W4173: Impacts of Stress on Performance, Health, and Well-Being of Animals
(Multistate Research Project)
W4173: Impacts of Stress on Performance, Health, and Well-Being of Animals
Duration: 10/01/2021 to 09/30/2026
Statement of Issues and Justification
With a growing global population and emerging challenges of climate change, the need for efficient production of animal protein is greater than ever before. It is estimated that the production of meat and other animal food products must increase by more than 50% within the next 30 years to accommodate a predicted world population of 9.6 billion. Furthermore, climate change poses a substantial challenge to the sustainability of current agricultural practices 1. Expanding animal agriculture is a complex challenge that is further compounded by the obvious disconnect between consumers and producers that results in misconceptions about animal agriculture 2,3. Thus, the challenge for US animal agriculture industries and the research institutions that serve them is clear: to create ways to increase the production of animal protein that are socially acceptable, economically sustainable, and environmentally friendly.
Stress in livestock increases mortality and morbidity, decreases growth efficiency, and results in less desirable end products 4-7. In order to increase production efficiency and address consumer concerns about animal well-being, it is critical to identify strategies that reduce the stress that a food animal experiences over its lifetime. A key step toward this objective has been the formation of this Multistate Research Project, which is aimed at capitalizing upon the expertise and resources across US research institutions to define and combat animal stress. The goals of our group align with USDA and US Farm Bill 8 priorities (Table 1) and address two Priority Areas of NIFA: Food Security and Climate Variability and Change.
Table 1. 2018 Farm Bill priorities addressed by the proposed W4173 Multistate Project
Farm Bill Priority Area for the Advancement of Science
Role of W4173
Agriculture economics and rural communities
Economic security in all aspects of the food chain is necessary for a strong economy. This requires adjusting to consumer-driven markets and public policies. Working to reduce animal stress and increase well-being will improve consumer acceptance of animal projects to increase agricultural prosperity.
Agriculture systems and technology
Systems-based, precision livestock farming (PLF) is essential to increasing production efficiency and integrating industry efforts. Research into individualized animal monitoring and management will benefit efforts to implement PLF in operations of all sizes.
Animal health and production and animal products
Finding new strategies for livestock management that reduce stress is essential for ensuring animal health and production. Alleviating stress also contributes to higher quality products.
Bioenergy, natural resources, and environment
This priority explicitly states a need for a “better understanding of how the changing climate affects agriculture.” Characterizing their response to environmental stress will allow the identification of more resilient, adaptable animals, and better management practices to increase sustainable production.
Food safety, nutrition, and health
Working to increase animal health and well-being will result in a more secure and sustainable food supply.
An inadequate level of action to address the issue of stress in animal agriculture would be unacceptable. The industry would lose consumer support and our ability to fulfill the nutritional needs of the growing population would be stunted. As the reality of climate change continues to emerge, producers cannot realistically relocate their operations to a region with a more tolerable climate. Rather, we must rely on scientific research to identify strategies that will allow producers and their animals to adapt to the changing world. The major topics of study in this Multistate - physiology, genetics, animal behavior, reproduction, nutrition, housing, and husbandry - will each contribute meaningfully to increasing the sustainability and efficiency of animal production.
The overarching goal and objectives of this project have remained relatively unchanged since the Project’s initiation in 1985, reflecting the magnitude to which stress continues to affect animal agriculture. Acknowledging that societal perceptions and science literacy are often overlooked in agriculture, we have added a new objective to specifically address challenges for outreach and the dissemination of science-based data to stakeholders. A large majority of consumers express that animal welfare influences their purchasing decisions 2,9,10, but research also shows that their perceptions of how animal products are produced is frequently inaccurate. For example, tail docking and dehorning are typically viewed by consumers as detrimental to dairy cow well-being 11, they think gestation and farrowing crates reduce the welfare and humane treatment of pigs 12, that animals experiencing heat stress reflect a failure of the producer, and that livestock should most often be housed outdoors 13. It is our goal that the research and extension efforts of our Multistate lead to a dialogue that dispels inaccurate beliefs and misunderstandings about animal well-being.
The membership of W3173 is diverse and represents complimentary expertise and interests. There are also diverse animal resources and handling facilities among stations for collaborative and comparative work. Our Project benefits from having members located throughout the country, in different climates, with different livestock breeds, and with varied management styles. This creates unique opportunities to compile comprehensive data on components of animal stress ranging from physiology and genetics to behavior and management. Therefore, the outcomes of this Multistate Project will broadly influence production practices, animal health and well-being, and profitability across diverse livestock sectors. Successful elements of the Project including ongoing research are outlined in the next section. Products from the group including publications, abstracts and presentations, extension materials, and theses/dissertations are included as an attachment.
