy waste is dependent on a variety of factors including: urea content in urine, pH, and temperature, as well as the enzymatic activity of urease ( Muck, 1982 ; Sun et al., 2008 ). In addition to NH 3 losses from fresh waste, volatilization can occur during waste application to soil as a fertilizer, as well as during the long term housing and storage of manure ( Bussink and Oenema, 1998 ). Total losses of NH 3 can be between 0.82 and 250 g NH 3 /cow/day, with the total loss dependent on the amount and composition of animal waste as well as the environment and management conditions of the manure storage ( Bussink and Oenema, 1998 ; Hristov et al., 2011 ). Dairy waste management strategies greatly influence air emissions of NH 3 . The greatest NH 3 emissions occur after field application, followed by the manure management strategies, for example, separated liquid and solids, aerated, straw covered, untreated, then anaerobic digested ( Amon et al., 2006 ).

Nitrogen in waste can also contribute to GHG production through the formation and volatilization of nitrous oxide (N 2 O). Nitrous oxide is created during incomplete microbial denitrification process where nitrate is converted to N gas with the potential to create N 2 O, an extremely volatile byproduct ( Place and Mitloehner, 2010 ). Land applied dairy manure on cropland as well as the long term storage of manure in lagoons can contribute to emissions of N 2 O ( Velthof et al., 1998 ; Place and Mitloehner, 2010 ). The N 2 O emissions during storage depend on the N and carbon content of the manure ( Amon et al., 2006 ). Nitrous oxide production and subsequent volatilization is also dependent on environment and management. Higher temperatures as well as surface coverings contribute to increasing emissions, whereas anaerobic conditions, such as those found in lagoon systems, have lower N 2 O emissions ( Dustan, 2002 ). The process of long term storage of manure seems to also contribute a larger proportion of N 2 O emissions compared with land application with aerated, straw covered, digested, separated, and untreated manure contributing decreasing amounts of N 2 O emissions ( Amon et al., 2006 ).

Another substantial GHG produced by dairy cattle waste is methane (CH 4 ). The amount of CH 4 emitted by dairy waste is dependent on the amount of carbon, hydrogen, and oxygen present in the waste, making manure storage, diet, and bedding major contributors to total CH 4 production ( Place and Mitloehner, 2010 ). A smaller proportion of CH 4 is also produced in the hindgut of the animal via post ruminal digestion and fermentation ( Ellis et al., 2008 ). This CH 4 is mostly absorbed from the hindgut (89%) and eventually eructated by the animal or excreted with the manure (11%) ( Murray et al., 1976 ; Immig, 1996 ; de la Fuente et al., 2019 ). Manure CH 4 emissions are substantially higher from long term storage compared with field application ( Amon et al., 2006 ). These emissions are highest from straw covered manure and emissions decrease with untreated manure, followed by separation, aeration, and digested manure management methods ( Amon et al., 2006 ).

Dairy waste can also produce volatile organic compounds (VOC). Volatile organic compounds are a class of chemicals that when reacted with oxides of N and sunlight contribute to ozone formation ( Place and Mitloehner, 2010 ). There were 73 detectable VOCs from slurry wastewater lagoons with the most common VOCs being methanol, acetone, propanal, and dimethylsulfide ( Filipy et al., 2006 ; Shaw et al., 2007 ). As with other waste emissions, VOCs from dairy waste increase with ambient air temperature with summer months having the highest rates of VOC emissions ( Filipy et al., 2006 ). The largest contribution of VOCs on dairy systems come from fermented feedstuffs (i.e., silage) ( Place and Mitloehner, 2010 ).

Effect of Nutrition on Emissions From Dairy Cattle

Dairy cattle enteric emissions have been shown to contain a variety of gases. For example dairy cattle emit CO 2 as a byproduct of aerobic cellular respiration, which is the GHG with the greatest contribution to climate change ( Place and Mitloehner, 2010 ). However, this gas is not considered a net contributor to the rise in GHGs due to the CO 2 having been previously recycled from the atmosphere by fixation during photosynthesis in plants, which are then consumed by the cattle ( Steinfeld et al., 2006 ). Dairy cattle can also produce N 2 O from enteric emissions as a result of the NO 3 reduction process that takes place by the microbes in the rumen ( Kaspar and Tiedje, 1981 ). Due to the small production of enteric N 2 O, these emissions are not always considered in dairy emission analyses ( Casey and Holden, 2005 ).

The most significant enteric emission compound from dairy cattle is CH 4 . Methane acts as a hydrogen sink in the rumen and is an end product of CO 2 reduction by methanogenic archaea ( Janssen and Kirs, 2008 ). Methanogens serve an important role in rumen health by removing this hydrogen that can be toxic to some bacterial communities and also causes the disease state rumen acidosis ( Beauchemin et al., 2009 ). In addition to being a potent GHG, CH 4 also accounts for a 2–12% loss of potential energy available to the animal that could otherwise be used for maintenance and productive purposes as growth gestation, or lactation ( Moe and Tyrrell, 1979 ).

Dairy cattle diets have a significant impact on enteric emissions, mostly CH 4 . As there is large variability in the ingredient and chemical composition of diets fed to dairy cattle, nutrition and feeding strategies have the greatest potential for reducing CH 4 emissions, with potential reported reductions between 2.5 and 15% ( Knapp et al., 2014 ). The amount of CH 4 produced is dependent on many factors including intake and chemical composition of the carbohydrate, retention time of feed in the rumen, rate of fermentation of different feedstuffs, as well as the rate of methanogenesis ( Beauchemin et al., 2009 ). Altering feed digestibility and chemical composition cause a shift in the proportions of volatile fatty acids (VFA) with the predominant VFAs being propionate, butyrate, and acetate ( Knapp et al., 2014 ). This shift in VFA proportion is important because propionate also acts as a hydrogen sink so shifting from acetate and butyrate formation to propionate will consume reducing equivalents and help preserve the pH balance in the rumen ( Hungate, 2013 ). An overall reduction in CH 4 emissions or a shift in VFAs can be accomplished through a variety of altered feeding strategies. More energy dense or more digestible feedstuffs result in additional energy available to the animal and generate less CH 4 from fermentation ( Knapp et al., 2014 ). An increase in starch proportion of the diet, such as through an increase in concentrate levels, also results in a more rapid fermentation of these feedstuffs and therefore decreased CH 4 production ( Moe and Tyrrell, 1979 ; Johnson and Johnson, 1995 ). Feeding higher starch diets requires increased grain production, which can cause additional consumption of fossil fuel and fertilizers that results in an increase in N 2 O and CO 2 ; however, this system is usually offset by the substantial decrease in overall in CH 4 emissions ( Johnson et al., 2002 ; Lovett et al., 2006 ). Feeding of cereal forages can also favor propionate production and reduce CH 4 emissions due to the higher starch concentration ( Beauchemin et al., 2009 ). Higher concentrations of legumes, such as alfalfa, when compared with grass forage based diets can also lead to an overall decrease in CH 4 emissions ( McCaughey et al., 1999 ). Age of harvest of forage also has a significant impact on emissions, with advancing maturity resulting in more lignified and less fermentable substrate contributing to increasing emissions associated with higher ruminal acetate ( Pinares-Patiño et al., 2003 ). In addition to alterations in forage or concentrate composition and ratio, supplementation of lipids to dairy cattle diets can also mitigate enteric emissions ( Hristov et al., 2013b ). Replacing concentrates with lipids results in a decrease in fermentable substrate by the microbes in the rumen and can also decrease total protozoa and methanogen populations ( Ivan et al., 2004 ). An inclusion of high-oil by-products, such as distillers grains or oilseed meals, can result in decreased CH 4 emissions ( Hristov et al., 2013b ). Research on ensiled feeds in relation to enteric emissions is generally lacking, although it is anticipated that corn silage will mitigate emissions due to its higher starch content ( Gerber et al., 2013 ). Furthermore, when directly comparing grass-versus corn silage, a higher inclusion of corn silage seems to mitigate enteric CH 4 emissions ( Mills et al., 2008 ; Doreau et al., 2012 ). There are many potential methods to mitigate enteric emissions through alterations to nutrition strategy and composition.

