Location: Livestock Issues Research2013 Annual Report
1a. Objectives (from AD-416):
The long-term objective of this project is to enhance animal well-being and performance in swine and beef industry production environments. Over the next 5 years we will focus on the following objectives: Objective 1: Identify non-antibiotic nutritional supplements that support and/or enhance immune function in weaned pigs and incoming feedlot cattle. Objective 2: Determine the relationships among animal temperament, stress responsiveness, and immune function in cattle as related to livestock management practices, such as weaning and transportation, and utilize this information to develop alternative management practices that enhance immunity, productivity, and overall well-being.
1b. Approach (from AD-416):
Our research will focus on enhancing the performance, health, and overall well-being of beef cattle and swine in production environments. For the swine studies in Objective 1, several experiments will be conducted to evaluate various parameters associated with the health and productivity of swine following dietary inclusion of various nutritional supplements that have the potential to enhance innate immunity. Blood samples will be collected for analysis of hormones associated with the stress response, as well as hormones associated with the proinflammatory response following an endotoxin challenge. For cattle studies in Objective 1, calves will be weaned at approximately 6 months of age and fed various non-antibiotic products as potential modulators of immunity. Calves will be provided either a medicated diet or a non-medicated concentrate ration containing a non-antibiotic supplement for 21 days. Calves will be either inoculated with infectious bovine rhinotracheitis virus (IBRV) to determine if the non-antibiotic supplements provided any immunological protection to a viral challenge, or exposed to endotoxin to evaluate whether or not these non-antibiotic supplements enhance innate immunity. Feed intake and body weight will be routine measurements. Blood samples will be collected for analysis of hormones associated with the stress response, the growth axis, as well as cytokines and acute phase proteins associated with the immune response. For Objective 2, the research will focus on determining the relationships among animal temperament, stress responsiveness, and immune function in cattle as they relate to livestock management practices such as weaning and transportation. This information will be used to develop alternative management practices that enhance immunity, productivity, and overall well-being. Initial studies will determine the effect of animal temperament on the innate immune response following an endotoxin challenge. Subsequent studies will evaluate the effect of temperament on the response to management practices such as transportation. We will also evaluate the effects of weaning strategies on the innate immune system of beef calves. In these studies, weaning-age calves from a single breed will be categorized as to their temperament (temperamental or calm) based upon an objective exit velocity (EV) scoring system. Exit velocities will be obtained by determining the rate at which calves exit the working chute and traverse a fixed distance (1.83 m). In the first studies, we will assess the innate immune response to an endotoxin challenge based upon temperament. Blood samples will be collected and serum analyzed for hormones associated with the stress response, as well as cytokines associated with the acute phase immune response following the endotoxin challenge. In the subsequent studies, we will assess the stress responsiveness following management practices such as transportation and weaning. Body weights, blood samples, and rectal temperatures will be routine parameters measured for these studies. Blood samples will be analyzed for stress hormones, as well as cytokines associated with the immune response.
3. Progress Report:
This will serve as the final report for this project, as it was replaced with the 6208-32000-007-00D project within the Livestock Issues Research Unit during FY2013. Major accomplishments by ARS and collaborating scientists throughout the life of this project included: 1) Development of in-dwelling vaginal and rectal temperature monitoring devices that have allowed for continuous measurements of body temperature responses to various stressful events in research and production settings; 2) Demonstrating that cattle temperament can significantly influence the stress, innate immune, and metabolic responses of cattle when exposed to an immune challenge; 3) Demonstrating that early weaning of beef calves can alter the innate immune response to an endotoxin challenge; 4) Proving the existence of sexually dimorphic stress and immune responses in cattle; 5) Demonstrating the existence of breed effects within Bos taurus associated with the stress and innate immune responses of cattle during thermoneutral and heat stress conditions; 6) Proving that transportation in and of itself is not stressful to cattle and that the main stress associated with relocating cattle is associated with the handling and loading of cattle; 7) Demonstrating that various nutritional supplements such as chromium, live yeast, and yeast cell wall products when fed to swine and cattle can significantly improve health, performance, and the ability to tolerate heat stress events; 8) Providing evidence that citrus by-products may be a valuable tool for suppressing chronic and acute pathogenic challenges in livestock, and perhaps eliminating pathogen shedding prior to harvest; 9) Providing evidence that an animal's metabolism may drive the overall immune response during an immunological insult; and 10) Demonstrating that prenatal stress imposed by exposing pregnant cattle to multiple relocation events can have epigenetic effects that alter the offspring's stress responsiveness, innate immune system, and even the temperament of the offspring. Collectively, these findings provide significant information pertaining to the need for the development of alternative management practices within the livestock industry, and well as aiding in the understanding and knowledge base regarding biological variations that exist among individuals within given animal populations. This information will be a significant resource as progress continues to improve the overall health, performance and well-being of livestock, and will possibly aid in efforts to reduce foodborne illness stemming from livestock production.
Bernhard, B.C., Sanchez, N.C., Rathmann, R.J., Carroll, J.A., Finck, D.N., Jennings, M.A., Young, T.R., Johnson, B.J. 2012. Chromium supplementation alters both glucose and lipid metabolism in feedlot cattle during the receiving period. Journal of Animal Science. 90:4857-4865.