Related, Current and Previous Work
In the past 4 years W3173 members built upon the strong foundation established over the preceding two decades by continuing to pursue innovative research in the areas of animal stress and well-being. Participants represent 31 US states, 2 US territories, and New Zealand; interactions among the group resulted in the initiation of new and expansion of existing collaborative work to address the project objectives.
Membership expertise includes the areas of animal nutrition, immunology, physiology, genetics, engineering, meat science, precision livestock technology, and behavior; the diversity of our interests and skills boosts the existing and potential collaborative activities of the group. Additionally, work across objectives spans all major food animal species, horses, exotic (zoo) animals, and rodent models. Since its establishment in 1985, the importance of understanding and mitigating animal stress is arguably at its highest given the rising global demand for animal products, the challenges created by climate change, and the increased consumer insistence on proper animal well-being. New members have joined those long-associated with the Project to contribute to our productivity and expand our reach. In the past 4 years, over 90 peer-reviewed publications that directly address one or more of the project’s objectives have been generated by participants. In addition, 21 graduate students have completed their training, internet resources including webinars and interactive web pages have been created, and outreach related to animal stress has occurred through formal and informal extension programing. Members have also contributed to the development of widely-used guidelines for animal care and use such as the AgGuide 14 and Quality Assurance materials.
In searches for redundancy, heat stress is mentioned as a topic of study in Multistate NC1184 and NCERA57, and various types of stressors are studied in NC1029 (Animal Behavior and Welfare). We do not find these conflicts problematic as our focus on heat stress is much more encompassing than its impacts on muscle as studied in NC1184 or swine reproduction as studied in NCERA57. Furthermore, several members of W3173 are also members of NC1184 and other researchers are also involved in NC1029. Due to similar interests between our Multistate and NC1029, we held a joint meeting in 2019 to discuss ways in which we could collaborate. Stress as a topic of interest is also found in W3112 (ruminant reproduction), NE1748 (mastitis), and W3112 (Reproductive Performance in Domestic Ruminants), but again with limited overlap due to the very specific topics of study within the other Projects.
Moving forward, W4173 will continue to serve as the US’s lead organization for research efforts to better characterize, understand, and mitigate animal stress. As a result of annual meetings and feedback from the prior Project review, we have refined our objectives. The original objectives have been revised for clarity but remain inclusive of our broad research scopes, species of interest, and methodologies. A forth objective has now been added to formalize our commitment to dissemination of research outcomes to the scientific community, stakeholders, and the community at large.
Past and ongoing/planned work by W3173 participants is outlined below categorized by 5 major themes of study. A large proportion of the citations included reflect work by participants in past or current iterations of the Project.
Identifying Stress: Substantial efforts have been dedicated to enhancing our ability to objectively gauge animal stress. The primary focus of this Project’s prior iterations was how to best measure stress in livestock – particularly via body temperature. The resulting methods to more accurately and easily measure body temperature (reviewed in 15) have included the use of continual measurement by indwelling temperature monitors 16-18 and no-touch measurements by infrared imaging 19,20. However, even when body temperature and other physiological parameters are measured accurately, such data are without context when expected values under normal conditions are unknown. To that end, ongoing work within the group continues to define the baseline values for physiological parameters in animals by species, age, and reproductive status. Recent outcomes in this area include the identification of differences in body temperature among heat-tolerant vs heat-susceptible breeds, in animals of varied age, and in females at different stages of their reproductive cycles 21-23. Project participants have also built algorithms to predict body temperature based on environmental data, allowing a non-invasive identification of animals at risk due to excessive heat 24,25. The use of statistical modeling found that body temperature in livestock “lags” behind the environment and that lag time differed by time of day 26. Studies in dairy cattle provided context for several outward indicators of stress (e.g. respiration rate, panting) and examined both the optimal frequency for observations and the best time of day to determine heat load 23,27. These and similar studies have helped researchers and producers better identify stress and monitor well-being in animals, providing useful information for use in management decisions such as deciding on an optimal feeding time and timing the implementation of cooling measures.