Manure emissions are also significantly impacted by various dairy cattle feeding strategies. One of the main issues with altering feeding strategies to reduce enteric emissions is that fermentable substrate in the manure can increase, as has been seen with increasing the concentrate to forage ratio in the diet ( Hindrichsen et al., 2006 ; Beauchemin et al., 2009 ). This response has also been seen with the supplementation of certain fatty acids ( Kreuzer and Hindrichsen, 2006 ). To alleviate this issue, feeding concentrate with higher lignified fiber has been shown to mitigate both enteric and manure-derived emissions ( Kreuzer and Hindrichsen, 2006 ; Aguerre et al., 2012 ). These changes to concentrate ratio do not have an impact on N containing manure emissions, as would be expected ( Hindrichsen et al., 2006 ; Aguerre et al., 2012 ). The greatest impact of diet on waste emissions can be seen when feeding low crude protein (CP) diets to dairy animals, which results in decreased excreted N and subsequent NH 3 volatilization ( Cardenas et al., 2007 ; Lee et al., 2012 ; Edouard et al., 2019 ). Comparing fresh grass with prepared hay at the same CP content, feeding hay causes a higher overall N and C/N ratio excreted but waste from grass fed animals tends to volatilize more NH 3 emissions ( Külling et al., 2003 ). Corn silage inclusion in diets has also caused changes to manure emission profiles. For example when comparing corn silage versus grass silage, corn silage tended to reduce urinary N excretion ( Mills et al., 2008 ). When adding corn silage to alfalfa silage based diets there is also an improvement in N efficiency leading to a decrease in N losses in urine and subsequent decreases in available NH 3 and N 2 O volatilization ( Gerber et al., 2013 ). Higher sugar forages also reduce N excretions, which also have the potential to limit the N available to be volatilized as gaseous emissions ( Miller et al., 2001 ; Parsons et al., 2012 ; Gerber et al., 2013 ). Overall a variety of feeding strategies can be employed to help mitigate emissions from enteric and waste sources of dairy animals.

Mitigation Strategies for Dairy Cow Enteric Gas Emissions

In addition to changes to the diet ingredient composition, there are also additives to diets that may mitigate enteric emissions. While there are various types of strategies to alter enteric sourced emissions this section will focus primarily on methods to alter CH 4 . One promising strategies for CH 4 reduction is via feed supplementation of the methanogenic inhibitor, 3-Nitrooxypropanol (3-NOP). 3-Nitrooxypropanol is a structural analog to methyl-coenzyme M, which acts on methyl-coenzyme M reductase (MCR), a nickel enzyme involved in the final reduction stages of methanogenesis ( Duin et al., 2016 ). In the rumen system 3-NOP was shown to mimic methyl-coenzyme M and target the active site of MCR, thus inhibiting the enzymes activity and subsequently causing a decrease in CH 4 production ( Duin et al., 2016 ). Research demonstrated that feeding 3-NOP to cattle decreased enteric CH 4 emissions up to 95% in vitro ( Martínez-Fernández et al., 2014 ) and 84% in vivo ( Vyas et al., 2016 ). 3-NOP was tested in vivo in multiple ruminant models including sheep ( Martínez-Fernández et al., 2014 ), beef cattle ( Romero-Perez et al., 2015 ; Vyas et al., 2016 ), as well as Holstein dairy cattle ( Reynolds et al., 2014 ; Hristov et al., 2015 ; Lopes et al., 2016 ; Haisan et al., 2017 ). Reynolds et al. (2014) fed 3-NOP at a rate of either 500 or 2,500 mg/d via rumen fistula before each feeding and using respiration calorimetry found a reduction of 6.6 and 9.8% in CH 4 emissions, respectively. They also found a decrease in dry matter intake (DMI) and an increase in milk protein at the higher dose, without other changes in production parameters. Haisan et al. (2017) also fed 2,500 mg/d and using the SF6 systems measured a reduction in emissions from 17.8 to 7.18 g/kg of DMI without adverse effects to milk or DMI. Hristov et al., 2015 fed 3-NOP at a rate of 40, 60, or 80 mg/kg of DMI and measured reductions via a GreenFeed system of 25, 31, and 32%, respectively. They also found no changes to DMI or milk production with an increase in protein yield following supplementation. Similarly, Lopes et al. (2016) also fed 60 mg/kg of DMI and found a 31% decrease in emissions with an increase in milk fat concentration. Dijkstra et al. (2018b) evaluated the overall efficacy of 3-NOP in research trials and determined that greater 3-NOP dose results in a greater reduction of CH 4 emissions. These trials also used different diets, which did not seem to effect the impact of 3-NOP on emissions. However, this molecule has yet to be evaluated for its efficacy among different dairy breeds and the potential side effects of its use have not fully elucidated. Additionally, it has yet to be determined whether 3-NOP has any unintended consequences of carryover to the excreta of supplemented animals.

Nitrates offer great promise for their potential to mitigate CH 4 and have been well studied for their use in beef cattle diets with more recent literature focusing on the potential for use in dairy cattle. Nitrate in the diet serves as a non-protein N source that acts as an electron receptor resulting in effective and consistent reduction of enteric emissions. However, nitrate has the potential to induce methemoglobinaemia and is a known carcinogen ( Lee and Beauchemin, 2014 ). Nitrate toxicity can generally be avoided when the rumen ecosystem is allowed time to adapt ( Hristov et al., 2013b ). Even with the potential for toxicity, the benefits of 16–50% reduction in CH 4 emissions continue to drive research feeding nitrates ( Leng and Preston, 2010 ). Van Zijderveld et al. fed nitrate at a rate of 21 g/kg DMI and measured a persistent reduction in CH 4 of 16% via use of open-circuit indirect calorimetry chambers ( Van Zijderveld et al., 2011 ). They did not measure changes in milk yield or DMI for the supplemented animals. Similar research conducted by other authors found a reduction in emissions of CH 4 /d from 363 g for control animals to 263 g for nitrate supplemented animals also at 21 g/kg DMI ( Klop et al., 2016 ). They also measured a reduction in milk protein concentration as well as DMI for nitrate-supplemented cows. When high levels of nitrate (20 g/ kg DMI) were supplemented in a similar study design they found a 31% reduction in CH 4 along with a decrease in DMI during nitrate feeding ( Lund et al., 2014 ). Another study found a 28% decrease in methanogenesis after feeding nitrate at 2.3% of DM to nonlactating cows, however they also found a significant decrease in feed intake from the supplemented animals ( Guyader et al., 2015 ). Another trial reported a 10% decrease in DMI, coupled with a 17% decrease in CH 4 where dairy cattle diets were supplemented with nitrate at 1.5% of DMI ( Meller et al., 2019 ). A meta-analysis found a persistent reduction in CH 4 emissions in both in vitro and in vivo studies ( Lee and Beauchemin, 2014 ). Similar to 3-NOP, TMR composition did not seem to have a major effect on nitrate supplementation as these studies all saw a significant decrease in emissions with vastly different diets.

Plant biological compounds have also been explored for their potential to reduce emissions. Condensed tannins are secondary phenolic compounds that generally discourage consumption by herbivories and also concentrate N in the plant ( Waghorn, 2008 ). When consumed by dairy cattle these tannins bind protein in the rumen, which reduces the degradation of protein and enhances protein flow to the intestines ( Beauchemin et al., 2009 ). Tannin source appeared to make a major difference in subsequent mitigation of CH 4 emissions from dairy cattle. For example, the Hedysarum coronarium species supplemented at 27 g /kg DMI resulted in lower CH 4 emissions by dairy cattle ( Woodward et al., 2002 ). Whereas, Schinopsis quebracho-colorado supplemented at 0, 1, or 2% of dietary DM did not have any effect on enteric emissions or dry matter intake of beef cattle ( Beauchemin et al., 2007 ). Additional studies looking at Lotus pedunculatus (fed at 10% of dry matter) and Medicago sativa (fed at 0.1% of dry matter) tannin supplementation found decreased CH 4 emissions from both strains of condensed tannins, although DMI was not measured, which were attributed to reducing hydrogen production and direct inhibition on methanogenic archaea ( Tavendale et al., 2005 ). A meta-analysis identified a general anti-methanogenic effect of tannins across different sources and that the variation in methane reduction seen in previous studies may have been due to the low tannin levels used in those trials ( Jayanegara et al., 2012 ). They also found that dietary tannins tended to increase DMI but decrease total tract digestibility, apparent CP digestibility, and neutral detergent fiber digestibility. As with previous feed supplementation, these trials did not quantify emission changes to waste sources. Additional research into tannins in various diets as well as its effect on milk production and manure CH 4 emissions needs to be explored.

