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ARS Home » Midwest Area » West Lafayette, Indiana » Livestock Behavior Research » Research » Research Project #425202

Research Project: Safeguarding Well-being of Food Producing Animals

Location: Livestock Behavior Research

2015 Annual Report

Objective 1: Develop measures of swine well-being that are science-based and informative under industry conditions and practices; determine the impact of production practices and environmental factors, including climate change, on animal well-being. 1.A. Increase sow longevity by increasing articular cartilage health. 1.B. Decrease perinatal and neonatal piglet mortality. 1.C. Determine factors that influence aggression in pigs. Objective 2: Develop measures of dairy animal well-being that are science-based and informative under industry conditions and practices; determine the impact of production practices and environmental factors, including climate change, on animal well-being. 2.A. Identify a novel indicator of chronic pain in cattle. 2.B. Determine optimum age for grouping, group size, and need for individual partitioning of trough space for group-housed veal and dairy calves. Objective 3: Develop measures of poultry well-being that are science-based and informative under industry conditions and practices; determine the impact of production practices and environmental factors, including climate change, on animal well-being. 3.A. Prevent aggression in poultry by modification of the serotonergic system. 3.B. Develop intervention strategies for increasing heat tolerance in poultry. 3.C. Develop alternative housing for poultry.

The long-term objective of this project is to optimize animal welfare and productivity. The approach is to focus on animal behavior, the outward expression of the cumulative effects of internal biological changes, to assess where challenges may exist and to develop alternative management strategies to solve these challenges. This project will examine animal agricultural practices, using behavior, physiology, immunology, and neurobiology. The project’s focus is on 4 significant areas of concern: aggression, lameness, pain, and discomfort. This unit is charged with the difficult task of conducting research for three species: dairy cattle, swine, and poultry. To accomplish this goal, unit scientists with different expertise work together on multiple and varying projects to address the primary challenges to welfare that are characteristic of the production systems for each species. Our ultimate goal is to: 1) discover and further refine objective measures of stress, and 2) evaluate and create appropriate management and housing methods. A sustained effort is required to make significant progress in optimizing animal welfare.

Progress Report
Decreasing Floor temperature. Prototype cooling pads are being tested for thermal and heat transfer properties, in collaboration with Purdue Agricultural and Biological Engineering Department. Once the preferred prototype is identified, it will be moved to the experimental testing phase on farm. High Tryptophan at Farrowing. The study data collection is complete but video analysis is ongoing. Preliminary data have been analyzed which suggests that High Tryptophan may decrease the number of piglets born dead but not impact crushing deaths. Also, tear stain area is smaller for high tryptophan sows immediately pre-farrowing, indicating lower stress in these sows. Lameness in Sows. Preliminary data has been analyzed which suggest that slowing the growth of sows may reduce osteochondritic lesions, however only 10 sows have been studied. Currently we have an additional 36 sows on study and these will be sacrificed in the next 1.5 years to determine if cartilage health has been improved over the long term. Euthanasia of piglets. Two experiments have been published to show that nitrous oxide (laughing gas) may be a good method to humanely euthanize piglets. A larger study has been initiated which will explore brain wave activity to help determine whether this method sufficiently reduces pain and distress of the process compared to current methods. Lameness in Cows. Cows have been placed on either rubber or concrete, and blood, behavior and lameness data is being collected. This is the beginning of a 2 year project. Group housing of calves. Calves are being housed in pairs and physiologic and behavioral data are being collected to determine how much space is required in between feeders to decrease aggression/competition. Tryptophan and aggression in poultry. The experimental component is complete. Samples have been analyzed and data are currently being analyzed. Supplemental antioxidants and heat stress. Data on the physiology and behavior of hens fed antioxidants has been collected and the experimental component is complete.

1. Tear staining in pigs. Non-invasive indicators of welfare are needed to aid with on-farm welfare assessment. Having previously determined that tear staining amounts were related to stress measures in experimental studies, ARS researchers in West Lafayette, IN together with collaborators at the University of Helsinki, Finland investigated tear staining in pigs housed on farms with different amounts of tail-biting damage and access to different environmental enrichments. Pigs with greater tail damage scores had higher tear staining scores and that tear staining was reduced in pigs with access to multiple environmental enrichment objects. Further validation of this measure will enable producers and auditors to identify pigs with welfare problems at the pen and individual animal level, and thereby carry out timely intervention to address the problem.