Researchers in this group are developing methods that utilize behavioral data to identify stress and to better understand how behavior changes during stress events. Historically, behavioral studies are labor intensive. However, members of our group are working together and independently to implement camera-facilitated artificial intelligence (AI) systems to study behavior, social interactions, and even to predict performance. The ability for cameras to continuously “watch” animals without interruption or subjectivity has substantial benefits compared to periodic, in-person observations 28. For some AI systems, accuracy is high enough to continuously identify each individual animal in a large group in near real-time and over a period of months. Activities that can be identified by AI systems include time spent feeding, walking, or fighting, changes in activity level throughout the day and from day-to-day, and social interactions with others. Behavioral changes due to stress have also been modeled and monitored using the application of social network analysis 29 and optical flow algorithms 30. Similar analyses of behavioral data have found that tail docking in pigs decreased the frequency of unwanted tail biting behavior without altering productivity. This outcome is important, as a survey of largely rural populations showed that tail docking is perceived as detrimental to well-being 12. AI technology is now commonly used to document intricacies of movement, to identify gait or structural abnormalities, and is being optimized to allow identification of ill/injured animals prior to the onset of clinical symptoms 31-33.
Environmental Stress: Climate change is an emerging concern for all areas of the livestock industry. Extreme environmental events (e.g., drought, extreme heat, blizzard) lead to morbidity and mortality, and less severe acute and chronic environmental stressors reduce reproductive fitness and growth efficiency, alter metabolic function, and lessen carcass value 34-37. Studies like those discussed in the previous section have provided tools to identify heat stress in livestock through changes in body temperature, respiration rate, behavior, and blood biomarkers. These advancements enable more in-depth research regarding the effects of heat stress on molecular physiology, immune function, reproduction, and carcass merit. Across stations researchers involved in this Project share the objective of understanding the impact of environmental stress on livestock. The ultimate goal of this work is to better inform management practices in order to minimize unwanted impacts of stress. This focus is spearheaded by the Project’s membership, which reaches across regions to create opportunities for collaborative and comparative studies across differential geographies, species, and breeds. As climate change continues to threaten sustainable animal agriculture, heat stress will continue as a primary emphasis of this Project.
Collaborative work is ongoing to better understand how genome regulation changes in times of stress and how this affects physiological outcomes in livestock 38. Understanding molecular changes will yield potential insight into targeted therapeutics and allow selection of genetically-suited animals for a particular environment 39. Such data include transcriptomics to study adipose and skeletal muscle, ex vivo metabolism studies, evaluation of stress marker in blood, and bioelectrical impedance analysis to study carcass traits in live animals. These studies address important industry concerns, such as demonstrating that β-agonist supplements so not appear to amplify the impact of heat stress 38,40-42. The impact of heat stress on adipose and skeletal muscle of ruminants is also being clarified by transcriptome analyses 41, and physiology studies are examining specific effects (or lack thereof) of heat stress on molecular components such as fatty acid composition in adipose 43. Carcass and growth performance data show a clear negative impact of heat stress on livestock (reviewed in 6,44), and thus our group continues needed investigations to understand the specific mechanisms through which heat stress impacts animals.
Several stations are working to identify management and housing options that best mitigate heat stress. Cooling pads and floors for sows 45,46, and air, moisture, and flooring manipulation in dairies 47-52 are being evaluated for their impact on animal well-being and economics. In dairy, effective cooling systems increase milk yield and dietary intake, and decrease other negative heat stress responses, although this requires that the system used matches the environment. The use of misters to cool horses after intense competition and the use of shade by horses in hot climates are also being studied by Project members, which will help to advise horse owners and managers of the necessity of shade in pasture settings 53.
Nutritional Stress: Proper nutrition does not induce stress, and in times of stress helps animals mitigate its negative impacts. However, inadequate food availability, rations missing essential nutrients, or an excess of certain dietary components can add stress. It is well-established that feed intake is reduced in times of stress. One example of work on this topic from our group is the creation of a rodent model of hypophagia that is observed during heat stress. Pair feeding in mice is focused on identifying molecular means by which this change in feeding behavior occurs 54. Studies in heat-stressed sheep and their pair-fed controls is demonstrating that reduced animal performance cannot be attributed to decreased intake alone, but is also caused by stress-invoked changes in physiology 40. Work in poultry is identifying differential molecular and proteomic changes in the hypothalamus based upon genetic background in models of anorexia 55-59 and work in pigs is determining how feed withdrawal impacts Salmonella 60. These studies are creating a more in-depth understanding of the mechanisms by which stress reduces feed intake and alters animal well-being and productivity.