In addition to tannins, secondary plant compounds called essential oils have been explored for their antimicrobial properties. Essential oils are naturally occurring volatile components in plants that provide the plant specific color and flavor characteristics ( Benchaar et al., 2008 ). Essential oils reduced CH 4 production through inhibiting growth and energy metabolism of selected bacteria and archaea including methanogens ( Benchaar et al., 2008 ). Over 250 essential oils have been identified and contain mixtures of terpenoids, a variety of low molecular weight aliphatic hydrocarbons, alcohols, acids, aldehydes, acrylic esters, N, sulfur, coumarins, and homologs of phenylpropanoids ( Beauchemin et al., 2009 ). These essential oils underwent in vitro screening for their potential to reduce rumen CH 4 emissions and while 35 were found to be effective only six were found to have significant decreases in emissions without disrupting digestibility ( Bodas et al., 2008 ). It is difficult to directly compare essential oils because of the number of different compounds as well as the difference in study design and species studied. In addition, few essential oils have been thoroughly evaluated in vivo . Benchaar and Greathead (2011) performed additional in vitro testing and found decreased CH 4 production following supplementation with oregano, rhubarb, thyme, cinnamon, horse radish, frangula, and garlic. Tekippe et al. (2011) fed oregano leaf at a rate of 500 g/d to lactating dairy cattle and measured rumen CH 4 production 8 h after feeding. They found a decrease in total CH 4 yield but did not see adverse effects on DMI or milk yield with the added benefit of increased milk fat content. In a follow up study by Hristov et al. (2013a) they fed lactating dairy cows 250, 500, and 750 g of oregano leaf per day and found a linear reduction in methane per unit of DMI coupled with a linear decrease in DMI but no differences in any milk production parameters. In addition to particular isolates of essential oils, there are also commercial essential oil blends being marketed for their potential to reduce enteric CH 4 . One essential oil blend is Agolin SA created in Bière, Switzerland that is comprised of coriander oil, geranyl acetate, and eugenol. Agolin was tested in vitro and found a significant initial decrease in rumen CH 4 , but the effect did not persist over time ( Klop et al., 2017b ). Another Agolin in vitro trial found similar results where there was an initial reduction in methane, but the effect was not constant over the total 72 h incubation period ( Castro-Montoya et al., 2015 ). These authors also conducted feeding trials with the Agolin essential oil product. Castro-Montoya et al. (2015) found a trend in reduction of daily emissions relative to intake and ( Klop et al., 2017a ) found initial decrease in CH 4 /DMI only for the first 2 weeks of feeding Agolin, after which Agolin did not impact CH 4 . In addition, Klop et al. (2017a) reported a decrease in DMI over the second half of the supplementation period. Hart et al. (2019) also supplemented lactating dairy cattle with Agolin essential oils and measured a reduction in CH 4 emissions per pen. Changes to DMI, milk production, or fat composition after feeding of essential oils have also been reported following Agolin supplementation. For example, Santos et al., 2010 reported numerically lower DMI with an increase in milk fat production, a 0.03 kg/day increase in fat production, from Agolin supplemented cows, whereas Elcoso et al. (2019) saw an increase in ECM supplemented animals without differences in DMI. However, for Santos et al. (2010) the Agolin treatment was applied to the pen and not the individual animal. Elcoso et al. (2019) also estimated rumen CH 4 production from fermented rumen fluid and found supplemented animals to be lower, but there was an interaction between the time and treatment. Hart et al. (2019) also found a greater milk yield and ECM for Agolin supplemented animals. Clearly the large discrepancy in responses across research studies for Agolin emphasizes the need for additional research to determine if the essential oil product has application at the farm level to reduce enteric CH 4 emissions.

Mitigation Strategies for Dairy Cow Manure Gas Emissions

While there are many ways in which to alter manure emissions depending on the desired outcome this literature search will focus on methods to alter CH 4 emissions specifically, of which there are quite a few promising strategies. One manure amendment strategy includes the use of biochar. Biochar is a general term applied to products produced by thermal decomposition from a variety of biomass substrates for agricultural applications including the added benefit of optimizing the process of composting ( Godlewska et al., 2017 ). Biochar was shown to have a multitude of benefits including improving the overall process of composting, improving N conservation, facilitating nutrient transformation, and favoring oxygen supply ( Vandecasteele et al., 2016 ; Chen et al., 2018 ; Mao et al., 2018 ). Other studies demonstrated that biochar improved soil physicochemical properties, benefited nutrient conservation as well as boosted crop production ( Li et al., 2015 ; Mao et al., 2017 ; Wu et al., 2017 ). While the benefits of biochar as amendments to poultry and pig manure have been well-documented ( Agyarko-Mintah et al., 2017 ; Chen et al., 2017 ; He et al., 2019 ), its use in dairy cattle manure management has been less thoroughly studied. Jindo et al. (2012) added biochar to cattle manure to measure microbial communities, causing a significant increase in the C/N ratio from the additional of high carbon biochar materials, but they did not measure emissions from these systems. Duan et al. (2019) applied wood or wheat straw biochar with and without bacterial supplementation to cattle manure compost. While this study did not measure CH 4 emissions specifically, they found that biochar in addition to bacterial amendments enhanced the compost overall and that Bacteroidales, Flavobacteriales , and Bacilli were the communities with the highest abundance in the samples. Awasthi et al. (2020) also tested biochar with and without a bacterial inoculum applied to fresh cattle manure in a reactor and found treatments with the inclusion of biochar produced substantially less CH 4 as compared with the control. Overall, the impact and mechanism of action of biochar on CH 4 emissions from dairy waste specifically deserves further study.

Bacterial inoculums, as well as the supplementation of bacterial produced enzymes, have been well-researched in the literature for their potential to alter CH 4 emissions. Bacteria are involved in many of the breakdown processes that occur in manure management systems including reactions of hydrolysis, acidogenesis, acetogenesis, and methanogenesis, the latter of which has the potential to increase methane production ( Juodeikiene et al., 2017 ). While increased CH 4 may seem in conflict with the present literature review, this manure management strategy can be applied to systems where CH 4 can be captured and transformed into biofuel or other renewable resources. One such example is through anaerobic digestion in which organic material is degraded by microbes in the absence of oxygen ( Rodriguez Chiang, 2011 ). A variety of bacterial communities have been researched for their potential to change CH 4 emissions from various substrates. Juodeikiene et al. studied Lactobacillus delbrüeckii , and found an increase in methane of 76% from dairy wastewater from milk processing, as compared with 38% without the addition of bacteria ( Juodeikiene et al., 2017 ). Xu et al. pretreated corn straw with Bacillus subtilis , and increased CH 4 production 17.35% above the untreated control ( Xu et al., 2018 ). He et al. also supplemented microalgal biomass with Bacillus licheniformis , and bacterial supplementation increased CH 4 production from 9.2 to 22.7% ( He et al., 2016 ). Commercial products have also been marketed for their application in manure management systems, including BiOWiSH products. BiOWiSH products contain a proprietary mixture of Bacillus and Lactobacillus , including Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus pumilus, Pediococcus acidilactici, Pediococcus pentosaceus, Lactobacillus plantarum, Bacillus meagerium, Bacillus coagulans , and Paenibacillus polymyxia , a product covered by a patent outlined by Carpenter et al. (2014) . The process to create BiOWiSH involves individually fermenting each organism, followed by harvesting and then drying of each organism. Finally, the dried organism ground to produce a powder with a final moisture content <5% and a final bacterial concentration between 10 5 and 10 11 colony forming units (CFU) per gram of dried product. While these products have not been evaluated for their effect on CH 4 specifically, these products claim to digest sludge, and reduce biological oxygen demand, total suspended solids, total Kjeldahl N, and odor from manure lagoons. The BiOWiSH product has been applied to dairy waste systems and showed promise for manure mitigation including: a reduction in total suspended solids and a degradation and removal of N ( Lee, 2012 ; Pal, 2012 ; Holland, 2017 ). However, BiOWiSH has not been studied with respect to its effects on CH 4 emissions from dairy wastewater systems.

