Recommendation 3-1

In view of the anticipated continuing increased demand for animal protein, growth in U.S. research related to animal agricultural productivity is imperative. Animal protein products contribute over $43 billion annually to the U.S. agricultural trade balance. Animal agriculture accounts for 60 to 70 percent of the total agricultural economy. In the past two decades, public funding, including formula funding and USDA ARS/NIFA funding, of animal science research has been stagnant in terms of real dollars and has declined in relation to the research inflation rate. A 50 percent decline in the rate of increase in U.S. agricultural productivity is predicted if overall agricultural funding increases in normative dollars continue at the current rate, which is less than the expected rate of inflation of research costs. If funding does meet the rate of research cost inflation, however, a 73 percent increase in overall agricultural productivity between now and 2050 is projected and a 1 percent increase in inflation-adjusted spending is projected to lead to an 83 percent increase.

Despite documenting the clear economic and scientific value of animal science research in the United States, funding to support the infrastructure and capacity is evidently insufficient to meet the needs for animal food; U.S.-based research will be needed to address sustainability issues and to help developing countries sustainably increase their own animal protein production and/or needs. Additionally, animal science research and practices in the United States are often adopted, to the extent possible, within developing countries. Thus, increases in U.S. funding will favorably impact animal production enterprises in developing countries.

With the lack of increase in public funding of animal science research, private/industry support has increased. The focus of industry funding is more toward applied areas that can be commercialized in the short term. Many of these applications are built on concepts developed from publicly funded basic research. With the increased animal protein demands, especially poultry, more publicly funded basic research is needed.

To meet current and future animal protein demand, and to sustain corresponding infrastructure and capacity, public support for animal science research (especially basic research) should be restored to at least past levels of real dollars and maintained at a rate that meets or exceeds the annual rate of research inflation. This is especially critical for those species (i.e., poultry) for which consumer demand is projected to significantly increase by 2050 and for those species with the greatest opportunity for reducing the environmental impact of animal agriculture.

Priorities for Research Support

USDA ARS spends 50 percent more on crop research and a greater percentage of its budget on food safety and nutrition and environmental stewardship than on animal production research. In addition, in the past couple of decades, public funding (USDA ARS/NIFA) of animal science research has been declining in terms of real dollars. One priority for research support in this area includes:

• USDA through its relevant agencies is encouraged to maintain high priority for funding for research, including translational research, that is commensurate with the future needs of livestock protein. USDA should maintain and enhance the current link to the livestock, poultry, and aquaculture industries in the United States with the aim of building better public–private partnerships in funding research in animal science.

Other Research Priorities

Technological advancements in the animal protein production system, including genetics, breeding, reproduction, nutrition, animal health and welfare, management, food and feed safety, and food product quality, have been critical to improvements in the production of more environmentally friendly and sustainable animal protein products. One research priority in this area includes:

• Research in sustainable intensification should continue to focus on land, energy, water, and nitrogen utilization. The relevant U.S. government agencies should build a professional interagency network with the aim of maintaining sustainable animal production systems.

3-3 Genetics, Genomics, and Reproduction

The genetics of animal species has far-ranging effects in animal agriculture, including reproductive performance, farm economics, productivity, and environmental impacts. Johnson and Ruttan (1997) suggested that the adoption of breeding technologies has been the most significant factor contributing to farm animal productivity, including livestock and poultry, since the 1940s. Adoption of advanced breeding technologies has resulted in positive impacts on farm profits and milk produced per cow, but has negatively impacted cost of production (Khanal and Gillespie, 2013). Animal breeders have effectively manipulated the genomes of food animal species by using the natural variation that exists within a species. Traditional breeding was done in the past in the absence of molecular knowledge of the genes acting on a quantitative locus, and although much progress has been made, efficiency decreases when traits such as fertility, longevity, feed efficiency and disease resistance are difficult to measure and have a low heritability (Eggen, 2012). Selection for these traits must be accomplished using genomic selection, which will require high-quality phenotypic data from animals.

The application of genomics to the design and implementation of animal and poultry breeding programs is now being actively implemented, and the costs of genomic selection tools have greatly declined in recent years. Combined selection for growth, body composition, and feed efficiency continues to deliver 2-3 percent improvement per year in the efficiency of meat production (Gous, 2010), and milk yields will continue to increase by 110 kg per cow per year (Eggen, 2012). Commercial breeding goals in poultry and pigs has widened considerably since the 1970s, with the number of genetic traits now typically between 30 and 40 (Neeteson-van Nieuwenhoven et al., 2013). Continued movement away from single-production trait selection (e.g., milk yield) toward more indices that take into account animal reproductive performance, animal behavior, animal welfare, form and function, adaptability to environmental change, and longevity will be critical for advancing the sustainability of animal agriculture. Currently, the genome, transcriptome, epigenome, and the metagenome of many species are being investigated by high-throughput sequencing methods. Benefits are already being reported in the improvement of beef quality (e.g., tenderness, marbling) and muscle development or growth (Box 3-8, Hocquette et al., 2007).

BOX 3-8

Applying Innovations in Genomic Selection to Animal Breeding Programs. Technological developments in genomics are being directly applied in livestock breeding programs, facilitating greater certainty and efficacy in promoting beneficial genetic traits (more...)

Epigenetics is a newer field in animal science investigating the changes in gene expression, not from alterations of DNA sequence, but rather changes in chromatin structure (Funston and Summers, 2013). These changes reflect broad environmental influences that add methyl groups or other structural elements to DNA beyond those involved in basic inheritance. As such, epigenetics can be considered to reflect the effects of nurture on chromosomal activities, which is a way to understand the cumulative exposure to chemical and nonchemical stressors in humans (Olden et al., 2014). Although research has investigated fetal and neonatal programming due to nutritional differences (Soberon et al., 2012; Funston and Summers, 2013), further research is needed to understand the underlying mechanisms of epigenetics and advances in statistics, bioinformatics, and computational biology (Gonzalez-Recio, 2011). Linking researchers with these basic skills to other animal scientists will help bridge gaps between the “omics” and the whole animal. Additionally, longer-term, multigenerational production systems research (particularly for extensive animal production systems) is required to reveal potential epigenetic effects, while simultaneously evaluating the environmental, social, and economic sustainability of different production systems.

Emphasis on recent funding has been placed on genomic information and tools, whereas fundamental research on the biology of birds has been neglected (Fulton, 2012). Poultry genetic diversity is needed to better understand gene function and the effects of variation on traits. The tremendous loss of farm animal diversity on a commercial level in the United States needs to be reversed. Microbial genomics is an area that has the potential to transform the breeding industry because adjustments of the microflora could reduce environmental impacts and improve sustainability. As geneticists continue to make improvements in broiler and layer performance, there will be more emphasis on bird welfare and the ability to cope with widely different environments, especially heat tolerance and dissipation (Gous, 2010).

Green (2009) reviewed the role of animal breeders and the challenges they will face in the genomics era. He suggested that animal breeders will need to lead the way in the integration of genomic and phenotypic data. There will be a need to better understand how the interactions of genes, proteins, mechanisms, and the external environment produce the phenotype of an animal. To accomplish this, animal breeders will need to work with colleagues in physiology, nutrition, muscle biology, growth and development, lactation, immunology, microbiology and economics. The challenge is articulated by Green (2009) in the following quote:

The reduction in number of academic animal breeding programs around the world, and particularly in North America, has resulted in a deficit of human talent and resources ready to take on these challenges. Not only are quantitative geneticists lacking, those few who are being produced in the remaining programs are entering a highly competitive job market where few are remaining in academia, with many of the trained animal breeding scientists being pulled into the plant and biomedical arenas. The need to rebuild infrastructure for developing scientists and expertise in the animal breeding area is critical and must be addressed through new strategies and models. More direct investment of private industry into the funding of these programs is beginning to occur and will need to increase in the near term. Increased reach of federal research programs into the education sector is also needed, principally through the increased availability of research funding in USDA-ARS for graduate student and postdoctoral training. The time may have come for U.S. programs to break down past barriers that have prevented consortia-type funding so that large-scale, common sense interdependent partnerships can be instituted between federal and state agencies, universities, the private sector, and industry commodity organizations. This model has certainly had success in other areas of the world, and the area of animal breeding is one that could benefit greatly from such approaches. Finally, because of the rapid escalation in the development of genome- and phenome-based technologies, the need for public education and outreach efforts has never been greater (Green, 2009).

It has been estimated that less than 10 percent of all current aquaculture production can be attributed to improvement in stocks (Gjedrem et al., 2012). Hence, aquaculture is far behind other animal genetic breeding programs. Genetic selection will generally have an end product of increased production and increased efficiency relative to the amount of feed, reduction in space needed, and the amount of labor required. The potential for high gains in growth in aquatic species has been well documented, but breeding programs remain quite limited. For example, research efforts with European seabass have recently been directed toward selection for high growth rates on diets containing plant-based rather than feedstuffs of fish origin (Le Boucher et al., 2013). Efficiency of use of resources must be the ultimate determining factor in breeding programs, such that breeding for higher production must be weighed against a prioritized array of values. Olesen et al. (2000) argued that in the quest for sustainable production systems, breeding goals include consideration of environmental and social concerns, such that market and nonmarket trait values should be dually examined. Combining marker-assisted selection with classic selection programs will speed up the process of producing those stocks that would have a positive impact on aquaculture production relative to meeting the protein consumption needs of the world. The use of genetic markers (i.e., transgenic fish) has not been positively received by the public, and a strong and sustained educational effort must be made to remove misconceptions of consequences of use of these fish for aquaculture enterprise.

Major advances in genetic editing technologies have been made possible with the development of the TALEs (transcription activator-like effectors) and CRISPRs (clustered, regularly interspaced, short palindromic repeats). These emerging technologies are promising tools for precise targeting of genes for agricultural and biomedical applications (Montague et al., 2014; Tan et al., 2013). In the future, there should be a focused effort on the factors that contribute to faster genetic gain across all species, which include: (1) a greater accuracy of predicted genetic merit for young animals; (2) a shorter generation interval; and (3) an increased intensity of selection because breeders can use genomic testing to screen a larger group of potentially elite animals (Schefers and Weigel, 2012). Genomic breeding strategies and transgenic approaches for making farm animals more feed efficient will be needed (Niemann et al., 2011). It is anticipated that genetically modified animals will play an important role in shaping the future of feed-efficient and thus sustainable animal production.