Several stations are involved in collaborative work to understand how supplements alter animal health and well-being. Supplementation of livestock with β-adrenergic agonists is a common practice shown to increase growth efficiency. In 2014, a popular β-agonist, zilpaterol HCl, was anecdotally linked to concerns about animal stress and a deficit of well-being. Studies in heat stressed lambs supplemented with β-agonists are helping elucidate the molecular pathways by which zilpaterol HCl and other β-agonists act and whether there should be concern regarding their use in hot climates. Ex vivo metabolic studies demonstrated that zilpaterol (but not ractopamine) HCl increases glucose oxidation but not glucose uptake in skeletal muscle 42. Maximum respiration and spare respiratory capacity of mitochondria is also increased in muscle cells treated with β-agonists 61. Studies in these lambs as well as follow-up studies in cattle have produced no notable results indicating that β-agonist supplements further endanger well-being in heat stressed animals. In fact, heat stress’ effects on body temperature, respiration rate, and other indicators in cattle and sheep are partially mediated by β-agonists 40.
Additional studies are focusing on how the availability of trace minerals alters animal well-being and performance and how minerals interact with feedstuff components. These studies include the evaluation of minerals in feedlot steers and bulls, as well as in cows 62-65. Molybdenum in the water supply is also being examined for potential toxicity 66,67. In chickens, supplementation with probiotics is being studied to mediate adverse effects of heat stress 68 and inflammation 69, and supplementation of tryptophan is being evaluated as a possible calming agent in horses 70. The effect of perinatal nutrition on behavior, immune function, and performance is also an area of interest across species. For instance, feeding L-glutamine prior to weaning and transportation stress is being studied for its benefit to performance and behavioral indicators of stress 71. Interest in gut health responses to nutrition or other stressors is an area of interest to several newer members of the Project, and we expect work in this area to expand.
Housing/Husbandry/Transportation Stress: Environmental stress can arise from excessive heat or cold. In addition to technologies that provide cooling to heat-stressed animals, housing options are being scrutinized to determine which are the best options regarding animal well-being, efficiency/practicality, and economic feasibility.
Work by Project members includes evaluation of dairy hutches using stress biomarkers in blood and saliva of calves. Additional work has examined how the amount of space provided to calves after weaning or castration impacts their immune function. Initial indications include that greater space decreases stress; this outcome provides guidance for producers 72-75. Likewise, flooring and bedding options are being considered with respect to how they alter animal behavior, stress, and productivity 76,77. Studies addressing consumer demand for free-range or cage-free management are of increasing importance. In poultry, an emphasis on cage-free housing has led to concerns for increased mortality and aggression among birds 78. Members of our group are examining how stocking density of broilers impacts their well-being and overall performance so that management practices can be tailored to breed type and stage of growth 79. In swine, topics under investigation include floor space for gestating sows, flooring that is best suited for comingling, heat source options for piglets, and the availability and placement of feed and water sources 80-84.
The design of facilities and containment mechanisms can influence an animals’ stress and the safety of the people handling them. Building upon prior studies in which electronic stimuli were used to promote beneficial behaviors, Mumm et al. 85 is examining the use of electronic stimuli to encourage a sow to stand when other technology has identified that she is crushing a piglet. New ideas of Project members include exploring the use of GPS collars to contain rangeland cattle.
Transportation of animals is complex, and this group is studying several variables of transportion such as the methods used to load animals, indicators of well-being during transport, and immune challenges resulting from transport. Ideas including the use of conveyor belts to load nursery pigs 86 are being explored as we continue to try to identify ways in which to make transport safer, more economical, and less stressful. Heat stress during transport of young pigs is also being investigated 87, with the concern that the fitness of animals subject to this stress early in life have decreased productivity. Conditions and handling practices on the way to the abattoir can also lead to bruising, which is a concern for well-being and product quality 88,89. The impact of stress on the final product is of great concern and clearly influences consumer demand for animal products and their perception of the industry. To that end, studies of the effect of stress on final products such as liver abscesses are under way 90. These studies have an impact on both the scientific community and the industry, and are often incorporated into informational documents for the industry such as in Transportation Quality Assurance handbooks.
Husbandry decisions include the best way to wean young animals. Stress at weaning is significant and future growth can be impacted by the timing and conditions of weaning such as the level of nutrition offered 91-93. Expanded studies of weaning are planned by current and new members of the Project.
Finally, managing animal stress and well-being extends to defining methods of euthanasia that are humane and that do not alter product quality. Recent and ongoing work from the group is examining various techniques for stunning/euthanasia to address this topic 94,95. Further, as the need for mass depopulation became a reality as a result of the COVID-19 pandemic 96,97, the relevance of this area of study has again come to the forefront. The need for training and development of protocols in this area has also been highlighted by review papers from our group 98,99 and will remain an area of investigation.
