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United States Department of Agriculture

Agricultural Research Service


Location: Livestock Behavior Research

2010 Annual Report

4. Accomplishments
1. Infrared beak trimming improves hen welfare. Beak trimming, using a hot blade, is a common practice in the poultry industry that is often criticized as inhumane. ARS researchers at West Lafayette, IN investigated an alternative method of beak trimming which uses an infrared laser, similar to those used in biomedical procedures. They used both treatments and studied 60 production hens from 5 to 35 weeks of age. Hens which were beak-trimmed using the infrared laser method showed an improvement in performance and a reduction in stress levels. These results suggest that the infrared beak treatment provides a more welfare friendly means of beak trimming, allowing birds to display more efficient feeding behavior with less morphological abnormalities of the beak stumps. This study provides scientific evidence to support the use of infrared beak-trimming by producers and addresses the welfare concern of the current practice.

2. Genetic variation can help poultry to combat heat stress. Heat stress is a major problem experienced by poultry during high-temperature conditions. The ability to manage the detrimental effects can be attributed to many factors, including genetics. ARS researchers in West Lafayette, IN studied two different genetic lines of poultry to determine their ability to cope with heat. The two strains tested differed in their ability to cope with heat, with one strain showing more panting and behavioral modifications aimed at reducing their heat load. The data suggest that heat stress has detrimental effects on the physiology of laying hens; however, differences were observed in the heat stress response due to the genetic basis of variation. These results provide evidence that will be valuable for determining interventions for laying hens under heat stress conditions.

3. Heart rate variability frequency bands have been defined which provide a measure of positive and negative stress. The causal neurophysiological processes that mediate behavioral and physiological reactivity to an environment have largely been ignored. Heart rate variability analysis is a clinical diagnostic tool used to assess affective states (stressful and pleasant) in humans, but its application is very limited in farm animals. ARS scientists in West Lafayette, IN conducted an experiment to define the low frequency and high frequency components of heart rate in swine using pharmacologic blockade. They successfully define both the low and high frequency bands which are measures of negative and positive states, respectively. This will allow future research to use heart rate variability analysis in assessing the welfare state of swine.

4. Understanding aggression when sows are mixed in indoor and outdoor housing systems. ARS researchers in West Lafayette, IN, identified important behavioral sequences when unacquainted sows meet in limited and unlimited space. Unacquainted sows fight when introduced to each other but their detailed behavior during introduction has not been studied to determine whether escalation of their behavior into aggression can be predicted from behavioral sequences. We found that certain behaviors such as nose-to-nose contact decreases subsequent risk of aggression, whereas others, such as ignoring social contact, increases subsequent risk of aggression, particularly in indoor pens. Indoors, sows engage in steadily escalating aggressive behaviors over time and display more pushes, knocks, and bites than sows being mixed outdoors in more space. However, outdoor sows are quicker to initiate high intensity aggression without the steady escalation seen indoors. Although biting occurs more quickly outdoors, the total number of bites delivered and the number of bites per interaction are lower than seen indoors. These differences in strategy are most likely due to the amount of space in the different situations. Indoors, sows cannot get away from each other after a fight has taken place, and therefore before engaging in a fight, they probably use low intensity interactions to obtain information about their chances of winning a fight. Outdoors, the space available for escape means that a loss can be immediately followed by withdrawal and avoidance. Aggression at mixing is a major issue for the US swine industry as it moves towards group housing of sows. Our results improve our understanding of what causes aggression to escalate and will help in the design of methods that will promote the ‘positive’ behaviors before mixing, thereby reducing the aggression.

Review Publications
Marchant Forde, J.N., Pajor, E.A. 2009. Welfare of Gestating Sows. In: Marchant-Forde, J.N., editor. The Welfare of Pigs. Dordrecht, The Netherlands:Springer Science + Business Media B.V. p. 95-140.

Cheng, H. 2010. Breeding of Tomorrow’s Chickens to Improve Well-Being. Poultry Science. 89(4):805-813.

Pohle, K., Cheng, H. 2009. Furnished Cage System and Hen Well-Being: Comparative Effects of Furnished and Battery Cages on Egg Production and Physiological Parameters of White Leghorn Hens. Poultry Science. 88(8):1559-1564.

Poletto, R., Meisel, R.L., Richert, B.T., Cheng, H., Marchant Forde, J.N. 2010. Aggression in Replacement Grower and Finisher Gilts Fed a High-Tryptophan Diet and the Effect of Long-Term Human-Animal Interaction. Applied Animal Behaviour Science. 122(24):90-110.

Horn, M.J., Van Emon, M.L., Gunn, P.J., Eicher, S.D., Lemenager, R.P., Pyatt, N., Lake, S.L. 2010. The Effects of Maternal Natural (RRR Alpha-Tocopherol Acetate) or Synthetic (All-Rac Alpha-Tocopherol Acetate) Vitamin E Supplementation on Suckling Calf Performance, Colostrum IgG, and Immune Function. Journal of Animal Science. 88:3128-3135.

Bewley, J.M., Boehlje, M.D., Gray, A.W., Hogeveen, H., Kenyon, S.J., Eicher, S.D., Schutz, M.M. 2010. Assessing the Potential Value for an Automated Body Condition Scoring System through Stochastic Simulation. Agricultural Finance Review. 70(1):126-150.

Bewley, J.M., Boehlje, M.D., Gray, A.W., Hogeveen, H., Kenyon, S.J., Eicher, S.D., Schutz, M.M. 2010. Stochastic Simulation using @Risk for Dairy Business Investment Decisions. Agricultural Finance Review. 70(1):97-125.

Last Modified: 2/23/2016
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