3-3.1 Advancements in Reproduction and Transgenesis

The earliest biotechnology procedure used to improve the reproduction and genetics of food animals was artificial insemination (AI), followed by embryo transfer and in vitro fertilization (Hernandez Gifford and Gifford, 2013). With the advent of AI came the opportunity to devise ways to control the estrous cycle for timed AI (Moore and Thatcher, 2006). More recent tools include super ovulation, in vitro production of embryos, cloning, sexed semen, and transgenics (Moore and Thatcher, 2006; Hernandez Gifford and Gifford, 2013). The benefit of cloning is in the increased accuracy in evaluation of bull dams and the acceleration of the rate of genetic progress. In addition, cloning provides a tool for the producer to propagate highly efficient and productive animals that require fewer inputs and a more positive environmental footprint. The transfer of new genetic material into animals via recombinant DNA protocols results in a transgenic animal. This technology has been available for over two decades and has numerous applications in food animal production including the potential to improve productivity, carcass composition, growth rate, milk production, disease resistance, enhanced fertility, and production of animals with reduced environmental impact (Table 3-2; Hernandez Gifford and Gifford, 2013). Despite its potential, the adoption of cloning and transgenics in animals for food use has not occurred because of societal concerns.

TABLE 3-2

Examples of Successful Transgenic Food Animals for Agricultural Production.

Artificial insemination is an example of a technology that was rejected or approached with much hesitation when first introduced and yet became a conventional breeding system in food animals, including specific lines of poultry production. During the last four decades, research has improved the collection and screening process for specific diseases, storage, and delivery of semen to females. This improvement has made the application of artificial insemination a practical and efficient way for breeding across the world with several food animal species. The improvement, in conjunction with several advancements in the research of embryology, including in vitro maturation, fertilization, and culture, has led to efficiency gains in the embryo transfer of food animal species. Embryo transfer is currently considered a way to improve breeding and avoid inbreeding issues that can affect production and cause diseases to spread. Embryo transfer in animals pioneered the application of this procedure in humans. Research finding recommendations applied to breeding procedures in specific food animal species, including sexed semen, cloning, and gene transfer, have contributed to food production efficiency and protein conversion. Looking ahead, application of reproductive biotechnologies such as cloning and transgenic animals needs to be considered as ways to more rapidly affect genetic change to produce the next generation of superior animals that will benefit the environment, producers, and consumers (Hernandez Gifford and Gifford, 2013).

Control of avian influenza by genetic modification benefits the poultry industry as well as the consumer. Lyall et al. (2011) demonstrated suppression of avian influenza transmission in genetically modified chickens in which transgenes were introduced without affecting other genetic properties of the bird. Research and education efforts should focus on understanding the barriers to consumer acceptance of such technologies to realize their full sustainability potential. Other areas for research utilizing reproductive technologies include improved semen technologies and cryopreservation (Rodríguez-Martínez and Peña Vega, 2013), improved fertility (Niemann et al., 2011), and development of technologies that will result in greater success for early pregnancy (Spencer, 2013). Early pregnancy translates into higher production and greater economic efficiency and sustainability of food animal production enterprises. Systems approaches that address nutrition, disease mitigation and prevention, environmental effects, and better adaptation through genetic selection will be important.

Recommendation 3-3

Further development and adoption of breeding technologies and genetics, which have been the major contributors to past increases in animal productivity, efficiency, product quality, environmental, and economic advancements, are needed to meet future demand.

Research should be conducted to understand societal concerns regarding the adoption of these technologies and the most effective methods to respectfully engage and communicate with the public.

Other Research Priorities

Reproductive technologies, such as artificial insemination and embryo transfer, continue to result in more rapid genetic improvement, especially in ruminants. In addition, epigenetics, which is the study of the impact of relatively subtle alterations of the genetic code through such processes as methylation of DNA bases, is an exciting new research area that shows promise of providing insights into factors related to post-embryo processes that affect animal growth and health. Improved understanding of genetic x environment interactions can further our understanding of production efficiency while considering other aspects of sustainability such as animal welfare. Research priorities for this area include:

• Research in understanding gene–environment interactions, epigenetics, genomics, nutrigenomics, for example, using biotechnological tools and genetic editing should be conducted to meet the goal of production efficiency while also considering other meaningful components of sustainability such as animal welfare.
• Research leading to advances in the integration of genomic and phenotypic information, genomic breeding strategies, obtaining faster genetic gain, greater accuracy of predicted genetic merit, shorter generation intervals, and increased intensity of selection should continue, particularly in aquaculture.
• Resources should be devoted to the new field of epigenetics, with its potential to provide insight into predicting and integrating the effects of multiple growth promoters and stressors into animal agriculture.
• Animal science departments should integrate computational biology and bioinformatics expertise into traditional animal science disciplines in order to capitalize on the potential of genomics, epigenetics, and metagenomics to improve animal husbandry, productivity, and sustainability.
• Reproductive technologies, such as embryo transfer and cryopreservation, should be further developed and utilized to accelerate the rate of genetic gain. Further emphasis is needed on semen characterization, storage, and quality.

Recommendation 3-4

The committee notes that understanding the nutritional requirements of the genetically or ontogenetically changing animal is crucial for optimal productivity, efficiency, and health. Research devoted to an understanding of amino acid, energy, fiber, mineral, and vitamin nutrition has led to technological innovations such as production of individual amino acids to help provide a diet that more closely resembles the animal's requirements, resulting in improved efficiency, animal health, and environmental gains, as well as lower costs; however, much more can be realized with additional knowledge gained from research.

Research should continue to develop a better understanding of nutrient metabolism and utilization in the animal and the effects of those nutrients on gene expression. A systems-based holistic approach needs to be utilized that involves ingredient preparation, understanding of ingredient digestion, nutrient metabolism and utilization through the body, hormonal controls, and regulators of nutrient utilization. Of particular importance is basic and applied research in keeping the knowledge of nutrient requirements of animals current.

Other Research Priorities

Organic animal agriculture is growing in the United States. For example, organic livestock increased from ~56,000 head in 2000 to ~492,000 in 2011, and poultry numbers have steadily increased from 3.1 million to 37 million. Although in certain circumstances organic animal agriculture can contribute to sustainability at the local level, such as by decreasing energy needs for transportation and by lessening the concentration of waste in a single location, there is no evidence to suggest that organic animal agriculture in its present form can be scaled up to make a substantial contribution to current or future needs for animal protein. Research priorities for this area include:

• For organic agriculture to contribute significantly to meeting global protein demand, research directed toward quantifying the potential for organic agriculture to be sustainably scaled up (equal or better environmental footprint per unit of animal protein produced, equal to or more affordable supply of animal protein, equal to or greater efficiency in animal protein production compared to conventional) to meet more than local needs is essential.
• Very high priority should be given to research into how best to enhance informed and respectful engagement between the scientific community and the public on issues related to the potential role of organic agriculture in achieving sustainable local and global impacts on food security.

3-5.1 Agricultural Animal Models Benefiting Animals

Research using animal models together with characterized diets has been beneficial in advancing animal nutrition and has contributed to what is known about nutrient–nutrient interactions, bioavailability of nutrients and nutrient precursors, and tolerance levels for excessive intakes of nutrients (Baker, 2008). In the last 50 years, efforts were made to understand the biology of animals and poultry in quantitative terms. Baldwin and Sainz (1995) and Dumas et al. (2008) provide a historical perspective to the mathematical models used in animal nutrition as well as a discussion on the mechanistic dynamic growth and lactation models. Many of these mathematical models with sensitivity analyses helped animal science researchers to focus on areas where knowledge gaps needed to be filled and to have major impacts on the biological system as a whole. Other animal models were developed to accurately predict nutrient requirements of animals in different stages of development, including maintenance, growth, lactation, and reproduction. Energy and protein feeding systems exemplified in the NRC nutrient requirement publications describe the nutrient requirements of more than 20 species of domestic animals and have evolved considerably over the past 40 years. Although systems have remained static, factorial, and largely empirical in nature, mechanistic concepts have been incorporated into the statistical models used in analyses of input-output data and applied in the revised systems (Baldwin and Sainz, 1995). The NRC nutrient requirement publications in the last 15 years for dairy, beef cattle, and swine all contain animal models that use environmental, management, and feed inputs to predict animal requirements and performance. In the future, agricultural animal models will need to become more dynamic and mechanistic, and more integrated into biological systems to reflect and accurately predict whole-animal performance for both research and field applications. They will also need to include consequences for and from environmental change, especially regarding performance as it relates to biogeochemical cycling and climate change. Although the committee believes that comprehensive system models that include soil, crop, animal, land use, for example, would be useful in studying such environmental tradeoffs, the scope of the work focused on animal science research and thus animal models is specifically highlighted in this section. McNamara and Shields (2013) and Lantier (2014) suggest that animal models be used as tools for understanding emerging or reemerging infectious diseases. Biomathematical system models will be needed for integrating nutrition, growth, reproduction, and lactation to predict animal performance. Such models will enhance animal science research in exploring and predicting the effects of different feeds, feeding systems, management, environment, and health.

3-5.2 Agricultural Animal Models Benefiting Humans

Agricultural animal models have been used in biomedical research to study a wide range of physiological and disease factors important to humans (Ireland et al., 2008). Seventeen Nobel Prize winners have used farm animals such as cattle, pigs, sheep, goats, horses, and chickens as research models (Roberts et al., 2009), yet their value is generally underappreciated. “There are numerous examples of compelling domestic species models relevant to diverse areas of biomedical research, including comparative physiology and genomics, cloning, artificial insemination, ‘biopharming’ to produce high-value pharmaceuticals in milk, osteoporosis, diabetes-induced accelerated atherosclerosis, asthma, sepsis, alcoholism, and melanoma” (Roberts et al., 2009). Agricultural animals should continue to be used in biomedical research.

Research Priorities

Mathematical animal model systems have been helpful in identifying key areas to research as well as providing a better understanding of the function of biological systems and predicting nutrient requirements and performance. They have also been helpful as models for studying physiological processes and diseases that may have important implications for other animals and humans. Such efforts also are critical to improving our understanding of complex biogeochemical cycling affecting climate and environment, including geographical variability. Research priorities for this area include:

Funding of research to encourage the development of animal models that are more dynamic, mechanistic, with more comprehensive integrated biological systems (i.e., growth, maintenance, reproduction, lactation) is needed to accurately predict whole-animal performance for and provide better assessments of current and potential future practices in animal agriculture.

Funding agencies should increase their emphasis on biomathematical modeling systems research at all levels (e.g., tissue, whole-animal, and production systems levels) and building and strengthening connections between modelers and experimental animal scientists.

3-6 Feed Technology and Processing

Feed technology and processing are important in enhancing productive efficiency and production in food animals. Particle size is important in rate and extent of digestion. Particle size of the diet can be too small and cause health problems such as stomach ulcers in pigs and acidosis in cattle, or too large in size and cause decreased digestibility and reduced feed intake. Heating has become important in deactivating antinutrients in feeds such as soybeans, enhancing starch digestibility through gelatinization in the steam flaking of corn and milo, and pelleting and extrusion processes; however, too much heat can be detrimental to certain amino acids, vitamins, for example (Institute for Food Technology, 2010). Feed processing is important in dust control and achieving higher feed intakes, maintaining a uniform composition, and reducing waste. Feed technology is important in aquaculture to deliver a floating, slowly sinking or sinking feed depending on the feeding behavior of the intended species. Better methods are needed to deliver dietary nutrients that are acceptable to the animal as well as contain the required nutrient density without suffering quality. This has involved grinding, pelleting, extrusion, and coating technologies as well as others. In ruminants, processing of forages and delivering feeds as total mixed rations, which reduces the animal's ability to sort out feed ingredients so that each mouthful contains the same consistent nutrient profile, has proven to improve production by reducing the variability of nutrient intake.