Reproduction and Disease: Studies of poor reproductive fitness as a result of stress are plentiful, as the sustainability of production relies upon a herd’s ability to maintain its numbers. The effects of maternofetal stress on the fetal programming of well-being and growth performance in offspring has been an emerging area of research over the last few decades. Researchers in this group are seeking to characterize the effects of prenatal stress on postnatal outcomes in ruminants 100-103 and swine 104-106, as well as in rodent models 107. These studies are identifying specific mechanisms for adaptive programming such as changes in adrenergic tone 101,102 and inflammatory regulation of skeletal muscle 103,108. They are also testing potential strategies to prevent or correct these changes, including maternal O2 supplementation 102, β-adrenergic system manipulation 101,109, anti-inflammatory agents 103, and nutrient-dense diets 105. These ongoing inquiries will address additional areas such as critical windows for interventions, species- and breed-specific therapies, and underlying genetic and epigenetic components of these responses. The impact of heat stress during gestation is also a focus in swine 106,110.
Project members are also active in areas of research ranging from stress during bull testing 111, to risks associated with artificial insemination 112 and means to protect against mastitis 113. New membership into the Project is expanding this work to include studies of calcium homeostasis and supplementation in order to understand and reduce inflammatory disease in the postpartum dairy cow.
Although many studies involve the assay of immune function in animals, studies of specific disease primarily have focused on bovine respiratory disease (BRD). To identify risk of BRD, producer surveys associate risk with herd size, type of housing, and the use of nonsaleable milk 114. In calves, plasma haptoglobin has been identified as useful biomarker of BRD 115. The Project is positioned, however, to expand studies of disease as the need arises and/or as new membership may dictate.
Identify and characterize the biology of stress responses that affect animal well-being and production
Identify genetic and epigenetic components of animal stress and how they impact performance and well-being
Develop tools, advanced precision livestock technologies, and management strategies that reduce stress and enhance animal well-being
Disseminate research findings, new technologies, and management recommendations to scientific, industry, and consumer audiences
W3173/W4173 members share the common goal of understanding and minimizing the impact of stress on agricultural and wildlife animals. This multistate project allows us to more efficiently address this goal by leveraging our combined expertise, facilities, resources, techniques, and information. In this section, we outline the collective methodologies that our group is using to achieve our four objectives with the caveat that as new issues arise and/or new members join, the breath of our research may expand.
Collaborative studies between Arizona and Nebraska scientists are seeking to define the individual and combined impacts of heat stress and β-adrenergic agonist supplementation on well-being and production efficiency in ruminant livestock. The studies include examinations of genetic/genomic, physiological, and anatomical changes in response to zilpaterol/ractopamine supplements in thermoneutral or heat stressed feedlot lambs and steers. Specifically, live-animal growth and stress response outputs are being combined with live-animal and postmortem analyses of skeletal muscle metabolism, fat mobilization capacity, tissue composition, fat and muscle transcriptomics, cardiovascular function, gut microbiome, organ pathologies, and foot/lower leg lameness indicators. These studies will also include comparing differences in outputs between Bos taurus and B. indicus breeds and between differential mitochondrial DNA variants. Obj. 1, 2
Scientists in Wisconsin, California, Arizona, and Texas are seeking to improve strategies to combat heat stress in dairy cattle to minimize the effects on health and milk production. Refinement of existing spraying strategies (e.g., time on and off) will improve the efficiency of water and energy usage. As part of these efforts, behavioral biomarkers including drool rates for stress and immune resilience are being identified. These will be used in conjunction with immunological and physiological biomarkers to assess and modify animal management. At the same time, research is being performed to assess the effectiveness of conduction and air convection cooling strategies and supplementary air flow at the feed bunk, all of which use less water and energy than traditional misters. Obj. 3, 4
Scientists in Nebraska, Arizona, and Colorado plan to collaborate on the extension of studies that seek to understand the effects of maternofetal stress during critical windows of gestation on fetal programming of growth capacity and metabolic function. Using two ovine models for sustained maternofetal stress that each produce placental insufficiency and intrauterine growth restriction, these studies are designed to provide a better understanding of the changes to stress-responsive signaling pathways in muscle, fat, and pancreatic islets. Obj. 1
To better understand stress-influenced behaviors and how stress impacts health, scientists in Nebraska, Kansas, and Minnesota are developing methods for long-term artificial intelligence tracking of livestock and zoo animals in confinement systems. Camera systems capture body position, orientation, location, movement, and proximity to other animals or structures; those data are then fed into algorithms that predict known behaviors that best match the data (i.e. lying, eating, fighting). Patterns in predicted behaviors can then be used to identify stress/health issues, determine social hierarchies, estimate growth/body composition, and evaluate gait. Obj. 3