Gypsum based products have been applied to dairy waste systems for manure amendments. One of the more common forms of gypsum used for manure amendment is flue gas desulphurization gypsum that is a by-product of wet gas desulphurization from coal-fired power stations ( Febrisiantosa et al., 2018 ). This gypsum has a low heavy metal content and contains high concentrations of S, Si, and Ca that are essential minerals nutrients required by plants ( Guo et al., 2016 ). Gypsum has been fairly well-characterized for its effects on N containing compounds. Tubail et al. found gypsum supplemented dairy manure lost significantly less N as compared with the control dairy manure without supplementation ( Tubail et al., 2008 ). Li et al. applied gypsum to pig manure compost and found significant reductions in NH 3 and enhanced mineral and total N contents ( Li et al., 2018 ). Hao et al. applied gypsum to beef cattle manure and found a significant reduction in CH 4 emissions from the medium and high doses of gypsum as compared with the control ( Hao et al., 2005 ). Yang et al. studied kitchen waste compost and found the addition of gypsum to dramatically reduce CH 4 emissions by 85.8% ( Yang et al., 2015 ). While these study designs don't quite have the same application as is intended in this literature review, the potential for use of gypsum as a manure amendment is promising. There are also commercial additives being marketed for their potential to mitigate CH 4 emissions, including SOP Srl, a company that makes the SOP Lagoon products. SOP Lagoon consists of calcium sulfate dihydrate (agricultural gypsum) that is processed with the company's proprietary technology. The product's claim is to improve liquid manure management through inhibiting the production and release of GHGs (e.g., CH 4 and N 2 O) and criteria pollutants (e.g., NH 3 ) while also reducing the odor intensity from liquid manure. Borgonovo et al. first tested the gypsum-based commercial additive, “SOP LAGOON,” on fresh dairy manure and found the additive to be effective in reducing direct NH 3 and GHG emissions, including a significant mitigation of CH 4 emissions ( Borgonovo et al., 2019 ). Recent literature by Peterson et al. applied SOP Lagoon to liquid stored dairy cattle manure over a 2 week period and found similar results including significant reductions in NH 3 emissions (22.7% for the supplemented systems as compared with an unsupplemented control) ( Peterson et al., 2020 ). With the strong literature documenting the potential for gypsum to decrease CH 4 emissions, this seems like a viable manure amendment strategy.

In addition to the previously described additives, a variety of additional organic substrates have been applied as amendments in diverse applications. These additional amendments include lime and coal fly ash ( Fang et al., 1999 ; Wong et al., 2009 ), zeolite ( Awasthi et al., 2016 ; Chan et al., 2016 ), bentonite ( Wang et al., 2016 ), clay ( Chen et al., 2018 ), and medical stone ( Awasthi et al., 2017 ; Wang et al., 2017 ), among others. These amendments require further research to evaluate their potential use in dairy manure specifically as well as the resulting CH 4 emissions after their application.

Conclusions

There is an increasing amount of literature and research data concerning strategies to further reduce livestock's impact on the environment. However, there is no one method of environmental sustainability in these systems and even still there are many unanswered questions. Future research needs to better quantify full reduction potential and elucidate the mechanism of actions of these compounds including 3-NOP, tannins, essential oils, bacterial inoculums, and biochar, among others. Furthermore, slight alterations to dairy cattle diets can cause major changes in both enteric and waste emissions. Research on mitigating the environmental impact of dairy cattle will allow dairy producers to contribute to a more sustainable dairy production system.

Data Availability Statement

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding authors.

Author Contributions

CP wrote the manuscript draft. All authors contributed to the article and approved the submitted version.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Aguerre, M., Wattiaux, M., and Powell, J. (2012). Emissions of ammonia, nitrous oxide, methane, and carbon dioxide during storage of dairy cow manure as affected by dietary forage-to-concentrate ratio and crust formation. J. Dairy Sci. 95, 7409–7416. doi: 10.3168/jds.2012-5340

PubMed Abstract | CrossRef Full Text | Google Scholar

Agyarko-Mintah, E., Cowie, A., Singh, B. P., Joseph, S., Van Zwieten, L., Cowie, A., et al. (2017). Biochar increases nitrogen retention and lowers greenhouse gas emissions when added to composting poultry litter. Waste Manage. 61, 138–149. doi: 10.1016/j.wasman.2016.11.027

Allen, L. H. (2003). Interventions for micronutrient deficiency control in developing countries: past, present and future. J. Nutrition 133, 3875S–3878S. doi: 10.1093/jn/133.11.3875S

Amon, B., Kryvoruchko, V., Amon, T., and Zechmeister-Boltenstern, S. (2006). Methane, nitrous oxide and ammonia emissions during storage and after application of dairy cattle slurry and influence of slurry treatment. Agric. Ecosyst. Environ. 112, 153–162. doi: 10.1016/j.agee.2005.08.030

CrossRef Full Text | Google Scholar

Awasthi, M. K., Duan, Y., Awasthi, S. K., Liu, T., and Zhang, Z. (2020). Effect of biochar and bacterial inoculum additions on cow dung composting. Bioresour. Technol. 297:122407. doi: 10.1016/j.biortech.2019.122407

Awasthi, M. K., Pandey, A. K., Bundela, P. S., Wong, J. W., Li, R., and Zhang, Z. (2016). Co-composting of gelatin industry sludge combined with organic fraction of municipal solid waste and poultry waste employing zeolite mixed with enriched nitrifying bacterial consortium. Bioresour. Technol. 213, 181–189. doi: 10.1016/j.biortech.2016.02.026

Awasthi, M. K., Wang, M., Chen, H., Wang, Q., Zhao, J., Ren, X., et al. (2017). Heterogeneity of biochar amendment to improve the carbon and nitrogen sequestration through reduce the greenhouse gases emissions during sewage sludge composting. Bioresour. Technol. 224, 428–438. doi: 10.1016/j.biortech.2016.11.014

Barkema, H. W., von Keyserlingk, M. A., Kastelic, J. P., Lam, T., Luby, C., Roy, J.-P., et al. (2015). Invited review: changes in the dairy industry affecting dairy cattle health and welfare. J. Dairy Sci. 98, 7426–7445. doi: 10.3168/jds.2015-9377

Beauchemin, K., McGinn, S., Martinez, T., and McAllister, T. (2007). Use of condensed tannin extract from quebracho trees to reduce methane emissions from cattle. J. Anim. Sci. 85, 1990–1996. doi: 10.2527/jas.2006-686

Beauchemin, K. A., McAllister, T. A., and McGinn, S. M. (2009). Dietary mitigation of enteric methane from cattle. CAB Rev. 4, 1–18. doi: 10.1079/PAVSNNR20094035

Benchaar, C., Calsamiglia, S., Chaves, A., Fraser, G., Colombatto, D., McAllister, T., et al. (2008). A review of plant-derived essential oils in ruminant nutrition and production. Anim. Feed Sci. Technol. 145, 209–228. doi: 10.1016/j.anifeedsci.2007.04.014

Benchaar, C., and Greathead, H. (2011). Essential oils and opportunities to mitigate enteric methane emissions from ruminants. Anim. Feed Sci. Technol. 166, 338–355. doi: 10.1016/j.anifeedsci.2011.04.024

Bodas, R., López, S., Fernandez, M., García-González, R., Rodríguez, A., Wallace, R., et al. (2008). In vitro screening of the potential of numerous plant species as antimethanogenic feed additives for ruminants. Anim. Feed Sci. Technol. 145, 245–258. doi: 10.1016/j.anifeedsci.2007.04.015

Borgonovo, F., Conti, C., Lovarelli, D., Ferrante, V., and Guarino, M. (2019). Improving the sustainability of dairy slurry by a commercial additive treatment. Sustainability 11:4998. doi: 10.3390/su11184998

Bussink, D., and Oenema, O. (1998). Ammonia volatilization from dairy farming systems in temperate areas: a review. Nutr. Cycling Agroecosyst. 51, 19–33. doi: 10.1023/A:1009747109538

Capper, J. L., and Cady, R. A. (2020). The effects of improved performance in the US dairy cattle industry on environmental impacts between 2007 and 2017. J. Animal Sci. 98:skz291. doi: 10.1093/jas/skz291

Capper, J. L., Cady, R. A., and Bauman, D. E. (2009). The environmental impact of dairy production: 1944 compared with 2007. J. Anim. Sci. 87, 2160–2167. doi: 10.2527/jas.2009-1781

Cardenas, L. M., Chadwick, D., Scholefield, D., Fychan, R., Marley, C. L., Jones, R., et al. (2007). The effect of diet manipulation on nitrous oxide and methane emissions from manure application to incubated grassland soils. Atmos. Environ. 41, 7096–7107. doi: 10.1016/j.atmosenv.2007.04.055

Caroli, A., Poli, A., Ricotta, D., Banfi, G., and Cocchi, D. (2011). Invited review: dairy intake and bone health: a viewpoint from the state of the art. J. Dairy Sci. 94, 5249–5262. doi: 10.3168/jds.2011-4578

Carpenter, R., Showell, M. S., Barnes, J., and Pal, N. (2014). Microbial-Based Waste Water Treatment Compositions and Methods of Use Thereof . Google Patents.

Google Scholar

Casey, J., and Holden, N. (2005). Analysis of greenhouse gas emissions from the average Irish milk production system. Agric. Syst. 86, 97–114. doi: 10.1016/j.agsy.2004.09.006

Castro-Montoya, J., Peiren, N., Cone, J. W., Zweifel, B. V., and Fievez De Campeneere, S. (2015). In vivo and in vitro effects of a blend of essential oils on rumen methane mitigation. Livest. Sci. 180:134–142. doi: 10.1016/j.livsci.2015.08.010

CDFA (2019). 2018-2019 California Agricultural Statistics Review . California Department of Food and Agriculture.