For a review of issues and challenges in feed technology pertaining to particle size, pelleting, and feed uniformity, see Behnke (1996) and Neves et al. (2014) and for a review on heat treatment and extrusion in animal feeds, see the proceedings of the 2nd Workshop, “Extrusion Technology in Feed and Food Processing” (Institute for Food Technology, 2010).

Research Priorities

Feed technology and processing is important to improving feed acceptability to the animal, feed efficiency, and animal health, and reducing feed wastage. One research priority in this area includes:

• Research in feed technology and processing should continue to make further step changes in the most efficient utilization of current and alternative ingredients in animals with minimal wastage (e.g., research areas of potential significance include improvements in water stability for aquaculture, enzyme stability in pelleting feed).

3-6.1 Alternative Feedstuffs

The feed industry and food animal producers are constantly looking for alternative feed ingredients that are more economical but maintain the right digestible nutrient profile, no contaminants, and compatibility with other currently used ingredients, and are organoleptically acceptable to the animal. Typically, co-products produced in making human food are used and include bakery byproducts, wheat midds, wheat bran, corn gluten feed, corn gluten meal, brewers' grains, fish meal, meat and bone meal, poultry byproducts, peanut meals, peanut hulls, rice mill byproduct, rice hulls, soybean meal, canola meal, almond hulls, citrus pulp, sugar beet pulp, sugar cane molasses, yeast, animal fat, whey, and blood meal. Other co-products are produced in nonfood industries such as biofuels (wet or dried distillers' grains, glycerin), cotton production (cottonseed meal, cottonseed hulls), fermentation waste products, and algae. Feed ingredients that do not compete with human food sources and can be converted to value-added nutritious animal products contribute to food security and are more favorable in terms of carbon footprint and environment.

Fish meal and fish oil, for example, are the main protein and oil sources used in the formulation of aquaculture diets, especially for carnivorous fish such as salmon. In 2007, principally in response to the use of unsustainable ingredients (feedstuffs) such as fish meal and fish oil in feeds for aquaculture, NOAA and USDA initiated the study of alternative feedstuffs and feeds for aquaculture. There is a finite supply of fish meal and fish oil, and with increased demand for salmon, alternative less expensive protein and oil sources are being advocated and evaluated (Naylor et al., 2009). Soybean meal can partially replace fish meal, and rapeseed oil can partially replace fish oil. However, there are limitations because alternative ingredients do not have the correct nutrient profile to provide 100 percent replacement of currently used feeds. For example, fish oil contains high levels of long-chain polyunsaturated fatty acids (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) that vegetable oils do not have. Thus, a minimum amount of fish oil must remain in the diet or an alternative source of EPA and DHA needs to be provided. Recently, insect meal has been being evaluated as a protein source. Use of insect meal derived from the larvae of insects feeding on seafood waste is an attractive area of future research (van Huis et al., 2013). Research has been devoted to an evaluation of the use of fish offal (processing waste) for the mass culture of insects that in turn can be prepared as a meal for use as an ingredient in formulated feeds. This is a promising area of research that offers the potential impact of ultimately eliminating the dependence on fish meal and fish oil as ingredients in feeds for carnivorous species. The insect meal would serve as a good source of amino acids and fatty acids that characterize fish meal and fish oil. For rainbow trout, Oncorhynchus mykiss, soldier fly prepupae served as an effective substitute for 25 percent of fish meal and 38 percent of fish oil ingredients. These larvae can be grown on fish offal (waste), and noteworthy increases in total tissue lipid (30 percent) and n-3 polyunsaturated fatty acids (3 percent) were observed in just 24 hours when compared to tissue of larvae that were fed on manure for an equivalent period of time (St. Hilaire et al., 2007).

Continued efforts need to be directed toward the use of mixtures of processed animal protein ingredients and plant-derived meals as partial or complete substitutes. Cost and benefits of these alternative feedstuffs can only be assessed through an understanding of the content and availability of nutrients in the feedstuffs, as well as the environmental footprint associated with their preparation and production. Research in improving the nutrient capture from co-products by livestock, poultry, and aquaculture is critically needed, especially the improvement in nutrient utilization of fiber by poultry, swine, and aquaculture. Research should also be directed to the development of technology of mass culture of microorganisms (e.g., algae, yeasts) using food or industrial waste streams as the substrate, and to the use of oilseeds that contain important required nutrients such as long-chain polyunsaturated fatty acids that are found in fish meal and fish oil and can potentially serve as ingredients of formulated feed (Byrne, 2014). Wastes (e.g., protein and oils) derived from the production of biofuels and byproducts from the processing of terrestrial animals also hold potential as alternative feedstuffs. Typically, the industry that is generating the new product funds the animal science research needed to commercialize the product. For example, Texas A&M AgriLife is evaluating algal residue for animal feed after the biofuel has been extracted (Texas A&M University, 2012). The environmental impacts of producing an alternative feedstuff will also need to be assessed (NOAA and USDA, 2011).

Recommendation 3-6.1

Potential waste products from the production of human food, biofuel, or industrial production streams can and are being converted to economical, high-value animal protein products. Alternative feed ingredients are important in completely or partially replacing high-value and unsustainable ingredients, particularly fish meal and fish oil, or ingredients that may otherwise compete directly with human consumption.

Research should continue to identify alternative feed ingredients that are inedible to humans and will notably reduce the cost of animal protein production while improving the environmental footprint. These investigations should include assessment of the possible impact of changes in the protein product on the health of the animal and the eventual human consumer, as well as the environment.

3-6.2 Feed Additives, Growth Promotants, and Milk Production Enhancers

Feed additives and growth promotants are used to enhance productivity and improve feed efficiency, often resulting in decreased environmental impacts per unit of output (Capper and Hayes, 2012). In the U.S. National Organic Program for animal production, use of most of these additives and growth promotants is not allowed. Feed additives may improve feed intake, alter the gut microbiome in a positive way, enhance nutrient absorption, decrease antinutritives, increase digestibility of fiber, improve mineral utilization such as phytate phosphorus, improve carbohydrate metabolism, decrease methane production and improve health. Examples of feed additives include exogenous enzymes, yeast, ionophores, organic acids, probiotics, and prebiotics. Ionophores, such as monensin, lasalocid, lailomycin, salinomycin, and narsin are rumen modifiers that improve feed efficiency while potentially reducing methane emissions in ruminants (Appuhamy et al., 2013).

Another area of feed-based research that has the potential of increasing production efficiency of aquaculture organisms is the use of probiotics and prebiotics in feeds. These live microbial or nondigestible compounds, such as oligosaccharides, are feed additives that have shown promise by increasing feed efficiency and/or immune response or resistance to pathogenic infection (NRC, 2011). Both additives have been shown to alter the resident bacteria within the gastrointestinal tract of fish and crustacean species. Although there are limited reports about the benefits of probiotics and prebiotics in aquaculture organisms, future efforts to increase production efficiency from their use are expected. Laboratory research that identifies positive responses to probiotics and prebiotics ideally should be complemented by testing under production settings.

Exogenous enzymes have improved the digestibility of feedstuffs and reduced waste (Meale et al., 2014). There is a need for a better understanding of the enzymatic machinery involved in cell-wall degradation through a better understanding of the microbial microbiome. The use of dietary enzymes as a means to increase the availability of nutrients to fish and crustacean species has had limited application, but experimental results have shown positive effects on the digestibility of protein and carbohydrates (Buchanan et al., 1997; Glencross et al., 2003). The lack of stability of these enzymes when exposed to high temperature as part of the aquafeed manufacturing process is still a challenge (NRC, 2011). A dietary supplement of phytase to increase the digestibility of phytic acid, a source of phosphorus contained in plant feedstuffs, has been successful in releasing phosphorus for uptake (Gatlin and Li, 2008). This procedure also has a positive environmental effect because less undigested phosphorus is then released into the environment as a potential pollutant. Biotechnological advances are needed whereby enzymes can be added to diets without surrendering their specific metabolic capabilities.

Food and Drug Administration–approved growth promoters and milk production enhancers have been key technologies resulting in improved production efficiencies in the U.S. cattle industry for over 50 years (Table 3-3). For example, researchers recently reviewed the results of 26 peer-reviewed journals or reviews by regulatory agencies on the efficacy and safety of sometribove zinc suspension (rbST-Zn), a form of recombinant bovine somatotropin, in lactating dairy cows (St-Pierre et al., 2014). The results of the meta-analysis indicated that rbST-Zn administration to dairy cows effectively increases milk production with no adverse effects on cow health and well-being. The findings are consistent with anecdotal reports regarding the use of recombinant bovine somatotropin in more than 35 million U.S. dairy cows over 20 years (St-Pierre et al., 2014). The development through research, adoption, and application of these feed additives, growth promotants, and milk production enhancers has contributed to food security and sustainability in several ways: (1) production costs have been reduced through reductions in the amount of feed required per unit gain; (2) the land necessary to produce equivalent amounts of food for consumers has been reduced; (3) the production of GHGs has been limited by reducing the number of animals required to produce equivalent amounts of beef or milk; and (4) cost savings have been extended to consumers by providing a year-round affordable supply of beef and milk at reduced prices (Johnson et al., 2013).

TABLE 3-3

Chronological Sequence of FDA Approval of Growth and Lactation Promotants Used in the U.S. Beef and Dairy Cattle Industries.

Research Priorities

FDA-approved feed additives, growth promoters, and enhancers of milk production have been successfully used for decades, resulting in improved efficiency and economics and reduced environmental footprint. In aquaculture production systems, for example, feed additives called prebiotics or probiotics have shown promise for increasing growth/feed efficiency and/or immune response or resistance to pathogenic infection. Research priorities for this area include:

The committee supports the initiation and/or the continuation of research devoted to the development of products that enhance growth and lactation of animals.

Research needs to be conducted to identify prebiotics and probiotics that have documented efficacy in the improvement of growth and immunocompetence.

Social science research needs to be conducted to understand the social ramifications and public concerns about the use of these technologies in the production of animal protein and how to better engage and respectfully communicate the substance of the technology and its benefits and risks to the public, to food security, and to a sustainable environment.

Recommendation 3-7

The subtherapeutic use of medically important antibiotics in animal production is being phased out and may be eliminated in the United States. This potential elimination of subtherapeutic use of medically important antibiotics presents a major challenge.

There is a need to explore alternatives to the use of medically important subtherapeutic antibiotics while providing the same or greater benefits in improved feed efficiency, disease prevention, and overall animal health.

