Location: Livestock Behavior Research
2025 Annual Report
Objectives
The long-term objective is tightly focused on optimizing animal welfare and productivity under modern farming conditions. The approach is to 1) focus on animal behavior and the cumulative effects of internal biological changes, 2) assess where challenges may exist, 3) develop alternative management strategies, and 4) determine how changes in behavior relate to physiology and productivity. We will focus on the following objectives:
Objective 1: To develop objective measures (physiology, behavior, production) of animal welfare and determine the impact of various production, housing, and environmental conditions; and develop management practices and methods to minimize any deleterious effect on welfare.
1.A. Clarify utility of hair and salivary cortisol as a measure of stress-load and determine its relationship to health and behavior in dairy calves.
1.B. Determine relationships between stress-load and feeding behavior in precision livestock farming.
1.C. Determining the thermal preferences of boars and growing-finishing pigs.
1.D. Evaluating the impact of in utero heat stress on maternal to fetal cortisol transfer.
1.E. To determine if feeding resistant starch to sows prior to farrowing and through lactation affects parturition duration and piglet welfare.
Objective 2: To optimize animal husbandry through the development of best practices to improve animal welfare and productivity.
2.A. Colostrum management practice and early-life morbidity and mortality demographic differences between purebred dairy and dairy-beef crossbred calves.
2.B. Improving Holstein dairy calf post-weaning growth performance and stress resilience through the provision of supplemental L-glutamine in milk replacer.
2.C. Improving environmental enrichment for pigs: learning, age specificity and worth.
2.D. Determine the impact of photoperiod on development of diurnal rhythmicity and welfare in pigs.
2.E. Improving piglet survivability and sow welfare through microenvironment management using precision technology.
2.F. To determine if a nesting environment can be simulated in a farrowing stall to increase sow and piglet welfare.
2.G. Cecal microbiota transplantation to reduce aggression in laying hens.
2.H. Determine if thermal perches reduce cold stress in caged laying hens.
2.I. Dietary synbiotic supplements to increase skeletal health and prevent lameness in broilers.
Approach
Our approach is novel and challenging, but our long-term strategy is to systematically address our goals of developing tools that can objectively assess animal welfare while concurrently developing welfare friendly production practices. The long-term objective is tightly focused on contemporary issues and thus is designed to optimize animal welfare and productivity under modern farming conditions. The approach is to 1) focus on animal behavior and the cumulative effects of internal biological changes, 2) assess where challenges may exist, 3) develop alternative management strategies, and 4) determine how changes in behavior relate to physiology and productivity.
Progress Report
Sub-objective 1.A. Clarify utility of hair and salivary cortisol as a measure of stress and determine its relationship to health and behavior in dairy calves. For developing stress indicators to measure long-term or chronic stress in dairy calves, all sample analyses for Sub-objective hypothesis 1.A.2. have been completed and a manuscript was submitted for publication in a peer-reviewed journal. The results reveal that salivary cortisol concentration in dairy calves is well correlated with the activation of the stress response system. The outcomes provide producers with a noninvasive method to monitor and to guide decision making related to managing animals under farm conditions.
Sub-objective 1.B. Determine relationships between stress-load and feeding behavior in precision livestock farms. All data collection for sub-objective hypothesis 1.B. has been completed and will soon be published . It was determined that overall, calf eating and drinking behaviors are affected by the automatic feeding systems, and their introduction should follow accurate and holistic structural planning to reduce associate risk factors for animal health and welfare.
Sub-objective 1.C. Determining the thermal preferences of boars and growing-finishing pigs. All data analysis for Subobjective hypothesis 1.C. 2. has been completed and will soon be published . It was determined that overall, boars preferred a temperature range of 24.10 to 26.90 °C and that breed (Duroc, Landrace, Yorkshire) had no impact on the thermal preferences of boars.
Sub-objective 2.B. Improving Holstein dairy calf post-weaning growth performance and stress resilience through the provision of supplemental-L-glutamine in milk replacer. It will determine if supplementing diets with L-glutamine, a synthetic amino acid, during the pre-weaning period can improve post-weaning performance and stress response in dairy calves. All data collection has been completed. Laboratory samples are currently being analyzed.
Sub-objective 2.E. Improving piglet survivability and sow welfare through microenvironment management using precision technology. Different temperatures are requested by piglets and lactating sows (approximately 32°C vs. 18-20°C) for sustainable performance. In the study, a developed microenvironment management system will be tested, i.e., an automaticallymaintain separating thermal environments for lactating sows and their piglets on an individual litter basis. The hypothesis is independently controlling the piglet and sow thermal environments to maximize thermal comfort wll improve piglet survivability and ultimately improve post-weaning growth performance through improvements in sow feed intake and milk output. All data collection has been completed and data is currently being analyzed.
Sub-objective 2.G. Cecal microbiota (bacteria from poultry digestive tract) transplantation to reduce aggression in laying hens. A study was carried out to examine the effects of cecal microbiota transplantation on injurious behaviors in laying hens. Phase 2, evaluating cecal microbiota transplantation effects on commercial chicken line (W-36) has been started. The gut microbiota (bacteria) has been recognized as a functional endocrine organ releasing multiple neuroactive factors to influence brain function in behavioral regulation. In the study, cecal content (bacterial) samples were collected from adult hens of two diversely selected inbred lines. Each donor line has unique behavioral features (i.e., nonaggression vs. aggression). The collected cecal samples were orally delivered to chicks of a commercial W-36 line. The results show that the chicks who received the cecal contents from the nonaggressive donors exhibited less both aggressive pecking and feather pecking when compared to the chicks who received the cecal contents from the aggressive donors. It is likely that the transferred beneficial bacteria colonized and released bioactive factors in the recipients’ intestinal tract, consequently, regulating the brain function via the bidirectional connection between the gut microbiota and the brain.