Chan, M. T., Selvam, A., and Wong, J. W. (2016). Reducing nitrogen loss and salinity during ‘struvite' food waste composting by zeolite amendment. Bioresour. Technol. 200, 838–844. doi: 10.1016/j.biortech.2015.10.093

Chen, H., Awasthi, M. K., Liu, T., Zhao, J., Ren, X., Wang, M., et al. (2018). Influence of clay as additive on greenhouse gases emission and maturity evaluation during chicken manure composting. Bioresour. Technol. 266, 82–88. doi: 10.1016/j.biortech.2018.06.073

Chen, W., Liao, X., Wu, Y., Liang, J. B., Mi, J., Huang, J., et al. (2017). Effects of different types of biochar on methane and ammonia mitigation during layer manure composting. Waste Manage. 61, 506–515. doi: 10.1016/j.wasman.2017.01.014

Davis, C. G., and Hahn, W. (2016). Assessing the Status of the Global Dairy Trade . New York, NY: The International Food and Agribusiness Management Review.

de la Fuente, G., Yañez-Ruiz, D. R., Seradj, A. R., Balcells, J., and Belanche, A. (2019). Methanogenesis in animals with foregut and hindgut fermentation: a review. Animal Produc. Sci. 59, 2109–2122. doi: 10.1071/AN17701

de Vries, M., and de Boer, I. J. (2010). Comparing environmental impacts for livestock products: a review of life cycle assessments. Livest. Sci. 128, 1–11. doi: 10.1016/j.livsci.2009.11.007

Dijkstra, J., Bannink, A., Bosma, P. M., Lantinga, E. A., and Reijs, J. W. (2018a). Modeling the effect of nutritional strategies for dairy cows on the composition of excreta nitrogen. Front. Sustain. Food Syst. 2:63. doi: 10.3389/fsufs.2018.00063

Dijkstra, J., Bannink, A., France, J., Kebreab, S., and van Gastelen. (2018b). Antimethanogenic effects of 3-nitrooxypropanol depend on supplementation dose, dietary fiber content, cattle type. J. Dairy Sci. 101, 9041–9047. doi: 10.3168/jds.2018-14456

Dijkstra, J., Oenema, O., Van Groenigen, J., Spek, J., Van Vuuren, A., and Bannink, A. (2013). Diet effects on urine composition of cattle and N2O emissions. Animal 7(Suppl 2):292–302. doi: 10.1017/S1751731113000578

Doreau, M., Rochette, Y., and Martin, C. (2012). Effect of type of forage (maize silage vs grass silage) and protein source (soybean meal vs dehydrated lucerne) in dairy cow diet on methane emission and on nitrogen losses. In: Proc. International Symposium on Emission of Gas and Dust From Livestock . Saint-Malo.

Duan, Y., Awasthi, S. K., Liu, T., Verma, S., Wang, Q., Chen, H., et al. (2019). Positive impact of biochar alone and combined with bacterial consortium amendment on improvement of bacterial community during cow manure composting. Bioresour. Technol. 280, 79–87. doi: 10.1016/j.biortech.2019.02.026

Duin, E. C., Wagner, T., Shima, S., Prakash, D., Cronin, B., Yáñez-Ruiz, D. R., et al. (2016). Mode of action uncovered for the specific reduction of methane emissions from ruminants by the small molecule 3-nitrooxypropanol. Proc. Nat. Acad. Sci. U.S.A. 113, 6172–6177. doi: 10.1073/pnas.1600298113

Dustan, A. (2002). Review of Methane and Nitrous Oxide Emission Factors for Manure Management in Cold Climates. JTI-rapport 299. Uppsala: Instituet for jordbruks - och miljoeteknik, JTI.

Edouard, N., Charpiot, A., Robin, P., Lorinquer, E., Dollé, J. B., and Faverdin, P. (2019). Influence of diet and manure management on ammonia and greenhouse gas emissions from dairy barns. Animal 13, 2903–2912. doi: 10.1017/S1751731119001368

Elcoso, G., Zweifel, B., and Bach, A. (2019). Effects of a blend of essential oils on milk yield and feed efficiency of lactating dairy cows. Appl. Animal Sci. 35, 304–311. doi: 10.15232/aas.2018-01825

Ellis, J. L., Dijkstra, J., Kebreab, E., Bannink, A., Odongo, N. E., McBride, B. W., et al. (2008). Aspects of rumen microbiology central to mechanistic modelling of methane production in cattle. J. Agric. Sci. 146, 213–233. doi: 10.1017/S0021859608007752

Fang, M., Wong, J., Ma, K., and Wong, M. H. (1999). Co-composting of sewage sludge and coal fly ash: nutrient transformations. Bioresour. Technol. 67, 19–24. doi: 10.1016/S0960-8524(99)00095-4

FAO (2009). “Milk/dairy products,” in Agribusiness Handbook . Rome: Food and Agriculture Organization of the United Nations.

FAO, F. (1997). FAOSTAT Statistical Database . FAO: Rome.

Febrisiantosa, A., Ravindran, B., and Choi, H. (2018). The effect of co-additives (Biochar and FGD Gypsum) on ammonia volatilization during the composting of livestock waste. Sustainability 10:795. doi: 10.3390/su10030795

Filipy, J., Rumburg, B., Mount, G., Westberg, H., and Lamb, B. (2006). Identification and quantification of volatile organic compounds from a dairy. Atmos. Environ. 40, 1480–1494. doi: 10.1016/j.atmosenv.2005.10.048

Gerber, P. J., Henderson, B., and Makkar, H. P. (2013). Mitigation of greenhouse gas emissions in livestock production: a review of technical options for non-CO 2 emissions. No. 177. Food and Agriculture Organization of the United Nations (FAO).

Gil, Á., and Ortega, R. M. (2019). Introduction and executive summary of the supplement, role of milk and dairy products in health and prevention of noncommunicable chronic diseases: a series of systematic reviews. Adv. Nutrition 10, S67–S73. doi: 10.1093/advances/nmz020

Godlewska, P., Schmidt, H. P., Ok, Y. S., and Oleszczuk, P. (2017). Biochar for composting improvement and contaminants reduction. A review. Bioresource Tech. 246, 193–202. doi: 10.1016/j.biortech.2017.07.095

Guo, X., Huang, J., Lu, Y., Shan, G., and Li, Q. (2016). The influence of flue gas desulphurization gypsum additive on characteristics and evolution of humic substance during co-composting of dairy manure and sugarcane pressmud. Bioresour. Technol. 219, 169–174. doi: 10.1016/j.biortech.2016.07.125

Guyader, J., Eugène, M., Doreau, M., Morgavi, D., Gérard, C., Loncke, C., et al. (2015). Nitrate but not tea saponin feed additives decreased enteric methane emissions in nonlactating cows. J. Anim. Sci. 93, 5367–5377. doi: 10.2527/jas.2015-9367

Haisan, J., Sun, Y., Guan, L., Beauchemin, K. A., Iwaasa, A., Duval, S., et al. (2017). The effects of feeding 3-nitrooxypropanol at two doses on milk production, rumen fermentation, plasma metabolites, nutrient digestibility, and methane emissions in lactating Holstein cows. Animal Produc. Sci. 57, 282–289. doi: 10.1071/AN15219

Hao, X., Larney, F. J., Chang, C., Travis, G. R., Nichol, C. K., and Bremer, E. (2005). The effect of phosphogypsum on greenhouse gas emissions during cattle manure composting. J. Environ. Qual. 34, 774–781. doi: 10.2134/jeq2004.0388

Hart, K. J., Jones, H. G., Waddams, K. E., Worgan, H. J., Zweifel, B., and Newbold, C. J. (2019). An essential oil blend decreases methane emissions and increases milk yield in dairy cows. Open J. Animal Sci. 9:259. doi: 10.4236/ojas.2019.93022

He, S., Fan, X., Katukuri, N. R., Yuan, X. F., and Wang, R.-B. (2016). Enhanced methane production from microalgal biomass by anaerobic bio-pretreatment. Bioresour. Technol. 204, 145–151. doi: 10.1016/j.biortech.2015.12.073

He, X., Yin, H., Han, L., Cui, R., Fang, C., and Huang, G. (2019). Effects of biochar size and type on gaseous emissions during pig manure/wheat straw aerobic composting: Insights into multivariate-microscale characterization and microbial mechanism. Bioresour. Technol. 271, 375–382. doi: 10.1016/j.biortech.2018.09.104

Herrero, M., Grace, D., Njuki, J., Johnson, N., Enahoro, D., Silvestri, S., et al. (2013). The roles of livestock in developing countries. Animal 7:3. doi: 10.1017/S1751731112001954

Hindrichsen, I., Wettstein, H.-R., Machmüller, A., and Kreuzer, M. (2006). Methane emission, nutrient degradation and nitrogen turnover in dairy cows and their slurry at different milk production scenarios with and without concentrate supplementation. Agric. Ecosyst. Environ. 113, 150–161. doi: 10.1016/j.agee.2005.09.004

Hirahatake, K. M., Slavin, J. L., Maki, K. C., and Adams, S. H. (2014). Associations between dairy foods, diabetes, and metabolic health: potential mechanisms and future directions. Metab. Clin. Exp. 63, 618–627. doi: 10.1016/j.metabol.2014.02.009

Holland, E. (2017). Investigation of Ammonia and Nitrate Removal from Municipal Wastewater Using BiOWiSH .