Research Priorities

Animals must be healthy to achieve optimum production and efficiency. Animal diseases can result in market and trade interruptions, thus impacting food security, and may pose a significant human health threat. Advancements in animal health such as through vaccines and other preventive measures have resulted in less human labor, so that producers can handle a greater number of animals at improved efficiencies, increasing output per animal as well as per farm. Development of vaccines, however, is often frustrated by a limited knowledge of immune systems. Development must include cost analyses relative to production, delivery, and effectiveness, with particular emphasis on the development of successful vaccines using live viruses. Research priorities for this area include:

Funding agencies should support research to address the entire production system's specific production loss due to disease. The research should integrate various components in the production system and not restrict it to animal health aspects. An example is PED virus, for which production, animal movement, and feed ingredients must be considered (see Box 2-1).

Scientific, husbandry, and educational tools and practices to enhance identification of and rapid response to an animal disease outbreak must be a focus of public-sector research. Continuing research is needed on technological tools, including biological models that can rapidly identify diseases, defects, or contamination in animal products.

Research should continue to achieve an understanding of the innate immune response of species, include aquatic species, leading to the identification of stimulants that will promote immunocompetence and the rapid development and production of efficacious vaccines or other preventive measures.

Research should be conducted to address threats of new and emerging zoonotic diseases that may be exacerbated by climate change and intensification (e.g., tickborne diseases).

Recommendation 3-8

Rising concern about animal welfare is a force shaping the future direction of animal agriculture production. Animal welfare research, underemphasized in the United States compared to Europe, has become a high-priority topic. Research capacity in the United States is not commensurate with respect to the level of stakeholder interest in this topic.

There is a need to build capacity and direct funding toward the high-priority animal welfare research areas identified by the committee. This research should be focused on current and emerging housing systems and management and production practices for food animals in the United States. The Foundation for Food and Agricultural Research, USDA AFRI, and USDA ARS should carry out an animal welfare research prioritization process that incorporates relevant stakeholders and focuses on identifying key commodity-specific, system-specific and basic research needs, as well as mechanisms for building capacity for this area of research.

Research Priorities

As an importer and exporter of animal protein products, the United States is affected by the development of international standards, guidelines, and recommendations that protect the health of the farmed species and the consumers through regulation of contaminants in feeds and feedstuffs. One research priority for this area includes:

• Research through U.S. agencies in the identification of feed and feedstuff contaminants should continue so that rigorous policies of regulation can continue to be updated to protect the health of farmed species and consumers and provide information to feed manufacturers through outreach programs.

3-10.1 Food Technology

Supplying affordable, safe, and desirable animal products as a source of nutrients to the human diet is important. Americans annually purchase about $100 billion of animal products (e.g., meat and meat products, poultry products, fish, shellfish, and dairy products, and nonfood products, such as wool, mohair, cashmere, and leather) at the farm gate and retail levels (USDA NIFA, 2009). The quality and safety of animal products prior to harvest are influenced by genetics, nutrition, and management systems, while after harvest they are affected by handling, processing, storage, and marketing practices (USDA NIFA, 2009). The threat from foodborne illness due to animal products has been reduced during the last few decades, particularly because of the improvement in the hygienic process of food (Morris, 2011). The hygienic process of animal origin food was mainly derived through a series of recommendations from several research initiatives conducted via experimental and observational studies of foodborne agents (e.g., bacterial, viral, and toxins). The practice of Hazard Analysis of Critical Control Points (HACCP) was initiated through research and is currently becoming the standard for food safety in the United States and abroad as many food-producing systems are adapting HACCP in their operations. One obstacle in overcoming foodborne illnesses is public fear and resistance to food safety techniques such as meat irradiation (Box 3-11).

BOX 3-11

Irradiating Meat to Combat Foodborne Illness. The Centers for Disease Control (CDC) estimates that one in six Americans (or 48 million people) become sick from foodborne illnesses each year (CDC, 2014). Developing an effective means of ensuring that meat (more...)

A major goal of food safety is to determine a way to measure the impact of interventions at different phases of the production chain. Research is needed to examine individual interventions and those used in combination, and the economic considerations of such interventions. The continued identification and evaluation of risk factors is needed to understand the transmission and persistence of foodborne organisms, and the development and implementation of interventions, mitigation, prevention, and/or control strategies are needed (Oliver et al., 2009). Research should target more rapid, sensitive, and specific diagnostic tests for many foodborne pathogens.

With the growing popularity of “organic” and “natural” food products and the number of recalls of products from these production systems, an increased emphasis on food safety is required, especially in microbial pathogen control. Research is needed to determine better and faster pathogen detection methods for laboratory and field application (Sofos, 2009). The concept of food quality has been evolving within the animal product industry to where there is (1) hygienic quality (i.e., absence of heavy metals, pesticides, mycotoxins, feed additives, drugs, pathogens, and microbial contaminants); (2) compositional quality (e.g., water, protein, fat, and ash); (3) nutritional quality (i.e., biological value of protein and fatty acid composition); (4) sensorial quality (e.g., taste, color, flavor, odor, tenderness, and juiciness); and (5) technological quality (i.e., suitability for processing, storage, and distribution) (Nardone and Valfrè, 1999). Hocquette et al. (2005) provided other definitions of quality; however, most experts make a distinction between intrinsic and extrinsic quality attributes. Intrinsic quality refers to safety and health aspects, sensory properties and shelf-life, chemical and nutritional attributes, and reliability and convenience of food. Extrinsic quality refers to production system characteristics and marketing variables such as traceability. The most important intrinsic quality traits include color, texture, flavor, juiciness, and healthiness, and the most important extrinsic trait is traceability (Hocquette et al., 2005). Traceability needs ongoing validation because it is a vital component of operational standards and certification programs. The implementation of traceability for aquaculture products is a work in progress that is confronted with many challenges (Schroder, 2008). Traceability systems are particularly pertinent to aquaculture products that are taking on increasing significance in global trade and are highly perishable. Product supply chains are monitored with the ultimate goal of guaranteeing an accurate determination of product sources to protect consumer health and prevent fraud (e.g., misrepresentation of species). A practical guide for traceability in the U.S. seafood industry has been produced (Petersen and Green, 2006).

There have been many advancements and innovations in animal product quality in the past 30 years (Aumaître, 1999; Nardone and Valfrè, 1999; Higgs, 2000; Hocquette et al., 2005, 2007; Goff and Griffiths, 2006; Henning et al., 2006; Sofos, 2009). Nardone and Valfrè (1999) evaluated the effects of production methods and systems such as genetics, nutrition, management, and animal health on poultry meat, cattle meat, eggs, and milk quality. Genetics provides the greatest opportunity for improvement in quality, followed by nutrition and management. An example of the application of functional genomics on beef quality such as tenderness and marbling is provided by Hocquette et al. (2007). Research has also determined how quality attributes such as color, texture, tenderness, flavor, and juiciness can be altered (Hocquette et al., 2005). In the dairy industry, fluid milk processing has made technological advancements in extending the shelf life of milk by high-heat treatment, microfiltration, and aseptic packaging (Goff and Griffiths, 2006). Membrane filtration technology has been an important advancement in dairy processing in the past few decades for all dairy products, and cheese production has benefited from increased knowledge of the genetics of microorganisms used during their production (Henning et al., 2006; Johnson and Lucey, 2006). Red meat production has benefited from selective animal breeding and the increased trimming of fat, which has resulted in a decrease in the total fat and saturated fat content of red meat (Higgs, 2000).

In the future, animal product research in the United States needs to focus on the quality of animal food products. Genomics and proteomics are likely to be the most important factors in affecting animal product quality (Nardone and Valfrè, 1999; Hocquette et al., 2005; Johnson and Lucey, 2006). Animal nutrition research needs to further assess the sanitary and nutritional characteristics of meat (i.e., fatty acid composition such as conjugated linoleic acid and omega-3s, polyunsaturated fatty acids, vitamins and trace minerals, antioxidants, and chemical and technological characteristics of fat). The effect of different management systems on meat, milk, and egg quality will need further research with a focus on hygienic and organoleptic qualities Fundamental research is important to understand the biological and physical mechanisms, and to develop new techniques to improve quality. Sensory quality and methods using a systems approach to improve the nutritional value of fish, meat, milk, and eggs and associated products should remain a research priority (Hocquette et al., 2005).

3-10.2 Food Losses and Food Waste

Food is lost or wasted throughout the food chain (Figure 3-4). Food losses refer to qualitative (i.e., reduced nutrient value, undesirable taste, texture, color, and smell) and quantitative (i.e., weight and volume) reductions in the amount and value of food. Food losses represent the unconsumed edible portion of food available for human consumption. Food waste is a subset of food loss and generally refers to the deliberate discarding of food because of human action or inaction.

FIGURE 3-4

Areas of food losses and wastage. Illustration by Britt-Louise Andersson, Stockholm International Water Institute. SOURCE: Lundqvist et al. (2008). Reprinted with permission from the Stockholm International Water Institute.

Food loss and waste are important for the following reasons (Buzby and Hyman, 2012): (1) food is needed to feed the growing population and those already in food insecure areas; (2) food waste represents a significant amount of money and resources; and (3) there are negative externalities (i.e., GHG emissions from cattle production, air pollution and soil erosion, and disposal of uneaten food) throughout the production of food that affect society and the environment. Annual global food loss and waste by quantity is estimated to be 30 percent of cereals; 40-50 percent of root crops, fruits, and vegetables; 20 percent of oilseed, meat, and dairy products; and 35 percent of fish (FAO, 2014a). One-third or 1.3 billion tons of the food produced for human consumption is lost or wasted globally (Gustavsson et al., 2011). In 2008, the estimated total value of food loss at the retail and consumer levels in the United States as purchased retail prices was $165.6 billion or 30 percent of the total value (Table 3-5; Buzby and Hyman, 2012). In terms of the value of food loss, meat, poultry, and fish accounted for 41 percent and dairy products for 14 percent of the total loss in food supply value (Buzby and Hyman, 2012).

TABLE 3-5

Estimated Total Value of Animal Product Loss at 2008 Retail and Consumer Levels in the United States.

The total food loss at the combined retail and consumer level in the United States was estimated to be 28 percent dairy products, 38 percent meat, 41 percent poultry, 33 percent fish and seafood, and 23 percent eggs (Buzby and Hyman, 2012). The major contributors to food loss at this level include spoilage, expired sell-by dates and confusion over label dates (NRDC, 2014), all of which pertain to shelf life. In the United Kingdom, 60.9 percent of the food wasted could be attributed to storage and management, which is directly linked to shelf life with smelling and tasting bad and past due dates as the major reasons for disposal (WRAP, 2008). One extra day of shelf life could result in savings of £2.2 billion due to less food waste in the United Kingdom (Robinson, 2014).