Animal adaptions to heat stress may be characterized by longer morning and shorter afternoon lags in body temperature-to-air temperature ratios. Scientist from the Nebraska station are teaming with USDA scientists to develop methods using temperature lags to characterize heat stress adaptability in cattle. Analyses methods were developed to categorize animals into four levels of heat stress as a possible management tool, which is being applied to cattle in US MARC heat stress experiments. Studies are intended to define parameters for 4 heat stress categories (normal, alert, danger, and emergency) using morning and afternoon lag values. Obj. 3
Behavioral, physiological, and immunological biomarkers for rapid identification of animals in clinical and subclinical states of distress, injury, and sickness allow producers to make more timely management decisions. Scientists in Kansas and Nebraska are working to create protocols for pen-side tests to distinguish pigs with sub-clinical injuries from uninjured controls. In addition, protocols for testing cortical function through somatosensory stimulation are being developed, and the efficacy of a technology that uses aversive vibrations and electrical impulses to cause sows to stand to avoid piglet crushing is being tested. Obj. 3, 4
Scientists in Kansas, Wisconsin, and Nebraska are developing automated environmental enrichment devices for use by boars. Data regarding engagement with the device will be used in an attempt to distinguish pigs with sub-clinical injury from uninjured pigs and predict semen quality. Obj. 3
Scientist from Virginia and Delaware are identifying hypothalamic neuronal pathways that are involved in appetite responses to nutritional and thermal stresses in broilers. One study uses a model developed in-house in which chicks are delayed access to feed and also transiently exposed to either elevated or reduced temperatures. This allows the group to elucidate epigenetic mechanisms that regulate gene expression that lead to persistent changes in feeding behavior and affect long-term growth performance and well-being. Obj. 2, 3, 4
To characterize traits that make specific breeds better adapted to tropical environments, scientists in the Virgin Islands are studying the relationships between body temperatures and ambient temperatures in Senepol and crossbred heifers as well as in St Croix White and Dorper/St Croix White ewes. Findings will be disseminated to local livestock producers, who must make decisions on breeding and management strategies that best fit the climate. Additionally, maternal water restriction has been used to promote the cessation of milk production during early (60d) weaning of lambs, and is now being assessed in St. Croix White ewes where weaning occurs at 120d. Obj. 1, 4
Swine industry concerns exist regarding pain or distress, morbidity or mortality, and deleterious effects of climate variability. Specifically, weaning and transport of pigs are inherently stressful but entirely necessary procedures. Scientists in Indiana are seeking to determine the efficacy of L-glutamine as an antibiotic alternative following weaning and transport of young pigs. Parallel efforts are focusing on the development of implantable temperature monitors that allow continuous assessment with minimal disturbance and the development of cooling pads to reduce the impact of heat stress in lactating sows. Obj. 1, 3, 4
Scientists in Minnesota are investigating the phenomenon of tail biting in pigs by monitoring changes in their activity. The hypothesis is that changed activity levels predict outbreaks of tail biting, and that these can be monitored by an optical flow platform. Behavior, skin lesions, tail damage, growth performance, and carcass traits are being compared between pigs with docked or intact tails. Additionally, biomarkers for pain (Substance P), stress, and immune function (Total serum protein, Ig-G) of tail biters, victims, and controls pigs are being assessed. Behavior monitored by video-recording is being analyzed using both a traditional method (scan sampling) and optical flow analysis, and these data are being compared relative to evaluations of social structures. Obj. 1, 3, 4
To better understand the relationship between body temperature and grazing behavior of tropically-adapted hair sheep, scientists in the Virgin Islands are utilizing behavioral observations, GPS tracking data, and body temperature measurements in a flock of grazing ewes. Ewes are being evaluated for 1 week each month over the entire year. These techniques have demonstrated that these sheep are adapted to the tropical climate and frequently graze at times of the day with the highest THI and solar radiation. Comparisons of body temperatures in St Croix White ewes and Dorper/St Croix White crossbred ewes has been used to show adaptations of the former to the high heat and humidity in the tropics. Obj. 1, 3
Scientists in Colorado are working with industry partners to research practical approaches for maximizing animal welfare at slaughter and profitability of the system. Planned future research includes continued exploration of improved stunning practices at plants, development of standardized industry benchmarks for well-being measures such as mobility and bruising, and investigation into measures of pain related to management procedures. Obj. 1, 3, 4
After exercise, horses must often be cooled quickly with a cool-water drench until physiologic parameters have returned to normal. Researchers in Kentucky are investigating the efficacy of air movement by fans as an alternative to misting tents, which drop air temperature and increase humidity, thus reduce evaporation effectiveness. If proven more efficient for cooling horses, the data supporting this strategy will be shared with horse industries. Obj. 3, 4