Hristov, A. N., Bannink, A., Crompton, L. A., Huhtanen, P., Kreuzer, M., McGee, M., et al. (2019). Invited review: nitrogen in ruminant nutrition: a review of measurement techniques. J. Dairy Sci. 102, 5811–5852. doi: 10.3168/jds.2018-15829

Hristov, A. N., Hanigan, M., Cole, A., Todd, R., McAllister, T. A., Ndegwa, P. M., et al. (2011). Ammonia emissions from dairy farms and beef feedlots. Can. J. Anim. Sci. 91, 1–35. doi: 10.4141/CJAS10034

Hristov, A. N., Lee, C., Cassidy, T., Heyler, K., Tekippe, J., Varga, G., et al. (2013a). Effect of Origanum vulgare L. leaves on rumen fermentation, production, and milk fatty acid composition in lactating dairy cows. J. Dairy Sci. 96, 1189–1202. doi: 10.3168/jds.2012-5975

Hristov, A. N., Oh, J., Firkins, J., Dijkstra, J., Kebreab, E., Waghorn, G., et al. (2013b). Special topics—Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options. J. Animal Sci. 91, 5045–5069. doi: 10.2527/jas.2013-6583

Hristov, A. N., Oh, J., Giallongo, F., Frederick, T. W., Harper, M. T., Weeks, H. L., et al. (2015). An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production. Proc. Nat. Acad. Sci. U.S.A. 112, 10663–10668. doi: 10.1073/pnas.1504124112

Hungate, R. E. (2013). The Rumen and Its Microbes . New York: Elsevier.

Immig, I. (1996). The rumen and hindgut as source of ruminant methanogenesis. Environ. Monit. Assess. 42, 57–72. doi: 10.1007/BF00394042

IPCC (2014). Climate Change 2014: Synthesis Report . Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC, Geneva, Switzerland.

Ivan, M., Mir, P., Mir, Z., Entz, T., He, M., and McAllister, T. (2004). Effects of dietary sunflower seeds on rumen protozoa and growth of lambs. Br. J. Nutrition 92, 303–310. doi: 10.1079/BJN20041178

Janssen, P. H., and Kirs, M. (2008). Structure of the archaeal community of the rumen. Appl. Environ. Microbiol. 74, 3619–3625. doi: 10.1128/AEM.02812-07

Jayanegara, A., Leiber, F., and Kreuzer, M. (2012). Meta-analysis of the relationship between dietary tannin level and methane formation in ruminants from in vivo and in vitro experiments. J. Anim. Physiol. Anim. Nutr. 96, 365–375. doi: 10.1111/j.1439-0396.2011.01172.x

Jindo, K., Sánchez-Monedero, M. A., Hernández, T., García, C., Furukawa, T., Matsumoto, K., et al. (2012). Biochar influences the microbial community structure during manure composting with agricultural wastes. Sci. Total Environ. 416, 476–481. doi: 10.1016/j.scitotenv.2011.12.009

Johnson, D., Phetteplace, H., and Seidl, A. (2002). Methane, Nitrous Oxide and Carbon Dioxide Emissions From Ruminant Livestock Production Systems . Elsevier; Amsterdam: The Netherlands 77–85.

Johnson, K. A., and Johnson, D. E. (1995). Methane emissions from cattle. J. Anim. Sci. 73:2483–2492. doi: 10.2527/1995.7382483x

Juodeikiene, G., Cizeikiene, D., Glasner, C., Bartkiene, E., Dikiy, A., Shumilina, E., et al. (2017). Evaluation of the potential of utilizing lactic acid bacteria and dairy wastewaters for methane production. Energy Explor. Exploitation 35, 388–402. doi: 10.1177/0144598717698081

Kaspar, H., and Tiedje, J. (1981). Dissimilatory reduction of nitrate and nitrite in the bovine rumen: nitrous oxide production and effect of acetylene. Appl. Environ. Microbiol. 41, 705–709. doi: 10.1128/aem.41.3.705-709.1981

Klop, G., Dijkstra, J., Dieho, K., Hendriks, W., and Bannink, A. (2017a). Enteric methane production in lactating dairy cows with continuous feeding of essential oils or rotational feeding of essential oils and lauric acid. J. Dairy Sci. 100, 3563–3575. doi: 10.3168/jds.2016-12033

Klop, G., Hatew, B., Bannink, A., and Dijkstra, J. (2016). Feeding nitrate and docosahexaenoic acid affects enteric methane production and milk fatty acid composition in lactating dairy cows. J. Dairy Sci. 99, 1161–1172. doi: 10.3168/jds.2015-10214

Klop, G., Van Laar-van Schuppen, S., Pellikaan, W, Hendriks, W., Bannink, A., and Dijkstra, J. (2017b). Changes in in vitro gas and methane production from rumen fluid from dairy cows during adaptation to feed additives in vivo . Animal 11, 591–599. doi: 10.1017/S1751731116002019

Knapp, J. R., Laur, G., Vadas, P. A., Weiss, W. P., and Tricarico, J. M. (2014). Invited review: enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions. J. Dairy Sci. 97, 3231–3261. doi: 10.3168/jds.2013-7234

Knips, V. (2005). Developing Countries and the Global Dairy Sector Part I global Overview .

Knowlton, K., and Cobb, T. D. (2006). ADSA Foundation Scholar Award: implementing waste solutions for dairy and livestock farms. J. Dairy Sci. 89, 1372–1383. doi: 10.3168/jds.S0022-0302(06)72205-6

Kreuzer, M., and Hindrichsen, I. (2006). “Methane mitigation in ruminants by dietary means: the role of their methane emission from manure,” in Proc. International Congress Series . Zurich: Elsevier 199–208. doi: 10.1016/j.ics.2006.01.015

Külling, D., Menzi, H., Sutter, F., Lischer, P., and Kreuzer, M. (2003). Ammonia, nitrous oxide and methane emissions from differently stored dairy manure derived from grass-and hay-based rations. Nutrient Cycling Agroecosyst. 65, 13–22. doi: 10.1023/A:1021857122265

Lee, C., and Beauchemin, K. A. (2014). A review of feeding supplementary nitrate to ruminant animals: nitrate toxicity, methane emissions, production performance. Can. J. Anim. Sci. 94, 557–570. doi: 10.4141/cjas-2014-069

Lee, C., Hristov, A. N., Dell, C. J., Feyereisen, G., Kaye, J., and Beegle, D. (2012). Effect of dietary protein concentration on ammonia and greenhouse gas emitting potential of dairy manure. J. Dairy Sci. 95, 1930–1941. doi: 10.3168/jds.2010-4141

Lee, E. (2012). Investigation of a commercial product (BiOWiSH TM) for nitrogen management (Masters thesis). California Polytechnic State University San Luis Obispo; CalPoly Digital Commons.

Leng, R., and Preston, T. (2010). Further considerations of the potential of nitrate as a high affinity electron acceptor to lower enteric methane production in ruminants. Livestock Res. Rural Dev. 22:221.