One major research focus for food loss in animal products is shelf life. Shelf life can be defined as the time it takes a food product to deteriorate to an unacceptable degree under specific storage, processing, and packaging conditions. Time to deteriorate depends on the product composition, storage conditions (e.g., temperature, atmosphere), processing conditions, distribution conditions, initial quality, and packaging. Modes of food deterioration include microbial, insects and rodents, chemical (i.e., oxidation, flavor deterioration, color change or loss, vitamin loss, enzymatic), and physical (i.e., moisture or textural change) (Hotchkiss, 2006). For aquaculture, technologies that can be effectively applied post-harvest are needed to extend shelf life. Improving animal product shelf life would reduce wastage and open or expand export markets, and may make niche-oriented, lower-volume products more economical.

A lot of research has gone into extending the shelf life of dairy products. Dejmek (2013) provides a historical overview of milk shelf life including heat treatment, pasteurization, ohmic heating, and microwave and ultrahigh-temperature (UHT) sterilization. Post-pasteurization shelf life is affected by contamination of milk by psychrotrophic bacteria, presence of heat-stable enzymes (e.g., proteases and lipases), or presence of thermoduric psychrotrophs (e.g., bacterial spores that survive pasteurization) (Tong, 2009). With pasteurization and good storage temperatures, a 17- to 21-day shelf life can be attained. For extended shelf life, ultrahigh-temperature processes are used to sterilize all milk contact surfaces and disinfect packaging to prevent environmental contamination at filling. Shelf life for UHT milk may last 30 to 90 days in refrigerated storage. Bacterial growth is usually not an issue, but physical and chemical changes due to heating and prolonged storage can be major contributors to food loss (Tong, 2009). Research has found that storing milk at low refrigerated temperatures will reduce the rate of these changes affecting milk quality. Nonthermal technologies are being evaluated, such as pulsed electric field, high-pressure processing, membrane filtration, controlled-atmosphere packaging, and natural microbial inhibitors.

Extending the shelf life of eggs is another area of investigation. Eggs cooled under current methods lose AA grade (highest grade for eggs) in 6 weeks. If eggs could maintain AA grade for 8 weeks, then they could be shipped anywhere in the world. Scientists at Purdue University have discovered a rapid cooling technology that provides 12 weeks of AA grade rating (Wallheimer, 2012). Research efforts continue in the extension of meat shelf life. Major contributors to meat waste include off-color in the retail case and rancidity caused by oxidation, microbial contamination, and microbial load. Consumers in the United States prefer red meat to be red in appearance. The red color is the result of myoglobin in the meat binding to oxygen and iron (ferrous form) and converting it into oxymyoglobin. Over time, the oxymyoglobin is converted to metmyoglobin, due to oxidation, resulting in the meat changing color to brown, which is unappealing to consumers. In an effort to extend the shelf life and keep the appearance of the meat red longer, cattle feeders can feed a high level of Vitamin E (antioxidant) to animals. The Vitamin E deposited in the muscle tissue by the animal results in an antioxidant effect, thereby slowing the color change in meat. Currently, cattle producers have not widely adopted the practice because the economic benefit to the retailer has not been passed back to the producers who must increase production costs to use Vitamin E.

Microbial load on or in meat can reduce shelf life and potentially cause human safety concerns, resulting in massive recalls and waste. Irradiation technology was developed to mitigate this problem. Pasteurization technologies such as irradiation, freezing, flash pasteurization, and ultrahigh-pressure exposure have been successfully used to inactivate pathogenic enteric viruses such as Vibrio in mollusks (Richards et al., 2010). New products and concepts to address the microbial load and contamination, including edible antimicrobial films being placed on the surface of meats to extend shelf life, are being explored (Morsy et al., 2014). Packaging technologies are also being researched to help extend meat shelf life. The goal of packaging is to reduce the rate of quality loss and extend shelf life. Recent technologies to extend shelf life include modified-atmosphere packaging (MAP), vacuum-skin containers, higher-barrier packaging, direct addition of carbon dioxide to products, broader use of irradiation, high pressure, ohmic heating, and pulsed-light treatment (Hotchkiss, 2006; Spinner, 2014). MAP is a packaging technology advancement that includes directly adding carbon dioxide (CO2 pad technology) to the package to displace oxygen and ethylene, which prevents the growth of aerobic bacteria. In February 2011, FDA granted approval for a CO2 pad technology to be used for meat, poultry, seafood, and fruit and vegetables, which is now in commercial use (JS Food Brokers, 2014). In addition, antimicrobial packaging is being investigated where the packaging material contains antimicrobial or bioactive materials, selective and adjusting barriers, indicating and sensing materials, and/or flavor-maintenance and -enhancing materials (Hotchkiss, 2006).

Research efforts need to continue to reduce animal product waste in the United States. Dejmek (2013) outlined the following areas to be further explored for dairy products: (1) sterile extraction of milk and the maintenance of carbon dioxide/oxygen status of raw milk; (2) a more complete understanding of the biology of spore germination, which would lead to new methods of reliably inducing germination and thus removing the need for sporicidal treatments; (3) affinity-based separations of pathogens and product spoiling enzymes; (4) a better understanding of the casein micelle to make it possible to manipulate the micelle size on the technical scale and thereby improve the efficiency of bacteria separating methods; and (5) improvement of centrifugation efficiency by detailed computational fluid dynamics simulations of centrifuge flow patterns, which are now feasible. Research to extend fish, meat, milk, and egg shelf life and mitigate and prevent microbial contamination at the point of animal product harvest and packaging should be pursued. Research is also needed into how to better communicate the benefits and safety of technologies such as irradiation, which have been met in the past by consumer resistance.

3-11.1 Implications of Historical U.S. Animal Agricultural Trends

In many cases, the changes in production efficiency that have been made across species in animal agriculture as previously discussed translate into reduced environmental emissions and resource use per unit of output (Table 3-6). Increased daily body-weight gains, daily milk yields, reproductive performance (e.g., eggs/hen per year), and shortened times to slaughter have all had a net effect of decreasing the amount of resources required for animal maintenance relative to animal production on an individual animal and a herd/flock basis (Capper and Bauman, 2013).

TABLE 3-6

Published Historical Comparisons of U.S. Egg, Dairy, and Beef Industries' Environmental Impacts and Resource Use.

Concomitantly with increased production efficiency, there has also been tremendous intensification and geographical concentration of U.S. terrestrial animal operations over the last several decades. Across all major U.S. animal agricultural industries, there has been a consistent trend toward decreasing the number of operations and increasing animal numbers per operation; however, total U.S. animal populations for the ruminant industries have greatly declined from historic highs (Figure 3-5).

FIGURE 3-5

Distribution of 21.9 million dairy cows and heifers in 1939 (Top) and distribution of 9.3 million dairy cows in 2012 (Bottom). SOURCES: USDA ESMIS (2012); USDA Census of Agriculture (2012a).

The concentration and confinement of animals in one geographical location have increased public concern about how nutrients (particularly manure nutrients) are managed and lost to the environment and about human and animal health and welfare (Fraser et al., 2001; Donham et al., 2007). One notable exception to the concentration trend is the cow-calf and stocker/backgrounder phases of the U.S. beef industry. More cow-calf production now occurs from larger herds; however, there are still over 700,000 cow-calf producers in the United States with an average herd size of 40 beef cows (USDA Census of Agriculture, 2012b). Additionally, both of these phases of the beef production chain rely heavily on extensive grazing of pasture and rangeland; therefore, there are inherent limits to the degree of consolidation that can occur in these sectors when extensive production practices are used.

Although improvements in production efficiency have largely reduced environmental impacts and resource use across animal industries per unit of output in the United States, there are nutrient concentration or resource supply challenges that are affecting and are affected by animal production. One example is water use in the western United States. California is currently experiencing a severe drought, which is highlighting the challenges of allocating water to municipalities, agriculture, and ecosystems within the state (Howitt et al., 2014). Another example is the High Plains Aquifer (or Ogallala), which extends from western Texas and eastern New Mexico to South Dakota and has dropped precipitously in certain areas, especially in the aquifer's southern portion (USGS, 2014). The area's economy is highly dependent on agriculture, and the region produces significant amounts of dairy, beef, and pork. The long-term viability of those industries in their current state may be impossible if the drop in the aquifer continues at its current rate (Steward et al., 2013). Water for animal feedstuff production contributes to 98 percent of the water footprint of animal products (Hoekstra, 2012). Research into improved water use, improved cropping systems (e.g., using lower-water-use crops and cover cropping), and better understanding of the social components of water use in the region (e.g., public policy) will be critical for the continued existence of animal agriculture in the region.

Clearly, these challenges to resource use and allocation extend far beyond the traditional boundaries of animal science research; however, incorporation of other sciences into a transdisciplinary approach will be necessary to manage such sustainability challenges related to animal production. As a result of increasing public concern and environmental regulatory measures, the past few decades have resulted in an increased focus on research, extension, and education of the environmental management of terrestrial animal agriculture. Efforts have been focused primarily on the impacts of animal agriculture on water quality; however, there has been an increasing interest in the impacts of animal agriculture on air quality and climate change.

Research Priorities

Animal agriculture is a major consumer of surface and groundwater resources, with 98 percent of the water footprint of animal agriculture due to the production of feedstuffs for food animals. One research priority in this area includes:

• Research to increase the water-use efficiency of animal agricultural systems (including feed production) is necessary (e.g., better irrigation, water recycling, identifying animals that are more water-use efficient); however, such research should also consider the complicated issues of water resource allocation in areas of stressed freshwater availability.

3-11.2 Climate Change and Variability

Adaptation and building resilience to climate variability and change in animal agricultural systems will be a major challenge in the coming decades. Climate change will likely affect feed-grain production, availability, and price; pasture and forage crop production and quality; animal health, growth, and reproduction; and disease and pest distributions (Walthall et al., 2012). Increasing concentrations of carbon dioxide and certain impacts of climate change may also have beneficial implications for animal agriculture. Increasing atmospheric carbon dioxide concentrations may have a positive effect on the yields of plant species important for animal agriculture, particularly those with C3 photosynthetic pathways (e.g., wheat, barley, and soybeans; Wheeler and Reynolds, 2013). However, plants that use the C4 photosynthetic pathway have much less of a yield gain than C3 plants (Wheeler and Reynolds, 2013). For both C3 and C4 plants, water-use efficiency is improved in conditions of higher carbon dioxide concentration (Drake et al., 1997).

Benefits of increasing carbon dioxide concentration on plant growth may be mediated by other environmental changes due to climate change, such as soil water availability (Polley et al., 2013). Increased variability in temperatures and precipitation will likely lead to decreased feed quality and increased environmental and nutritional stress for some animal agricultural species (Craine et al., 2010; Nardone et al., 2010; Wheeler and Reynolds, 2013). For example, an investigation of 76 years of growth records for Hereford beef cattle in the Northern Great Plains revealed that calf growth was greater in longer, cooler growing seasons, suggesting that increased temperatures decrease calf growth in the region (MacNeil and Vermeire, 2012). Heat stress already has a significant impact on the dairy, beef, swine, and poultry industries in the United States, with estimated annual economic costs at $1.69 billion to $2.36 billion due to decreased growth, reproductive performance, and lactation performance (St-Pierre et al., 2003). The prospect of more frequent heatwaves and higher average temperatures in the coming decades emphasizes the need for creating animal agricultural systems that are more adaptable and resilient to increased thermal stress.