In tropical climates, heat stress reduces nutritional efficiency and performance in small ruminants, making it necessary to evaluate the impact of feeding strategies on growth and reproductive performance. Scientists in Puerto Rico are evaluating growth of heat-stressed feedlot lambs fed TMR with two energy levels, as well as the effect of season on ram semen quality. To identify optimal feeding strategies, baseline temperature, respiration, and heart rates are being identified in native and pygmy goats and in sheep. In addition, the effects of adding 4% DMD dietary fat sources on physiological parameters, dry matter and water intake, and nutrient digestibility in growing lambs is being identified. This work will expand the understanding of the effects of heat stress on small ruminant performance and reproduction. Obj. 1, 3, 4
Conductive cooling is a promising technology for relieving heat stress in dairy cows. Scientists in New York are developing waterbeds placed in stalls to serve as heat exchangers. Initial evidence from studies with two types of bedding (sand and sawdust) and 4 bedding thicknesses indicate that the systems may increase milk yield and decrease rectal temperature and respiration rates, thus providing a useful tool to alleviate heat stress in dairy cows. Additional studies will assess unwanted moisture condensation in the bedding of these systems. Obj. 1, 3, 4
Poor air quality and ventilation in confinement systems can be detrimental to the health of the animals as well as of their human caretakers. Scientists in Pennsylvania are using computational fluid dynamic modelling of ventilation in hen houses and swine pits to find the best facility layout and management systems to maximize air quality and climate control. Obj. 3, 4
Current colostrum management recommendations fail to account for non-immunoglobulin components in the first and subsequent milking of dairy cows, and the potential detrimental effects of industry-wide practices such as freezing and heat-treatment. Scientists from New York are attempting to address this gap in knowledge by assessing milk quality and immune components at sequential stages in the milking/preservation processes to create recommendations for better using these immunologically active components. Parallel inquiries include the effect of metabolic stress and hypocalcemia on immune responses in postpartum cows as well as the effects of supplemented amino acids and calcium. Obj. 3, 4
Inhibiting trace mineral absorption impacts animal health and productivity; solubility of a given element within the digestive tract is key to its absorption rate. Using in vitro techniques, scientists in Colorado are examining the impact of pH, feed type, and trace mineral concentrations on Cu and Zn solubility in cattle consuming various various feedstuffs. Obj. 1
Research has focused on quantifying heat stress in beef cattle and swine species and developing genetic evaluation to select more environmentally robust animals. Scientists in Georgia are performing research aimed at developing computer algorithms to use IR images to estimate body surface area and skin surface temperature. Findings will then be compared with measured environmental (air temperature, relative humidity, air velocity), physical (body weight, surface area, hair-coat properties), and physiological (skin temperature, rectal temperature, vaginal temperature, sweating rate, respiration rate, sonogram measurements of skin, fat and muscle thicknesses) parameters. Obj. 1, 3, 4
Research by scientists in Arizona aims to better understand the mechanisms by which feed intake and milk production are decreased in response to heat. These studies take advantage of a rodent model of heat stress and pair-fed hypogalactia developed in-house that mirrors the heat-stressed cow. Future studies will increase the understanding of the role of histamine signaling and the resulting decrease in digestive tract and mammary gland blood flow in the hypophagia and hypogalactia models of stress. The information produced by these studies will also serve as a major component of extension programming designed for the state’s dairy industry. Obj. 1, 4
With growing consumer interest in ranching practices related to animal health and welfare, scientists in Oregon are performing research aimed at reducing the impact of weaning stress in calves with trace mineral supplements prior to weaning and with a bovine appeasing substance. Additional studies are being designed to assess the impact of creating a virtual fence with GPS-controlled shock collars on grazing behavior in cattle. Obj. 1, 3, 4
Understanding how cattle and other grazing ruminants adapt to their environments will create better management practices to minimize the effects of stress and maximize production. Scientists in Ohio are seeking to better understand the effects of stress associated with climate change in the Midwest, particularly intense rainfall events in winter and spring and dry heat in the summer. Studies are being performed that will examine the effects of mud on health, well-being, and performance of beef herds. These studies will determine the energy costs that mud creates for gestating cows and heifers, evaluate behavioral and physiological responses to mud, and assess options for attenuating the effects of mud on gestating beef cows. Obj. 1, 3, 4
Scientists in Maryland are seeking to identify the individual and combined impacts of breed and husbandry practices on physiological and behavioral indicators of broiler health and well-being. Specifically, projects focus on growth rates, disease, and heat stress in broilers and their respective contributions to health, stress, and welfare. Animal experiments include assessments of intestinal histology, bone growth, and sickness behavior in multi-breed populations of broiler chickens challenged with Salmonella or raised in pens with or without spotlights and structural enrichments. Additional studies will include assessments of behavior via video recordings, development of algorithms to detect and predict health with deep learning neural network computer vision models, and a field study on an organic commercial broiler farm. Obj. 1, 3, 4
Measurement of Progress and Results
- Peer-reviewed publications outlining research results. Comments: These outputs will provide other researchers, educators, and stakeholders tools and guidance regarding animal stress and well-being.