Li, R., Wang, Q., Zhang, Z., Zhang, G., Li, Z., Wang, L., et al. (2015). Nutrient transformation during aerobic composting of pig manure with biochar prepared at different temperatures. Environ. Technol. 36, 815–826. doi: 10.1080/09593330.2014.963692

Li, Y., Luo, W., Li, G., Wang, K., and Gong, X. (2018). Performance of phosphogypsum and calcium magnesium phosphate fertilizer for nitrogen conservation in pig manure composting. Bioresour. Technol. 250, 53–59. doi: 10.1016/j.biortech.2017.07.172

Lopes, J., de Matos, L., Harper, M., Giallongo, F., Oh, J., Gruen, D., et al. (2016). Effect of 3-nitrooxypropanol on methane and hydrogen emissions, methane isotopic signature, and ruminal fermentation in dairy cows. J. Dairy Sci. 99, 5335–5344. doi: 10.3168/jds.2015-10832

Lovett, D., Shalloo, L., Dillon, P., and O'Mara, F. (2006). A systems approach to quantify greenhouse gas fluxes from pastoral dairy production as affected by management regime. Agric. Syst. 88, 156–179. doi: 10.1016/j.agsy.2005.03.006

Lund, P., Dahl, R., Yang, H., Hellwing, A. L. F., Cao, B., and Weisbjerg, M. R. (2014). The acute effect of addition of nitrate on in vitro and in vivo methane emission in dairy cows. Animal Produc. Sci. 54, 1432–1435. doi: 10.1071/AN14339

Madureira, A., Tavares, T., Gomes, A. M., Pintado, M., and Malcata, F. X. (2010). Invited review: physiological properties of bioactive peptides obtained from whey proteins. J. Dairy Sci. 93, 437–455. doi: 10.3168/jds.2009-2566

Mao, H., Lv, Z., Sun, H., Li, R., Zhai, B., Wang, Z., et al. (2018). Improvement of biochar and bacterial powder addition on gaseous emission and bacterial community in pig manure compost. Bioresour. Technol. 258, 195–202. doi: 10.1016/j.biortech.2018.02.082

Mao, H., Zhang, T., Li, R., Zhai, B., Wang, Z., Wang, Q., et al. (2017). Apple pomace improves the quality of pig manure aerobic compost by reducing emissions of NH 3 and N 2 O. Sci. Rep. 7:13537. doi: 10.1038/s41598-017-00987-y

Martínez-Fernández, G., Abecia, L., Arco, A., Cantalapiedra-Hijar, G., Martín-García, A., Molina-Alcaide, E., et al. (2014). Effects of ethyl-3-nitrooxy propionate and 3-nitrooxypropanol on ruminal fermentation, microbial abundance, and methane emissions in sheep. J. Dairy Sci. 97, 3790–3799. doi: 10.3168/jds.2013-7398

McCaughey, W., Wittenberg, K., and Corrigan, D. (1999). Impact of pasture type on methane production by lactating beef cows. Can. J. Anim. Sci. 79, 221–226. doi: 10.4141/A98-107

Meller, R., Wenner, B., Ashworth, J., Gehman, A., Lakritz, J., and Firkins, J. (2019). Potential roles of nitrate and live yeast culture in suppressing methane emission and influencing ruminal fermentation, digestibility, and milk production in lactating Jersey cows. J. Dairy Sci. 102, 6144–6156. doi: 10.3168/jds.2018-16008

Milani, F., Nutter, D., and Thoma, G. (2011). Invited review: environmental impacts of dairy processing and products: a review. J. Dairy Sci. 94, 4243–4254. doi: 10.3168/jds.2010-3955

Miller, L., Moorby, J. M., Davies, D. R., Humphreys, M. O., Scollan, N. D., MacRae, J. C., et al. (2001). Increased concentration of water-soluble carbohydrate in perennial ryegrass ( Lolium perenne L.): milk production from late-lactation dairy cows. Grass Forage Sci. 56, 383–394. doi: 10.1046/j.1365-2494.2001.00288.x

Mills, J., Crompton, L., and Reynolds, C. (2008). Ruminant Nutrition Regimes to Reduce Methane and Nitrogen Emissions—a Meta-Analysis of Current Databases . Final Project Report 1600:04.

Moe, P., and Tyrrell, H. (1979). Methane production in dairy cows. J. Dairy Sci. 62, 1583–1586. doi: 10.3168/jds.S0022-0302(79)83465-7

Muck, R. E. (1982). Urease activity in bovine feces. J. Dairy Sci. 65, 2157–2163. doi: 10.3168/jds.S0022-0302(82)82475-2

Murray, R., Bryant, A., and Leng, R. (1976). Rates of production of methane in the rumen and large intestine of sheep. Br. J. Nutrition 36, 1–14. doi: 10.1079/BJN19760053

Naranjo, A., Johnson, A., Rossow, H., and Kebreab, E. (2020). Greenhouse gas, water, and land footprint per unit of production of the California dairy industry over 50 years. J. Dairy Sci . doi: 10.3168/jds.2019-16576

National Research Council N. (2001). Nutrient Requirements of Dairy Cattle, 7th Edn. Washington, DC: The National Academies Press.

O'Keefe, M. (2018). Data: Dairy's Positive Impact on U.S. Economy. Vol. 2020. U.S. Dairy Export Council.

Outlook, F. (2020). Biannual Report on Global Food Markets [Electronic Resource]. Food and Agriculture Organization of the United Nations.

Pal, N. (2012). A white paper on Effect and Efficacy of BiOWiSHTM for Reducing Solids in Dairy Wastewater. [Electronic Resource] . Available online at: https://cead874f5bbdd4b43a5cfad5b9385501cb7f7cac4f09f1c56222.ssl.cf5.rackcdn.com/White%20Papers/cal-poly-wwt-white-paper-dairy-manure.pdf

Parsons, A., Rowarth, J., and Rasmussen, S. (2012). High-sugar grasses. Plant Sci. Rev. 2011:187. doi: 10.1079/PAVSNNR20116046

Peterson, C. B., El Mashad, H. M., Zhao, Y., Pan, Y., and Mitloehner, F. M. (2020). Effects of SOP lagoon additive on gaseous emissions from stored liquid dairy manure. Sustainability 12:1393. doi: 10.3390/su12041393

Pinares-Patiño, C., Baumont, R., and Martin, C. (2003). Methane emissions by Charolais cows grazing a monospecific pasture of timothy at four stages of maturity. Can. J. Anim. Sci. 83, 769–777. doi: 10.4141/A03-034

Place, S. E., and Mitloehner, F. (2010). Invited review: contemporary environmental issues: a review of the dairy industry's role in climate change and air quality and the potential of mitigation through improved production efficiency. J. Dairy Sci. 93, 3407–3416. doi: 10.3168/jds.2009-2719

Pryce, J. E., and Haile-Mariam, M. (2020). Symposium review: genomic selection for reducing environmental impact and adapting to climate change. J. Dairy Sci . doi: 10.3168/jds.2019-17732

Reynolds, C. K., Humphries, D. J., Kirton, P., Kindermann, M., Duval, S., and Steinberg, W. (2014). Effects of 3-nitrooxypropanol on methane emission, digestion, and energy and nitrogen balance of lactating dairy cows. J. Dairy Sci. 97, 3777–3789. doi: 10.3168/jds.2013-7397

Rodriguez Chiang, L. M. (2011). Methane Potential of Sewage Sludge to Increase Biogas Production .

Romero-Perez, A., Okine, E., McGinn, S., Guan, L., Oba, M., Duval, S., et al. (2015). Sustained reduction in methane production from long-term addition of 3-nitrooxypropanol to a beef cattle diet. J. Anim. Sci. 93, 1780–1791. doi: 10.2527/jas.2014-8726

Santos, M., Robinson, P., Williams, P., and Losa, R. (2010). Effects of addition of an essential oil complex to the diet of lactating dairy cows on whole tract digestion of nutrients and productive performance. Anim. Feed Sci. Technol. 157, 64–71. doi: 10.1016/j.anifeedsci.2010.02.001

Shaw, S. L., Mitloehner, F. M., Jackson, W., DePeters, E. J., Fadel, J. G., Robinson, P. H., et al. (2007). Volatile organic compound emissions from dairy cows and their waste as measured by proton-transfer-reaction mass spectrometry. Environ. Sci. Tech. 41, 1310–1316. doi: 10.1021/es061475e

Siekmann, J. H., Allen, L. H., Bwibo, N. O., Demment, M. W., Murphy, S. P., and Neumann, C. G. (2003). Kenyan school children have multiple micronutrient deficiencies, but increased plasma vitamin B-12 is the only detectable micronutrient response to meat or milk supplementation. J. Nutrition 133, 3972S–3980S. doi: 10.1093/jn/133.11.3972S

Steinfeld, H., Gerber, P., Wassenaar, T., Castel, V., Rosales, M. M., de Haan, C., et al. (2006). Livestock's Long Shadow: Environmental Issues and Options . Food and Agriculture Org.

Sumner, D. A., and Matthews, W. A. (2019). Contributions of the California Dairy Industry to the California Economy in 2018 . University of California, Agricultural Issues Center.