As with terrestrial animal agriculture, climate change and variability will likely have both positive and negative effects on aquaculture. The United States currently imports 85 percent of its fish and shellfish; therefore, the impacts of climate change in major aquaculture regions such as Southeast Asia can have a significant impact on the ability to sustainably meet U.S. demand (Hatfield et al., 2014). Adaption and mitigation of the detrimental effects will be in response to changes in sea level and sea temperatures. Increases in sea level will eliminate or require the movement of existing coastal ponds, and increases in sea temperature will also affect growth of species cultured in cages, possibly increasing the incidence of disease. Oceans are absorbing approximately 25 percent of the CO2 emitted into the atmosphere, which is reducing oceanic pH (acidification), and ultimately affecting the physiology of species such that their presence and/or productivity would be reduced (Walsh et al., 2014). Temperature changes in the water can affect the direction of currents and changes in the wind magnitude and direction. These changes may ultimately compel an adaptive response founded in the need to relocate offshore operations. The prospects of expansion of the aquaculture enterprise along the coasts of the marine environment will frustrate continued development. Policy decisions will have to be directed toward actions whereby mitigation and adaptation can be successfully implemented without compromising production. Because 65 percent of current aquaculture production is inland, mitigation activities for these freshwater production activities may be on a lower scale of magnitude than marine production activities (De Silva and Soto, 2009). One major concern is the lack of sufficient water resources; however, other concerns are water stratification in ponds or changes in disease-causing microbial flora.

Heffernan et al. (2012) offered the following recommendations to address the effects of climate change on animal infectious diseases. There is a need for frameworks and/or approaches that support collective learning and approaches within this emerging field. There is a need to enhance our abilities in predictive decision making. Critical areas that were identified as gaps include: (1) a greater understanding of the role of extra-climate factors on animal health, such as management issues and socioeconomic factors, and how these interplay with climate change impacts; (2) a greater cross-fertilization across topics/disciplines and methods within and between the field of animal health and allied subjects; (3) a stronger evidence base via the increased collection of empirical data in order to inform both scenario planning and future predictions regarding animal health and climate change; and (4) the need for new and improved methods to both elucidate uncertainty and explicate the direct and indirect causal relationships between climate change and animal infections.

Research will be needed to address the effects of climate change on crop productivity (Wheeler and Reynolds, 2013) and crop nutrient content. Bloom et al. (2014) reported a decrease of 8 percent in protein concentration in wheat, barley, rice, and potatoes with higher atmospheric carbon dioxide levels. Climate change effects on infectious diseases (Heffernan et al., 2012; Sundström et al., 2014) and animal production (Sundström et al., 2014) also need more research. Walthall et al. (2012) suggested research into technologies that improve management of agricultural products through automation of processes and tools, sensor development, and enhancement of information technologies.

The impacts of climate change and variability outlined above will have negative consequences for the efficiency of animal production and, thus, the environmental impact per unit of production. Consequently, adaptation to climate change and the mitigation of GHG emissions (and other environmental emissions) are intertwined, and future research should increase the understanding of the impact of animal agriculture on the environment and the impact of the environment on animal agriculture rather than researching these relationships in isolation.

3-11.3 Greenhouse Gas Emissions

In animal agricultural production, the GHGs that have received the most attention are nitrous oxide and methane. Carbon dioxide emissions result from the production of animal protein via the burning of fossil fuels throughout the supply chain and from soil in cropping systems. Respiratory carbon dioxide emissions from animals typically are not considered a net source of GHG emissions because the respiratory carbon dioxide is assumed to be offset by the carbon dioxide sequestered by the plants that animals consume (Steinfeld et al., 2006). Researchers, however, have evaluated GHG emissions from animal agricultural systems by accounting for carbon dioxide sequestered by plants and also respired by animals (Stackhouse-Lawson et al., 2012). Other GHG emissions from the production of animal protein include high-global-warming-potential refrigerants that can leak to the environment from the transportation and retail sectors of the supply chain (Thoma et al., 2013).

Nitrous oxide emissions from animal production typically result from soils applied with manure (i.e., deposited by grazing animals, deposited in open dry-lot facilities, or applied to pasture or cropland as a fertilizer source) or synthetic nitrogen fertilizers due to denitrification processes carried out by anaerobic bacteria (Robertson et al., 2013). Nitrous oxide emissions can also occur from manure storage systems, although total emissions from manure storage systems tend to be much lower than nitrous oxide emissions from manure-amended soils (EPA, 2014). This is due to the required nitrification transformation of manure ammonium to nitrate often being inhibited by the anaerobic nature of many manure storage systems in intensive U.S. animal operations (Montes et al., 2013). Although there is current and past research quantifying and investigating nitrous oxide emissions mitigation strategies, further collaborative efforts across crop and soil science, engineering and animal science disciplines will be needed to make significant improvements in emissions reductions. A particular emphasis should be placed on knowledge transfer of cost-effective mitigation strategies to animal agricultural producers. Furthermore, there is currently very little research on nitrous oxide emissions and mitigation opportunities in aquaculture systems, which is the fastest growing segment of animal agriculture; therefore, better understanding nitrous oxide emissions from aquaculture systems will be critical in coming decades (Hu et al., 2012).

Methane emissions can occur in anaerobic environments, such as manure storage systems and the foregut of ruminants. In 2012, enteric fermentation was estimated to account for 24.9 percent of U.S. methane emissions and 23 percent of GHG emissions from agriculture in CO2 equivalents (EPA, 2014). Emissions of methane from manure management were estimated to be 9.3 percent of total U.S. methane emissions and 8.6 percent of GHG emissions from agriculture (EPA, 2014). The vast majority of methane emissions from enteric fermentation result from ruminant species (e.g., cattle, goats, and sheep); methane emissions from the digestive tracts of nonruminant herbivores and omnivorous species (e.g., pigs, poultry, and horses) are relatively minor (Crutzen et al., 1986). Methane emissions from ruminants generally increase with increasing feed intake and are affected by the type of carbohydrate and lipid content of the diet, feed processing, feed additives, or other strategies that can alter rumen microbial populations (Johnson and Johnson, 1995). Under strict anaerobic conditions, prokaryotic archaea primarily reduce carbon dioxide with hydrogen gas to generate energy for their own life processes and, as a consequence, produce methane, most of which is eructated out of the ruminant animal's mouth (Ellis et al., 2008). Mitigation options for enteric methane emissions typically focus on inhibiting the archaea directly or reducing the amount of hydrogen gas available for methane production (i.e., methanogenesis). Mitigation options include the use of compounds that directly inhibit methanogenesis, alternative hydrogen gas sinks, ionophores, plant bioactive compounds, exogenous enzymes, direct-fed microbials, defaunation, manipulation of rumen archaea and bacteria, dietary lipids, forage quality, forage-to-concentrate ratio of the diet, feed processing, and precision feeding (Hristov et al., 2013). For many of the above-listed enteric methane emission techniques, more data from live animal experiments and long-term experiments are needed to determine their long-term efficacy (Hristov et al., 2013); however, collecting such data can be expensive due to the equipment and labor requirements involved. For U.S. ruminant systems, there is a dearth of data from grazing ruminant emissions because of the methodological challenges of measuring enteric methane emissions while allowing animals to graze. Additionally, increased consideration should be given to the cost-effectiveness of enteric methane mitigation strategies and the potential tradeoffs and unintended consequences of mitigating enteric methane emissions on other aspects of animal agricultural sustainability.

Methane from manure is typically emitted from liquid or slurry manure storage systems, with very little methane produced once manure is applied to land (Montes et al., 2013). Methane mitigation options from manure storage typically focus on either preventing anaerobic conditions in storage systems, or, if anaerobic conditions exist, capturing or transforming methane through a flare to oxidize methane to carbon dioxide (Montes et al., 2013). Recent developments in new manure management and treatment systems include anaerobic digestion, which has the potential to decrease odor and pathogen loads. Anaerobic digestion also reduces nitrous oxide emissions from the land application of digested manure and is a source of energy from the biogas produced (Holm-Nielsen et al., 2009; Montes et al., 2013). Currently, installing and operating anaerobic digestion systems on animal operations is fairly cost-prohibitive, which has limited its adoption by animal agricultural operations despite the potential to improve environmental sustainability. A recently released report, Climate Action Plan—Strategy to Reduce Methane Emissions (White House, 2014) highlighted the importance of manure management and treatment technologies, such as anaerobic digestion, in mitigating methane emissions and strengthening the nation's bioeconomy. Additionally, the report announced the partnership of the U.S. Environmental Protection Agency, Department of Energy, and USDA with the Innovation Center for U.S. Dairy to form a “Biogas Roadmap” to outline strategies to increase the adoption of anaerobic digesters. Furthering interdisciplinary research and engagement with stakeholders and policy makers is necessary to improve the economic viability of anaerobic digesters and increase their adoption.

Another incentive to develop cost-effective anaerobic digestive systems for animal agriculture is to “close the loop” and use food waste and other organic matter as feedstock for the anaerobic processes (Holm-Nielsen et al., 2009). With such systems, products previously considered waste with no human value and an environmental burden can be converted into valuable products and energy. Food waste at the retail, consumer, and food service portions of the animal agricultural supply chain are estimated to range from 16 percent of edible food for red meat, poultry, fish, and seafood to 32 percent of edible food for dairy products (Kantor et al., 1997). Waste-to-worth type of energy production systems can make animal production more sustainable and potentially avoid “food vs. fuel” dilemmas that occur with other biofuels, such as corn-derived ethanol.

Research Priorities

There are uncertainties associated with current GHG emission predictions; however, ruminant (cattle) meat production systems tend to have higher GHG emission intensities compared to monogastric (swine, poultry, fish) production systems. Dual-purpose ruminant systems (e.g., milk production) tend to have lower GHG emission intensities than ruminant meat production systems. GHG emission mitigation strategies can offer considerable synergies with other desirable outcomes (e.g., reducing methane emissions from ruminants can increase feed energy conversion efficiency, and anaerobic digestion of animal manure can lead to the generation of renewable energy). However, research testing GHG emissions mitigation strategies has often been conducted without consideration of economic and social sustainability concerns. Research priorities for this area include:

• Research investigating GHG emission mitigation strategies should consider the impacts of such mitigation strategies on other environmental pollutants (e.g., ammonia emissions), as well as the economic and social viability of such mitigation strategies. Whole farm systems and whole-food supply-chain systems-based evaluations of the effects of mitigation strategies are needed.
• Research should build on the potential value of anaerobic digestion of animal manure and other organic wastes as well as other approaches that help to close energy and nutrient loops in the food system.