- Presentations in international, national, regional, and local settings to audiences consisting of lay public, consumers, industry partners, academics, and/or scientists. Comments: In-person meetings and presentations will provide essential avenues to build and bolster collaborations.
- Opportunities for graduate student researchers to gain experience in experimental design, data collection and analyses, dissemination of results, and team science. Comments: Building these skills in our next generation of researchers is essential to continued success.
- New and refined tools for the evaluation of animal stress and behavior. Comments: Methods that are less labor intensive, less intrusive and invasive, and allow for continuous data collection will increase accuracy in detecting and quantifying stress levels.
- Novel ideas for combining expertise to create more comprehensive studies of animal stress and well-being. Comments: Interactions among the group that span across species and disciplines will strengthen the overall impact of the Project.
Outcomes or Projected Impacts
- Projects directed toward the four objectives outlined in this proposal will advance our understanding of the biology of stress responses and how to measure important components of these responses that reflect well-being.
- Work to build improved on-line resources for the public will also help dispel myths about animal agriculture, provide easy to access resources for producers to find scientifically-relevant information for management, and for researchers to build and expand collaborations in this area of study.
Milestones(2022):A new link will be made available on the nimss.org W4173 Project site to a spreadsheet that lists participants, their major area(s) of study, collaborative needs, and expertise they can offer. This database will more efficiently connect members of the Project and further build collaborations.
(2023):The group will create an easily-accessible webpage that outlines Project membership, major activities, accomplishments, and impacts. Animal stress is a societal concern, and creating a one-stop-shop where the public can learn about research and recommendations in this area will help to address issues of science literacy and outreach.
Projected ParticipationView Appendix E: Participation
The most effective outreach requires a multi-faceted approach. Traditional methods to disseminate information including peer-reviewed scientific publications, participation in conferences and workshops, and extension events will continue as previously (see attachment for 2017-2020 outputs).To better relay Project information to stakeholders outside the scientific community, we have defined a fourth objective for which dissemination of information will be an explicit focus. In addition to long-standing extension strategies for outreach, we plan to develop a new website for the W4173 Project that will highlight our research, its impacts, and successes. This will be an easily-accessible tool by which the public can learn about our work and through which collaborations can be built. Once active, we plan to update the site annually to include impact statements from our work and descriptions of any current issues/concerns that arise related to our research foci. In 2020, W3173 members participated in an USDA-facilitated Impact Writing Workshop, which will increase the effectiveness of this website. The site will also contain links to online presentations and educational materials created by Project members, and it will provide information about members by their area(s) of study. As several topics of focus within our group have significant societal prominence and importance (e.g., climate change, animal well-being), this will be a means by which scientifically-sound information can be made available in a lay format. Furthermore, the majority of stations participating in W4173 already have a digital presence for their extension programming; thus, we hope to centralize already existing resources so that information can be easily accessed. An example of success in building an on-line resource is the Penn State University Virtual Farm website, which was designed with substantial contributions from W4173 Project member Dr. Fabian: https://www.virtualfarm.psu.edu/.
The W4173 Project officers shall consist of the Ex-Chair, Chair, and Secretary.
- Ex-Chair: The member who in the prior reporting year organized and led the annual meeting and prepared the annual report. This person is to advise the current Chair and assist with any logistical or organizational questions or in compiling and submitting the report.
- Chair: The Chair of the committee is responsible for organizing and conducting the annual meeting, preparing and submitting the final version of annual report, and assuring that tasks and assignments are completed.
- Secretary: The Secretary is responsible for keeping records on decisions made at meetings and assisting in the preparation of the annual report.
Each year, a Secretary will be elected by those members attending the regular annual meeting prior to its adjournment. At this time, the previous Secretary will become the Chair and the previous Chair will become the Ex-Chair for a 1-year term. An alternative Chair or Ex-Chair may be elected or appointed if necessary.
Members: Committee membership requires active participation and information exchange. Submission of annual station reports and regular attendance at the annual meetings are expected for all participants and will be documented in the annual report to NIFA.
Administrative guidance will be provided by the assigned Administrative Advisor and NIFA Representative.
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