Sun, H., Pan, Y., Zhao, Y., Jackson, W. A., Nuckles, L. M., Malkina, I. L., et al. (2008). Effects of sodium bisulfate on alcohol, amine, and ammonia emissions from dairy slurry. J. Environ. Qual. 37, 608–614. doi: 10.2134/jeq2006.0446

Tavendale, M. H., Meagher, L. P., Pacheco, D., Walker, N., Attwood, G. T., and Sivakumaran, S. (2005). Methane production from in vitro rumen incubations with Lotus pedunculatus and Medicago sativa, and effects of extractable condensed tannin fractions on methanogenesis. Anim. Feed Sci. Technol. 123, 403–419. doi: 10.1016/j.anifeedsci.2005.04.037

Tekippe, J., Hristov, A. N., Heyler, K., Cassidy, T., Zheljazkov, V., Ferreira, J., et al. (2011). Rumen fermentation and production effects of Origanum vulgare L. leaves in lactating dairy cows. J. Dairy Sci. 94, 5065–5079. doi: 10.3168/jds.2010-4095

Thorning, T. K., Raben, A., Tholstrup, T., Soedamah-Muthu, S. S., Givens, I., and Astrup, A. (2016). Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence. Food Nutrition Res. 60:32527. doi: 10.3402/fnr.v60.32527

Tubail, K., Chen, L., Michel Jr, F. C., Keener, H. M., Rigot, J. F., Klingman, M., et al. (2008). Gypsum additions reduce ammonia nitrogen losses during composting of dairy manure and biosolids. Compost Sci. Utilization 16, 285–293. doi: 10.1080/1065657X.2008.10702390

USDA (2020). Milk Production. National Agricultural Statistics Service, United States Department of Agriculture (2020).

Van Zijderveld, S., Gerrits, W., Dijkstra, J., Newbold, J., Hulshof, R., and Perdok, H. (2011). Persistency of methane mitigation by dietary nitrate supplementation in dairy cows. J. Dairy Sci. 94, 4028–4038. doi: 10.3168/jds.2011-4236

Vandecasteele, B., Sinicco, T., D'Hose, T., Nest, T. V., and Mondini, C. (2016). Biochar amendment before or after composting affects compost quality and N losses, but not P plant uptake. J. Environ. Manage. 168, 200–209. doi: 10.1016/j.jenvman.2015.11.045

Velthof, G., Van Beusichem, M., and Oenema, O. (1998). “Mitigation of nitrous oxide emission from dairy farming systems,” in Nitrogen, the Confer-Ns (Noordwijkerhout: Elsevier), 173–178. doi: 10.1016/B978-0-08-043201-4.50028-9

Visioli, F., and Strata, A. (2014). Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence. Adv. Nutr. 5, 131–143. doi: 10.3945/an.113.005025

Von Keyserlingk, M., Martin, N., Kebreab, E., Knowlton, K., Grant, R., Stephenson, M., et al. (2013). Invited review: sustainability of the US dairy industry. J. Dairy Sci. 96, 5405–5425. doi: 10.3168/jds.2012-6354

Vyas, D., McGinn, S., Duval, S., Kindermann, M., and Beauchemin, K. (2016). Effects of sustained reduction of enteric methane emissions with dietary supplementation of 3-nitrooxypropanol on growth performance of growing and finishing beef cattle. J. Anim. Sci. 94, 2024–2034. doi: 10.2527/jas.2015-0268

Waghorn, G. (2008). Beneficial and detrimental effects of dietary condensed tannins for sustainable sheep and goat production—Progress and challenges. Anim. Feed Sci. Technol. 147, 116–139. doi: 10.1016/j.anifeedsci.2007.09.013

Wang, M., Awasthi, M. K., Wang, Q., Chen, H., Ren, X., Zhao, J., et al. (2017). Comparison of additives amendment for mitigation of greenhouse gases and ammonia emission during sewage sludge co-composting based on correlation analysis. Bioresour. Technol. 243, 520–527. doi: 10.1016/j.biortech.2017.06.158

Wang, Q., Wang, Z., Awasthi, M. K., Jiang, Y., Li, R., Ren, X., et al. (2016). Evaluation of medical stone amendment for the reduction of nitrogen loss and bioavailability of heavy metals during pig manure composting. Bioresour. Technol. 220, 297–304. doi: 10.1016/j.biortech.2016.08.081

Wolf, C. A. (2003). The economics of dairy production. Vet. Clinics 19, 271–293. doi: 10.1016/S0749-0720(03)00028-8

Wong, J. W.-C., Fung, S. O., and Selvam, A. (2009). Coal fly ash and lime addition enhances the rate and efficiency of decomposition of food waste during composting. Bioresour. Technol. 100, 3324–3331. doi: 10.1016/j.biortech.2009.01.063

Woodward, S., Waghorn, G., Lassey, K., and Laboyrie, P. (2002). “Does feeding sulla (Hedysarum coronarium) reduce methane emissions from dairy cows?,” in Proc. Proceedings-New Zealand Society of Animal Production . New Zealand Society of Animal Production (1999). p. 227–230.

Wu, H., Lai, C., Zeng, G., Liang, J., Chen, J., Xu, J., et al. (2017). The interactions of composting and biochar and their implications for soil amendment and pollution remediation: a review. Crit. Rev. Biotechnol. 37, 754–764. doi: 10.1080/07388551.2016.1232696

Xu, W., Fu, S., Yang, Z., Lu, J., and Guo, R. (2018). Improved methane production from corn straw by microaerobic pretreatment with a pure bacteria system. Bioresour. Technol. 259, 18–23. doi: 10.1016/j.biortech.2018.02.046

Yang, F., Li, G., Shi, H., and Wang, Y. (2015). Effects of phosphogypsum and superphosphate on compost maturity and gaseous emissions during kitchen waste composting. Waste Manage 36, 70–76. doi: 10.1016/j.wasman.2014.11.012

Keywords: cows, sustainability, greenhouse gases, methane, ammonia, enteric emissions, waste emissions

Citation: Peterson CB and Mitloehner FM (2021) Sustainability of the Dairy Industry: Emissions and Mitigation Opportunities. Front. Anim. Sci. 2:760310. doi: 10.3389/fanim.2021.760310

Received: 18 August 2021; Accepted: 17 September 2021; Published: 18 October 2021.

Reviewed by:

Copyright © 2021 Peterson and Mitloehner. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Frank M. Mitloehner, Zm1taXRsb2VobmVyJiN4MDAwNDA7dWNkYXZpcy5lZHU=

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Sustainability in the dairy industry: a systematic literature review

Affiliations.

• 1 Universidade do Vale do Taquari - Univates, Lajeado, Rio Grande do Sul, Brazil. [email protected].
• 2 Universidade Feevale, Novo Hamburgo, Rio Grande do Sul, Brazil.
• 3 Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul, campus Caxias do Sul, Caxias do Sul, RS, Brazil.
• 4 Universidade do Vale do Taquari - Univates, Lajeado, Rio Grande do Sul, Brazil.
• 5 Universidade Federal de Pelotas (UFPEL), Pelotas, Rio Grande do Sul, Brazil.
• PMID: 32566986
• DOI: 10.1007/s11356-020-09316-9

The dairy industry can contribute to global food security in a sustainable way by efficiently converting milk into dairy ingredients and products, even though they are polluting on a large scale. In this context, this study aimed to conduct a systematic literature review on sustainable indicators and dairy industries. The methodology used has a qualitative and quantitative approach and its technical procedure was the systematic literature review. The bases of journals consulted, using the keywords "sustainability indicator" and "dairy industry" which resulted in 130 valid scientific articles. The main results show that the sustainability indicators in the dairy industry are emerging and lacking research; being found seven papers, that highlight 12 indicators of the environmental, 11 of the social and eight economic dimensions, that may be considered fragile and initial. The studied problems are related to wastewater treatment methods, electric power consumption, efficiency of the industrial plant, among others, and the benefits on the theme are related to solutions to the difficulties, such as electricity reduction, sustainable practices. Among others, it is concluded that the dairy industries address the sustainability theme since 2011, with an ambiguous trend, being found evidence of the fragility of the sustainability indicators was found, mainly in the initial stage of their conception, when considering holistic approach (triple bottom line).

Keywords: Cleaner production; Dairy industry; Environmental science; Indicators; Milk; Sustainability.

Publication types

• Systematic Review
• Environmental Pollutants*
• Food Supply
• Environmental Pollutants
• Waste Water

Grants and funding

• 428860/2018-4/Conselho Nacional de Desenvolvimento Científico e Tecnológico