Location: Livestock Behavior Research2017 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.
This is the final report for this project. During the past 5 years significant progress has been made in advancing the objectives as laid out in the original plan. Under Objective 1, it was discovered that restricting the growth of sows in efforts to decrease lameness was not effective and that alternative strategies must be sought. Decreasing the floor temperature under the sow during lactation did prove to be an effective method to reduce her heat load, and alter her physiology and behavior to indicate improved thermal comfort. In contrast, methods to increase the amount of energy piglets have to produce heat and maintain thermal comfort were not successful, thus leading to other research to use environmental manipulations to ensure piglet thermal comfort. Similarly, increasing dietary tryptophan for the sow around farrowing did not impact behavior or neonatal mortality, but may decrease stillbirths, which would need further investigation to be confirmed. Under Objective 2, it was discovered that leukocytes from cows on rubber flooring were altered in phenotype and function, suggesting the link between chronic pain conditions and susceptibility to disease. Calf group housing projects determined that of 2, 4, or 8 in a group that 4 was optimum for social and health indices. The age of grouping neonatal dairy calves was not detrimental to social interactions and disease incidents even at 3 days of age. However, early grouping (3 days) was more difficult for the feeding routine (getting all calves to their bottles) for one week. Under Objective 3, it was discovered that dietary tryptophan supplementation reduces feather pecking and aggression in laying hens. This provides a useful management tool to increase productivity and hen welfare. To address heat stress concerns in poultry, research found that an antioxidant can be used as a management strategy for reducing heat stress effects in laying hens. It was discovered that providing perches, especially during the pullet phase, reduces leg bone fracture incidence, and inhibits anxiety response in laying hens. However, perching does not reduce keel bone damage.
1. Sow cooling over lactation. In summer, farrowing sows are often exposed to temperatures above their upper critical temperature. This heat stress can affect sow welfare and productivity and have economic impact. Cooling the room is not an option as piglets need high temperatures. ARS researchers in West Lafayette, Indiana, collaboration with Purdue University designed a water-cooled floor pad that is placed under the sow. When exposed to acute heat stress, the pad successfully reduced sow body temperature, heart rate and respiration rate, and reduced posture-changes and drinking behavior, all indicating greater sow comfort. These results indicate improved sow welfare and will have production benefits in maintaining sow feed intake and milk production and decreasing risk of piglet crushing.
2. Development of a tool to more accurately predict estrus in pigs. Accurate estrus detection can improve sow conception rates and increase swine production efficiency. Unfortunately, current practices based on individual animal behavior may be inefficient due to large sow populations at commercial farms and the associated labor required. ARS researchers in West Lafayette, Indiana determined that at the onset of estrus in sows, body temperature was reduced and activity was increased. These data may provide initial physiological and behavioral markers of estrus in sows that can be used in the development of a precision livestock management tool that will help producers more accurately predict estrus in their sow herd.
3. Feasibility of using a conveyor belt to load piglets. Piglets are not accustomed to climbing sloped ramps; however, sloped ramps are impossible to avoid in regular management and handling practices due to design of the physical facilities and the vehicles used to transport animals. Intense handling that may occur when there is not self-movement of pigs causes strain on animal handlers and can create a welfare problem for the pigs in question. ARS researchers at West Lafayette, Indiana found that weaning and nursery aged piglets could be easily loaded to a height of 8 feet using a mechanical conveyor that would take them to the top without them having to walk the steep angle. These findings can be used to develop automated handling methods to decrease the stress to which piglets are exposed.
4. Tryptophan and piglet mortality. Piglet mortality remains a serious welfare and economic problem. Much of the early mortality is due to crushing by the sow. Tryptophan has been shown to reduce aggression and have a calming effect on behavior, which may reduce the number and type of posture changes, thereby altering risk of crushing. ARS researchers at West Lafayette, Indiana found that feeding high levels of tryptophan to sows just prior to farrowing did not affect posture-changing behavior or liveborn mortality. There may be a beneficial effect on stillbirth incidence and farrowing day feed intake, which could affect early lactation milk production. This requires further investigation but may improve overall piglet production and growth.
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