3-11.4 Air Quality and Nuisance Issues

The concentration of animal production has shifted how animal manure and litter are managed. While animals in extensive systems will deposit their urine and feces while grazing or foraging, manure or litter in confinement systems must be collected and usually stored in some way. While anaerobically stored manure can be a source of methane emissions, fresh animal manure and litter in animal housing systems can be a source of ammonia emissions when applied to land. Ammonia emissions occur when manure is exposed to air and can be affected by pH, temperature, and wind speed (Robertson et al., 2013). Past research has investigated optimizing nitrogen use in animal diets, and improved manure management techniques that can reduce ammonia emissions. It has been estimated by the EPA (2014) that 54 percent of ammonia emissions come from animal waste. Emissions of ammonia from animal agricultural operations can contribute to human respiratory health problems, acidification of environments, and eutrophication of water bodies (Aneja et al., 2001; Pinder et al., 2007). Although these emissions are currently unregulated, U.S. regulation in the next 40 years is likely; therefore, further research, extension, and education efforts into increasing nitrogen-use efficiency and ammonia emission mitigation techniques from animal agricultural systems should be a priority to ensure science-based policy approaches and to provide viable mitigation options to animal agriculturalists.

Additionally, animal agriculture can contribute to the formation of tropospheric ozone through the emissions of volatile organic compounds and methane. Tropospheric ozone can both directly and through the formation of secondary aerosol particles lead to negative human health outcomes and decrease the net primary productivity of ecosystems and agricultural systems (Lippmann, 1991; Ainsworth et al., 2012; Shindell et al., 2012). Methane emissions from animal agriculture are typically not thought of as a local driver of ozone formation within airsheds, but rather contribute to the continued increase in global background tropospheric ozone concentrations (Fiore et al., 2002). As a consequence, research that identifies viable methane emission mitigation strategies can reduce animal agriculture's contributions to both climate change and reduced air quality. Recent research has found that most volatile organic compounds are emitted from fermented feed sources rather than fresh and stored manure sources (Howard et al., 2010a,b). Mitigation strategies that reduce emissions from fermented feed also have the potential to reduce feed losses, which is beneficial to animal agricultural producers (Place and Mitloehner, 2014). More research is needed to better characterize emission sources from animal agriculture that lead to reduced air quality, to develop economically viable mitigation strategies for animal agricultural producers, and to understand the relationships and tradeoffs of mitigation strategies with other aspects of sustainability.

Odor is a continual issue with animal agriculture in the United States, particularly in areas where suburban encroachment results in people previously unexposed to animal agriculture living in close proximity to animal farms. Research on characterizing and mitigating odor from animal operations has been ongoing for the past few decades; however, an improved understanding of the compounds that cause odor from animal operations and measurement technologies is required (Rappert and Müller, 2005). Additionally, pests, such as flies and rodents, can increase due to animal waste (e.g., feces and urine) and feedstuffs on animal operations, which can be another point of conflict with nonagricultural neighbors close to animal agricultural operations. Additionally, these pests can spread disease (CDC, 2014). With the increased trend toward intensification both in the United States and globally, it is likely that there will be more conflicts within communities between the general public and animal agricultural producers. Research can help with these conflicts both by providing more technical knowledge of odor mitigation and improving the communication between these two groups.

3-11.5 Nutrient Management

Most animal manure is applied to cropland, which can be beneficial as a source of nutrients and organic matter for soil, but can also be a source of groundwater and surface-water pollution. Animal agriculture can be a significant source of groundwater nitrates in areas of concentrated animal agriculture (Harter et al., 2012). Animal agriculture is a non-point source of nitrogen and phosphorus that contributes to algal blooms and subsequent dead zones in water bodies such as the Chesapeake Bay and Gulf of Mexico (Diaz and Rosenberg, 2008). As food animal operations have grown larger, the EPA and corresponding state agencies have developed regulations for animal feeding operations (AFOs) and concentrated animal feeding operations (CAFOs). These regulations have historically focused on the impact of terrestrial animal operations on water quality; however, some states, such as California, have moved toward permitting facilities for air emissions as well. In response, animal science and affiliated departments (e.g., crop and soil sciences) at land-grant universities have conducted research to address manure nutrient management and to reduce nutrient excretion from animal operations to the environment.

A criticism of CAFOs is that animal and crop systems have become decoupled, leading to the concentration of manure nutrients within relatively small geographical areas (Naylor et al., 2005). Previous integrated crop and animal agricultural production system research has demonstrated benefits of such systems, including increased biodiversity and better water quality and soil carbon sequestration, and nutrient cycling when compared to crop systems that do not integrate food animal production (Tomich et al., 2011; Barsotti et al., 2013; George et al., 2013). Examples of integrated crop-animal production systems include grazing ruminants on grain corn residue in the Corn Belt of the United States, dual-purpose wheat pasture systems in the southern Great Plains, agroforestry and silvopasture systems in the southeastern and western United States, and sod-based crop rotations (Sulc and Franzluebbers, 2014), as well as integrated terrestrial and aquatic systems (Godfray et al., 2010). Despite these examples, separate and specialized crop and animal production systems have become conventional in the United States (Sulc and Franzluebbers, 2014). Further basic and applied research on integrated crop and animal systems, including research into understanding the barriers and limitations of their adoption by agricultural producers would improve our understanding of ways to mitigate the undesirable environmental effects of the concentration of animal operations.

Research Priorities

Nutrients are necessary for crop production systems, and integrated animal-crop systems can enhance nutrient cycling; however, concentrated manure nutrients, if improperly managed, can also lead to environmental pollution caused by nutrient runoff and leaching. One research priority in this area includes:

• Continue and enhance research on the nutrient management of animal agricultural systems. Research should be directed to assessment of current and novel integrated crop-animal production systems, as well as the potential barriers and limitations to their adoption by agricultural producers.

3-11.6 Systems Evaluation: Environmental Metrics and Life-Cycle Assessment

A key challenge with sustainability is measurement and determining key indicators or metrics of sustainability in animal agriculture. When considering environmental impacts and, in particular, GHG emissions, recent research has focused on quantifying and mitigating environmental emissions per unit of output (e.g., per kilogram of product or protein) rather than per animal or per unit of land. The rationale for expressing environmental impacts per unit of output (known as the “functional unit” in life-cycle assessment [LCA]) is to report impacts on the basis of the animal production system's value to humans (de Vries and de Boer, 2010). Expressing impacts per unit of land can be problematic due to variations in soil types and climate, while expressing impacts per animal creates difficulties for comparisons across animal breeds and species. The efficiency of calorie production per hectare has been analyzed and animal production has been shown to be less efficient than crop production, with beef and other ruminant production being the least efficient (Cassidy et al., 2013; Eshel et al., 2014). The aquaculture enterprise is recognized as having the least adverse environmental impact of any animal production system. When compared to other animal protein production systems (beef, chicken, or pork), aquaculture is the most efficient and environmentally friendly as manifested in feed conversion, protein efficiency, nitrogen emissions, phosphorus emissions and land use (Bouman et al., 2013). For example, average nitrogen and phosphorus emissions for fish are 2.5 to 3.0 times lower than emissions for beef and pork at equivalent levels of protein production. However, others have suggested that when comparing ruminant efficiency to other species, the conversion of human edible or digestible energy and protein should be considered, rather than simply kilograms of feed or calories to produce a kilogram of beef or milk (Oltjen and Beckett, 1996; Wilkinson, 2011; Eshel et al., 2014). The proper functional unit of any one environmental analysis of animal production systems will depend on the goals of the analysis and should take into account that there are often multiple outputs of value from animal production systems (e.g., meat, milk, leather, and manure, which can have fertilizer value, are all outputs from dairy production). Transparency and clearly delineating assumptions are crucial for any environmental assessment of an animal agricultural production system. When evaluating environmental impacts from animal agricultural production, LCA is often used (Box 3-12). Different species and production systems have been evaluated in recent LCAs, including aquaculture (Cao et al., 2013), poultry (Pelletier, 2008; Pelletier et al., 2014), swine (Pelletier et al., 2010a; Thoma et al., 2011), beef (Pelletier et al., 2010b; Capper, 2011a; Lupo et al., 2013) and dairy (Capper et al., 2009; Thoma et al., 2013).

BOX 3-12

Life-Cycle Assessment and Application to Animal Agricultural Production. LCA has been often applied in studying and evaluating the environmental impact related to the production of meat and other agricultural products. A technique that is intended to (more...)

Adapted from its original use in evaluating industrial processes, LCA is essentially an environmental accounting system that sums impacts of interest across the entire production chain, from cradle to grave. For animal agriculture, this can include impacts from crop production, animals and their manure, processing, and transportation. Few LCA of animal agricultural products have conducted full cradle-to-grave assessments, but have instead focused on impacts generated at the farm gate with varying scopes and geographical locations assessed. Variation in scope and scale across LCA is a key challenge for making comparisons across published estimates. In an attempt to harmonize LCA methodological differences, the Livestock Environmental Assessment and Performance Partnership (LEAP), a collaborative effort of stakeholders from governments, nongovernmental organizations, and the private sector released draft guidelines regarding LCA for feed supply chains, small ruminants, and poultry production in early 2014 with plans to release guidelines for large ruminants in the near future.

Life-cycle assessment allows for evaluation of the impacts from the full production chain of a given animal production system, which can better account for the potential unintended consequences of changing one aspect of the production chain on the other phases of production. Additionally, consequence-related LCA techniques could be used to understand the environmental and economic tradeoffs associated with alternative uses of the biomass fed to animals (e.g., forages, byproducts, and grains), such as the production of biofuels or human food.

Quantifying uncertainty in LCAs is yet another challenge. Enteric methane emissions, for example, are not easily measured; therefore, LCAs rely on prediction equations to estimate methane emissions produced by ruminants via enteric fermentation. However, the accuracy of such models is fairly poor (Moraes et al., 2014), and there is a severe lack of empirical methane emissions data from grazing cattle. Remedying this uncertainty in enteric methane emissions should be a priority if there is interest in better understanding the formation of enteric methane emissions and mitigating those emissions. Because many of the environmental emissions from terrestrial animal agriculture and aquaculture are dependent on biogeochemical processes and can be altered by factors such as weather, microbial populations, and animal diet, there is a great need for empirical data quantifying emissions, testing mitigation strategies, and further developing mathematical models that can better represent observed data. A further challenge to LCAs is how to incorporate the social aspects of sustainability. While both environmental and economic impacts lend themselves to quantitative metrics, such a strategy with social considerations is difficult or impossible due to their subjective, qualitative nature.

Research Priorities

Incorporation of social sustainability concerns into LCA methodology is challenging. Currently, LCA researchers use different scopes, scales, and environmental emission prediction methods that can make comparisons across the published literature difficult or inappropriate. (e.g., environmental impacts are commonly expressed per unit of production such as per kilogram of meat but are also expressed on the basis of land area or feed or calorie conversion). Research priorities for this area include:

• LCA, an effective methodology to evaluate whole-animal food production systems, should be improved by further efforts, such as LEAP, to harmonize methodologies and increase the transparency of methods and assumptions.
• Researchers in animal science and related disciplines should work collaboratively with LCA researchers to conduct empirical research that improves the methodologies and reduces the uncertainties of LCA. Research should provide empirical data to quantify emissions, test mitigation strategies, and further develop and evaluate mathematical models that can better represent observed data and incorporate social sustainability.