Sub-objective 2.H. Determine if thermal perches reduce cold stress in caged laying hens. Behavioral and physiological data have been collected, and data analysis is currently conducted. The results show that warmed perches reduce cold stress in laying hens.
Sub-objective 2.I. Dietary synbiotic supplements to increase skeletal health and prevent lameness in broilers. In this study, a mixture of selected chicken gut microorganisms with probiotic properties and prebiotic fructooligosaccharides was used. The trial of this study has been finished, and all behavioral, physiological, and production data have been analyzed.
Accomplishments
1. Reduced injurious behavior in laying hens through transplantation of gut bacteria. Injurious behaviors (aggressive pecking, feather pecking, and cannibalism) occur in all current housing environments and lead to approximately 25% mortality and vast economic losses (>$15 million annually) in commercial laying hens. Beak trimming is a common practice in the poultry egg industry to prevent these injurious behaviors but is also considered a painful procedure for hens. Recent studies have revealed that gut microbiota functions as an endocrine organ releasing multiple neuroactive factors to influence brain function in patients with neuropsychiatric disorders; and chickens have a similar central nervous system in regulating behaviors through a bidirectional communication between the gut microbiota (bacteria) and the brain as that in humans. ARS researchers at West Lafayette, Indiana, in collaboration with researchers from Purdue University, investigated whether transplanting cecal (part of poultry digestive tract) bacteria from the selected donor hens with less injurious behaviors would reduce injurious behaviors in the recipient hens. It was determined that the cecal bacteria transplantation was effective in reducing injurious behaviors and improved intestinal health, immunity, and stress response in recipients. The current results are expected to provide a scientific basis for developing next-generation probiotics (healthy bacteria) and/or neurochemicals that interact with the brain to alter hen behavior and reduce injurious behaviors.
Review Publications
Mohammad, A.A., Mahmoud, M.A., Zaki, R.S., Cheng, H.W. 2024. Effect of a probiotic supplement (Bacillus subtilis) on struggling behavior, immune response, and meat quality of shackled broiler chickens exposed to preslaughter stress. Poultry Science. https://doi.org/10.1016/j.psj.2024.104051.
Fu, Y., Cheng, H. 2024. The influence of cecal microbiota transplantation on chicken injurious behavior: Perspective in human neuropsychiatric research. Biomedicines. https://doi.org/10.3390/biom14081017.
Kern, J., Jorgensen, M.W., Boerman, J.P., Erasmus, M., Johnson, J.S., Pempek, J.A. 2024. Effect of repeated HPA axis stimulation on hair cortisol concentration, growth, and behavior in preweaned dairy cattle. Journal of Animal Science. https://doi.org/10.1093/jas/skae171.
Wurtz, K.E., Thodberg, K., Van Der Heide, M.E., Riber, A.B. 2025. Impact of feeding a high fibre diet and roughage on motivation for feeding in fast-growing broiler breeder pullets. Applied Animal Behaviour Science. 106529. https://doi.org/10.1016/j.applanim.2025.106529.
Araujo, A.C., Johnson, J.S., Graham, J.R., Howard, J., Oliveria, H.R., Brito, L.F. 2025. Transgenerational epigenetic heritability for growth, body composition, and reproductive traits in Landrace pigs. Frontiers in Genetics. https://doi.org/10.3389/fgene.2024.1526473.
Wen, H., Johnson, J.S., Gloria, L.S., Araujo, A.C., Maskal, J.M., Hartman, S.O., De Carvalho, F.E., Rocha, A.O., Huang, Y., Tiezza, F., Maltecca, C., Schinckel, A., Brito, L.F. 2025. Genetic parameters for novel climatic resilience indicators derived from automatically-recorded vaginal temperature in lactating sows under heat stress conditions. Genetics Selection Evolution. 56, 44. https://doi.org/10.1186/s12711-024-00908-4.
Wen, H., Johnson, J.S., Mulim, H.A., Araujo, A., Carvalho, F., Rocha, A.O., Huang, Y., Tiezzi, F., Maltecca, C., Schinckel, A.P., Brito, L.F. 2024. Genomic regions and biological mechanisms underlying climatic resilience traits derived from automatically-recorded vaginal temperature in lactating sows under heat stress conditions. Frontiers in Genetics. 15:1498380. https://doi.org/10.3389/fgene.2024.1498380.
Kim, J., Ni, J., Ogundare, W., Schinckel, A.P., Minor, R., Johnson, J.S., Casey, T.M. 2025. Sow and Piglet Behavior Characterization Using Visual Observation, Sensor Detection, and Video Recording. Biosystems Engineering. 15(6), 3018. https://doi.org/10.3390/app15063018.
Kern, J., Jorgensen, M.W., Boerman, J.P., Erasmus, M., Johnson, J.S., Pempek, J.A. 2025. Differences in colostrum management and transfer of passive immunity between purebred dairy and dairy × beef crossbred calves in Indiana and Michigan. Translational Animal Science. https://doi.org/10.1093/tas/txaf062.
Cheng, T., Pempek, J.A., Renaud, D.L., Proudfoot, K.L., England, Z., Wilson, D.J., Habing, G. 2025. Benchmarking hydration, navel health, and transfer of passive immunity in surplus dairy calves. Journal of Dairy Science Communications. https://doi.org/10.3168/jdsc.2024-0693.
Wurtz, K.E., Rasmussen, S., Riber, A.B. 2024. Research Note: Testing the validity of latency-to-lie tests without water for objective on-farm assessment of walking ability of broiler chickens. Poultry Science. https://doi.org/10.1016/j.psj.2024.104577.