2. Heart rate variability in farm animals. There is a need to develop welfare indicators that can be used to infer emotional state in animals. Some measures of heart rate variability are known to reflect positive and negative emotional states in humans. ARS researchers in West Lafayette, IN, together with collaborators at the University of Queensland, Australia and the University of British Columbia, Canada, investigated the use of heart rate variability (HRV) analysis in motion sickness in sheep and pain in dairy cattle. Results indicate that both the up and down (heave) motion and rectal palpation of cows with metritis resulted in changes in heart rate variability measures indicative of motion stress and pain respectively. These results show that HRV can be a tool in in the assessment of negative experiences in farm animals and help identify situations impacting their welfare.

3. Humane euthanasia of piglets. Piglets which are injured or are too weak to nurse must be humanely euthanized; and the current method of blunt force trauma, although humane, is esthetically objectionable to stockpersons and the public. ARS researchers in West Lafayette, IN investigated the use of nitrous oxide (laughing gas) as a more humane alternative to the current method which uses carbon dioxide. Piglets are not aversive to nitrous oxide and that they could be humanely euthanized in a two-step procedure which first uses nitrous oxide which is then followed by exposure to carbon dioxide. Development of this procedure into a workable on-farm method of euthanasia will allow producers to better care for piglets at this critical time.

4. Maternal heat stress in late gestation alters offspring behavior. Calves born to cows that are under a heat event during the last month of gestation have calves that are less thrifty (grow slower and are more prone to disease). ARS researches in West Lafayette, IN applied a heat stress model to late gestation cows and found that calves from the heat stressed dams performed more behavior and had less heaving breathing during heat events than was exhibited by the calves born to control cows. These data indicate that better thermal control of pregnant cows’ environments should be addressed to optimize calf welfare.

5. Perches for laying hens. Osteoporosis is widespread in today’s commercial laying hens and contributes to approximately 20 to 35 % of all mortalities during the egg production cycle of caged hens. Bone fractures during production are a significant welfare issue because of the chronic pain these hens may experience. ARS researchers at West Lafayette, IN found that mechanical loading on bones achieved through perching has beneficial effects on pullet health by stimulating leg muscle deposition and increasing the bone mineral content of certain bones without causing a concomitant decrease in bone mineral density. These results provide evidence that provision of a perch in the hens’ early life has long term benefits to enhance skeletal health and welfare.

Review Publications
Dennis, R.L., McMunn, K.A., Cheng, H., Marchant Forde, J.N., Lay Jr, D.C. 2014. Serotonin’s role in piglet mortality and thriftiness. Journal of Animal Science. 92:4888-4896.
Hester, P.Y., Garner, J.P., Enneking, S.A., Cheng, H., Einstein, M.E. 2014. The effect of perch availability during pullet rearing and egg laying on the behavior of caged White Leghorn hens. Poultry Science. 93(10):2423-2431.
Muir, W.M., Cheng, H., Croney, C. 2014. Methods to address poultry robustness and welfare issues through breeding and associated ethical considerations. Frontiers in Genetics. DOI: 10.3389/fgene.2014.00407.
Hester, P.Y., Al-Ramamneh, D.S., Makagon, M.M., Cheng, H. 2015. Effect of partial comb and wattle trim on pullet behavior and thermoregulation. Poultry Science. 94(5):860-866. doi: 10.3382/ps/pev066.
Mahmoud, U.T., Abdel-Rahman, M.A., Darwish, M.H., Applegate, T.J., Cheng, H. 2015. Behavioral changes and feathering score in heat stressed broiler chickens fed diets containing different levels of propolis. Applied Animal Behaviour Science. 166:98-105. DOI:10.1016/j.applanim.2015.03.003.
Marchant Forde, J.N. 2015. The science of animal behavior and welfare: challenges, opportunities and global perspective. Frontiers in Veterinary Science. 2(16). doi: 10.3389/fvets.2015.00016.
Rault, J., Kells, N., Johnson, C., Dennis, R.L., Sutherland, M., Lay Jr, D.C. 2015. Nitrous oxide as a humane method for piglet euthanasia: behavior and electroencephalography. Physiology and Behavior. 151:29-37. doi:10.1016/j.physbeh.2015.06.026.