Location: Livestock Issues Research2012 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:
Livestock Issues Research Unit scientists conducted five studies associated with the project objectives during FY12. For Sub-objective 1B, three final studies were conducted to evaluate non-antibiotic supplements as a means to enhance health and performance in beef cattle. The first study evaluated the health and performance benefits of adding citrus pulp in the diets of cattle. Results demonstrated that including citrus pulp in the diet can alter the physiological and acute phase response of newly received feedlot heifers to an immune challenge. However, inclusion of citrus pulp at levels of 10% or greater may hinder feedlot performance. The second study evaluated the inclusion of yeast cell wall in the diet of feedlot heifers. Results revealed that adding yeast cell wall in the diet of feedlot heifers reduced the negative effects associated with an immune challenge, and enhanced energy metabolism during the immune challenge. Addition of yeast cell wall to the diet also appeared to enhance performance, especially during periods of heat stress. The third study evaluated a commercially available feed additive (i.e., OmniGen-AF) typically used to treat hemorrhagic bowel syndrome in dairy cattle as a potential immune enhancer in beef calves. Results indicated that OmniGen-AF primed the immune system of the calves in a manner that expedited the recovery from an immune challenge. The data also indicated that OmniGen-AF altered the metabolic response during the immune challenge by increasing available glucose and reducing the need to mobilize energy via tissue breakdown. These studies, coupled with our previous research, conclusively demonstrate that providing non-antibiotic alternatives to high-risk feedlot cattle can improve performance, health, and overall well-being. All data have been analyzed for these studies, results have been presented at scientific meetings, and manuscripts are being prepared for publication. For Objective 2, two final studies were conducted evaluating the influence of transportation on the feeding behavior of newly weaned beef calves and the influence of gestational stress on subsequent offspring. The major finding from the first study was that transportation duration, 6 versus 24 hours, did not affect the amount of time it took for calves to consume enough feed to meet net energy for maintenance requirements. In the second study, the influence of gestational stress on performance, health, and well-being of beef calves was studied. All calves in this study have been born, and researchers have collected birth weights, gestation lengths, and blood samples within 24 hours of birth. Data will be collected from these calves until weaning, at which time researchers will evaluate the influence of gestational stress on growth, immune system function, and other endocrine parameters. Preliminary results reveal that pregnant cows partially acclimate to repeated stressors, and that animal temperament and the transportation process influence the physiological responses to stress. Final data on the calves, an essential data set with regard to the development of specific management practices for cattle, will be collected in FY13.
Schwertner, L., Galyean, M., Hulbert, L.E., Carroll, J.A., Ballou, M. 2011. Effects of dietary source and intake of energy on immune competence and the response to an infectious bovine rhinotracheitis virus (IBRV) challenge in cattle. Livestock Science. 141(2-3):259-266.