Recommendation 3-12

Although socioeconomic research is critical to the successful adoption of new technologies in animal agriculture, insufficient attention has been directed to such research. Few animal science departments in the United States have social sciences or bioethics faculty in their departments who can carry out this kind of research.

Socioeconomic and animal science research should be integrated so that researchers, administrators, and decision makers can be guided and informed in conducting and funding effective, efficient, and productive research and technology transfer.

Recommendation 3-13

The committee recognizes a broad communication gap related to animal agriculture research and objectives between the animal science community and the consumer. This gap must be bridged if animal protein needs of 2050 are to be fulfilled.

There is a need to establish a strong focus on communications research as related to animal science research and animal agriculture, with the goals of enhancing knowledge dissemination, respectful stakeholder participation and engagement, and informed decision-making.

3-14.1 Integrating Research, Extension, and Education Efforts

As previously discussed, animal agriculture in the United States has become increasingly intensified and concentrated, leading to concerns of nutrient pollution. Researchers, particularly those at land-grant universities, have responded to the increasing concentration of animal operations by creating research, extension, and education programs in nutrient management and environmental quality relating to livestock and poultry operations. For example, the Nutrient Management Spear Program (NMSP) in the Department of Animal Science at Cornell University has been developed to conduct applied research, extension, and education. The program combines animal science, manure management, and crop and soil science disciplines to advance holistic nutrient management of dairy farms in New York State. One tool that the program has developed is the whole-farm nutrient balance calculator, which has been used by both dairy farmers and students, and can be used as an important component of adaptive management³ approaches that improve environmental quality and economic viability over time (Figure 3-6; Soberon et al., 2013). Additionally, a capstone course in whole-farm nutrient management is taught to animal science and crop science students. The course covers a wide range of topics including CAFO regulations, crop nutrient requirements, and the nitrogen cycle, with the final portion of the class allowing students to create a comprehensive nutrient management plan for a cooperating case farm (Albrecht et al., 2006). Similar courses are offered at University of Wisconsin (Managing the Environmental Impacts of Livestock Operations) and Penn State University (Nutrient Management in Agricultural Systems). Although the NMSP offers a great example of combining research, extension, and education efforts to advance the environmental sustainability of food animal production, similar programs do not exist at all land-grant universities. Many have a single waste management or nutrient management specialist housed on campus, who may not be associated with the Department of Animal Science but rather with the Department of Agricultural or Biosystems Engineering. Although this should not eliminate the ability to collaborate with animal scientists, the separation of animal waste specialists from departments of animal science can sometimes create an obstacle to integrated, collaborative research. This “silo effect” of separating disciplines, along with often limited funding support, can stifle the creation of transdisciplinary environmental management or sustainability programs for animal agricultural production that contain research, extension, and education elements.

FIGURE 3-6

Adaptive management for sustainability of agricultural farming systems. SOURCE: NRC (2010).

One useful tool in eliminating regional barriers and enhancing knowledge transfer in extension programing is the eXtension website (eXtension, 2014b). In the area of nutrient management, there is the Livestock and Poultry Environmental Learning Center, which has fact sheets, tools, and webinars on topics such as air quality, environmental planning, manure treatment, pathogens, and climate change (eXtension, 2014a). Additionally, there is a separate extension project funded by USDA NIFA, called “Animal Agriculture and Climate Change,” which created a free online course covering topics such as the science behind climate change, GHG emission sources, GHG emission mitigation and adaptation to climate change (USDA NIFA, 2013). In addition to the extension-focused “Animal Agriculture and Climate Change” project, there are other ongoing USDA NIFA-funded integrated research projects (integrated with extension and/or education components) that are related to either adaptation to climate change and/or mitigation of GHG emissions. Some of these projects include “Climate Change Mitigation and Adaptation in Dairy Production Systems of the Great Lakes region” (Project No. WIS01693) and “Resilience and Vulnerability of Beef Cattle Production in the Southern Great Plains Under Changing Climate, Land Use and Markets” (Project No. OKL02857). USDA also supports the Sustainable Agriculture Research and Education (SARE) program, which has provided funding for over 5,000 projects to producers, extension educators, researchers, nonprofits, and communities since the late 1980s (SARE, 2012). Funded projects have included on-farm renewable energy, no-till and conservation agriculture, nutrient management, crop and food animal diversity, and systems research (SARE, 2012).

While these examples provide an indication of potentially successful strategies, there is a need to further improve understanding and encourage wider application of outcome-based solutions for environmental management. Such an effort requires integrated research, extension, and education activities that are unlikely to be funded solely by a single producer group or private company because of resource limitations and, in many cases, a lack of clear commercial outcomes for research. Public funding and strategic public–private partnerships will be critical if progress in mitigating environmental impacts is desired. An example of a broad public–private partnership sustainability research effort, which goes beyond focusing just on environmental impacts, is the Coalition for a Sustainable Egg Supply (Box 3-13). Land-grant universities are uniquely qualified to conduct integrated research, as they have done for 100 years, particularly field-to-fork research that encompasses all phases of animal production to the consumer; however, the decline in public funding (both state and federal) in recent decades has led to an erosion of land-grant universities' abilities to meet societal demand for integrated research.

BOX 3-13

Coalition for a Sustainable Egg Supply. The Coalition for a Sustainable Egg Supply (CSES) provides a model for how public–private partnerships can be effective in initiating and supporting multidisciplinary research on the sustainability of animal (more...)

3-14.2 Integrating Research Disciplines to Understand Sustainability Tradeoffs

While there are often synergies across the three pillars of sustainability (environmental, economic, and social), there are also tradeoffs that have been largely neglected by past animal science research. For example, Capper et al. (2008) compared the environmental impact of three dairy production systems used to produce equivalent amounts of milk. The three systems included a conventional system, conventional system plus the adoption of recombinant bovine somatotropin (rbST), and an organic system. Capper et al. (2008) found that the adoption of rbST technology resulted in 8 percent fewer animals, 5 percent less land area, 5-6 percent reduced animal waste, and 6 percent reduction in GHG production compared to the conventional system. By contrast, the organic system resulted in a more negative environmental impact with a 25 percent increase in animal numbers, 20 percent increase in land area, and 13 percent increase in GHG emissions compared to the conventional system (Capper et al., 2008). Although the adoption of technologies such as rbST have economic and environmental sustainability benefits due to improving the efficiency of resource conversion into dairy products, the social sustainability implications of technologies used in animal production are less clear. In the United States, there has been a major shift away from selling fluid milk from cows treated with rbST in the past decade. Indeed, it is nearly impossible to find fluid milk sold without the label “from cows not treated with rbST (or rBGH).” The caveat to such labels is the “Food and Drug Administration (FDA) has determined there is no significant difference between milk from rbST treated cows and non-rbST treated cows.” Despite the assurance by the FDA that milk from rbST treated cows is safe, consumer resistance to rbST has been driven by concerns of IGF-1 levels in milk, the possibility of increased health risks to children exposed to milk from rbST treated cows, and potential impacts on dairy cattle welfare (Collier and Bauman, 2014). While these concerns have been determined to be unfounded (Collier and Bauman, 2014), consumer resistance remains, translating into retailer pressure for dairy farmers to stop using rbST (Olynk et al., 2012). It is unclear if consumers are aware of the potential environmental benefits of using rbST and if that would have any impact on the reluctance of many consumers to buy dairy products from cattle treated with rbST.

A more recent example of the tradeoff challenges for biotechnology is the use of the beta-agonist zilpaterol hydrochloride in finishing beef cattle. In the literature, both live animal experiments and a study using modeling techniques have found that use of growth-promoting technologies, such as beta-agonists, can decrease environmental impacts and resource use per unit of beef (Cooprider et al., 2011; Capper and Hayes, 2012; Stackhouse-Lawson et al., 2013). However, in August 2013, because of concerns over zilpaterol hydrochloride's impact on animal welfare, the company Tyson announced that it would stop harvesting cattle that had been fed beta-agonists in their slaughterhouses. The manufacturer of zilpaterol, Merck Animal Health, eventually removed the product from the market while investigating the animal welfare concerns. Lonergan et al. (2014) analyzed the effect of beta-agonists (both zilpaterol and ractopomine hydrochloride [Elanco Animal Health]) on cattle mortality. Though the mortality rates for the thousands of cattle in the datasets analyzed were very low, there was a significant increase in death loss for cattle treated with beta-agonists, particularly in summer months (Lonergan et al., 2014). Although the mechanisms or potential interactions that cause increased mortality and potential lameness (the primary welfare concern that led Tyson to its decision) still need to be elucidated, the case of zilpaterol hydrochloride illustrates the need for cooperation across disciplines within animal and veterinary sciences, as well as with social sciences to determine acceptability of biotechnologies such as beta-agonists. Consumers are likely largely unaware of the array of technologies used in animal agriculture, the reason for use, and the potential costs and benefits. The tradeoffs surrounding the social, environmental, and economic facets of sustainability have gone largely ignored and unquantified in the animal sciences, pointing to a need for further collaboration, training, and research in the future.

Beyond biotechnology, improved animal husbandry practices and housing systems that can affect animal longevity, fertility, and productivity can also affect environmental impacts per unit of output. Place and Mitloehner (2014) and Tucker et al. (2013) highlighted the synergy between some, but not all, animal welfare concerns and environmental quality. An example of a synergistic relationship between animal health and welfare and environmental impact is mastitis in the dairy industry. Reducing the incidence of mastitis (inflammation of the mammary gland that can be painful to the cow) has been shown to reduce dairy production's contribution to climate change, eutrophication, and acidification by decreasing the losses of human-consumable milk (Hospido and Sonesson, 2005).

Currently, there is limited research linking the disciplines of animal welfare, animal health, genetics, and the environment. The data gap on the connections and interactions of these disciplines represents an opportunity for animal science research to increase our collective knowledge and improve tradeoff analyses between environmental quality and other aspects of sustainable animal agriculture.

Research Priorities

There are several examples of integrated research, extension, and education efforts; however, relatively few were considered to be focused on sustainable animal agriculture and food systems. In some instances, the use of biotechnologies can simultaneously improve production efficiency and reduce environmental impacts per unit of output; however, the social acceptability and impacts of these biotechnologies on animal welfare should also be considered in research. Research priorities for this area include:

• A coordinated approach to engage with the public, policy makers, animal agriculturalists, and animal scientists is required to better understand, respond to, and communicate the tradeoffs of biotechnological solutions across the economic, social, and environmental components of sustainability.
• To tackle the issues of sustainability in animal agriculture, public funding should be guided by a twofold objective for support—projects that take a transdisciplinary approach and integrate research with extension and/or education efforts, and projects that continue to increase fundamental knowledge within the disciplines of animal science.