2013 Annual Report
1a.Objectives (from AD-416):
For growing meat animals, identify physiological responses to stress that contribute to production loss and disease susceptibility; develop environmental and animal-specific risk assessments of stress as management guides to alert producers and improve animal well-being; develop precision animal management strategies to ameliorate heat stress effects; and develop ventilation design standards for contemporary swine production systems.
1b.Approach (from AD-416):
This project incorporates components of two former research projects on management of livestock stress and genetic factors related to disease susceptibility. Stress response evaluation utilizes physiological (respiration rate, health status, etc.), physical (body temperature, coat color, etc.), and behavioral (temperament, eating, etc.) measurements to characterize the impact of stress (particularly environmental) on feedlot cattle. These measurements will be refined to provide dynamic response evaluations in a feedlot setting, both for data collection and as potential management tools. The results will provide risk assessment models to assist producers in identification of animals that would most benefit from changes in management (shade, sprinklers, etc.). In addition, weather data will be utilized to provide advanced warnings to producers of impending environmentally stressful conditions to cattle. Genetic diversity for stress traits among several breeds will be characterized to identify breed differences and suggest management alternatives based on genotype. Also, criteria of ventilation requirements for swine production will be updated for modern lean high growth rate animals and ration formulations. Livestock will be observed in production feedlot settings or in controlled environment chambers to provide suitable environmental and management control. The feedlot includes modern animal handling facilities to individually manage cattle or provide group penning of cattle with or without shade. Environmental chambers provide precision control of environmental factors (temperature, humidity, and light) in close proximity of calorimeter equipment to measure energy expenditure of livestock. The availability of a wide range of cattle breeds, extensive animal handling and technical expertise, and animal health practitioners provides the necessary resources for conducting basic and applied research.
Bridging project #5438-32630-006-00D was put in place after 5438-32630-005-00D expired in FY 2012. The new replacement project plan is scheduled for OSQR peer review in June 2014.
A feeding system for use in a commercial-sized pen, was designed to record individual animal’s presence at the feeder. The system recorded information using radio-frequency identification (RFID) technology and a series of multiplexers. It was determined that finishing pigs increase the time spent at the feeder from the day the pigs enter the facility until plateauing at approximately day 40. This individual animal data has shown not only differences in feeding behavior between barrows and gilts and fast growing and slow growing animals, but most importantly has shown promise in detecting sick animals. While more work needs to be completed, this initial research demonstrates the potential of utilizing feeding behavior or time spent eating as a method of animal management.
A study to evaluate using surface temperatures of swine as a method of determining heat tolerance was completed. Both individual and groups of animals were used in the analysis. Surface temperatures were significantly affected by ambient temperature and response equations were developed. Breakpoint analysis revealed a threshold, thought to equate to the maximum value of the thermal neutral zone, ranging between 17.4°C and 23.2°C. It was concluded that thermal images could be successfully used to evaluate the thermal needs of pigs and further experiments need to be conducted to validate thresholds.
Based on previously conducted and reported research, a shade structure was designed and built for commercial sized pens. This structure is currently being tested for durability and effectiveness as a management option for heat stress in feedlots.
An analysis was developed and completed to assess individual animal responsiveness, based on breathing rate, to heat stress. This analysis revealed the varied responses from cattle with different coat colors and cattle with and without access to shade. It was determined that color/breed plays an important role in heat stress, but not all colors/breeds of cattle benefit from having access to shade. Further studies need to be completed to investigate the use of this analysis method with different stress measurements.
Development of a new shade structure for commercial sized lots. Shade has a positive effect on reducing stress in feedlot cattle but implementation is limited due to cost and maintenance issues. Different shading materials range in price and effectiveness with each material having its own set of benefits and challenges. Initial instrumentation tests conducted by ARS researchers at Clay Center, NE, determined that even a minimal shade will offer enough protection to reduce the thermal index one category (emergency to danger–danger to alert). Animal tests using 3 of the different types of shade (100% shade cloth, 60% shade cloth, and snow fence) were completed during the summer of 2010. Initial analysis showed that all material were effective in reducing respiration rates and associated heat stress. A shade structure was designed according to the following criteria: cost, effectiveness, durability, low maintenance, and minimal interference with normal feedlot management. The design integrates animal/shade response data collected over the last decade. Eight 10 m tall by 15.4 m long structures were installed at the USMARC feedlot in Clay Center, Nebraska. The north/south structures were fitted with four 15.4 m lengths of poly snow-fence. These structures provide an effective 50% shade coverage that tracks the sun during the day and offers up to 3 m2 of shade per head.
Brown Brandl, T.M., Rohrer, G.A., Eigenberg, R.A. 2013. Analysis of feeding behavior of group housed growing-finishing pigs. Computers and Electronics in Agriculture. 96:246–252. Online available: http://dx.doi.org/10.1016/j.compag.2013.06.002.
Brown Brandl, T.M. 2013. Managing thermal stress in feedlot cattle: environment, animal susceptibility and management options from a U.S. perspective. In: Aland, A. and Banhazi, T., editors. Livestock Housing: Modern Management to Ensure Optimal Health and Welfare of Farm Animals. Wageningen, The Netherlands: Academic Publishers. Pages 189-208.
Brown Brandl, T.M., Eigenberg, R.A., Purswell, J.L. 2013. Using thermal imaging as a method of investigating thermal thresholds in finishing pigs. Biosystems Engineering. 114:327-333.