Location: Livestock Issues Research2011 Annual Report
1a. Objectives (from AD-416)
The objective of the research associated with this Specific Cooperative Agreement is to evaluate the potential influence of cattle temperament, transportation, and disease challenge on the productivity and overall well-being of cattle during critical stages of the production cycle. The research will include, but not be limited to, evaluating the potential influence of temperament, transportation, and disease challenge on regulation of the growth, stress, and immune systems of cattle and production efficiency following these stressors. The critical stages of the production cycle to be studied involve the movement of cattle through the production system as cattle are moved from the ranch to a stocker location and again to the finishing feedlot.
1b. Approach (from AD-416)
Calves will be selected based on an assigned temperament score measured at weaning. Temperament score will be calculated based upon an average of exit velocity (EV) and pen score (PS). Exit velocity is an objective measurement that records the rate (m/s) at which cattle exit a working chute. Pen score is a subjective measurement based upon an animal's reactivity to a human entering the pen. Following temperament classification, calves will be subjected to various management practices, such as transportation and a simulated disease challenge, which are known to cause stress in livestock and have negative impacts on health, productivity, and well-being. Animal health and productivity will be monitored prior to and following these stressors to determine if an animal's temperament is associated with, or predictive of, how that animal copes with and recovers from the particular stress. A large-scale study will be implemented where yearling heifers that had been evaluated for temperament will be selected using the 32 calmest and 32 most temperamental from a population of over 125 heifers in a single calf crop. These heifers will be further stratified equally into equal subsets of 16 calm and 16 temperamental animals which will be transported for a 12-hour period followed with an overnight rest and then transported again for 12 hours back to the point of origin. The remaining subsets of 16 calm and 16 temperamental heifers will remain at the point of origin and not receive any transportation stressor. After return to the point of origin each subset of 16 heifers will be divided equally into subsets of 8 animals with one subset of 8 receiving an LPS challenge to simulate disease and the remaining subset will not be challenged to simulate the lack of disease stress. The animals will be then placed in Grow Safe equipped feeding facilities and feed consumption will be monitored for a 2-week recovery period followed by a 70-day feeding and growth period to calculate residual feed intake in these animals as well as all standard measurements of feed efficiency and growth. The heifers will be weighed at the beginning of the study and at each point of transportation and challenge, and body weights will be collected at 7-day intervals throughout the feeding period. Blood samples will be collected for endocrine and immune function measurements appropriately throughout the experimental period. These data should allow for determination of the economic losses due to transportation, temperament, and disease challenge. The involvement of the cytokines and mRNA for the cytokines will allow for better basic understanding of immune function following stressors in yearling beef females. Further small-scale studies will be designed following the large-scale study to further examine basic endocrine and immune function in stressed beef animals.
3. Progress Report
The overall focus and objective for this project is to evaluate potential influences of temperament, transportation, and disease challenge on the health, productivity, and overall well-being of yearling cattle. Significant progress was made on this project during the past year with regard to the effects of transportation and disease challenge. Specifically, a series of experiments was conducted to examine the effects of transportation and a simulated disease challenge on feed intake, feeding behavior, and productivity of weaned calves. Results from these studies indicated that there is considerable variation in post-weaning feeding behavior in cattle, some of which is attributable directly to breed. These studies also revealed that the decrease in body weight following transportation primarily reflects feed and water withdrawal. Additionally, these studies revealed that utilizing automated feeding systems to monitor feed intake post-weaning can contribute to variations in feed intake, as some cattle are more resistant to utilizing these systems. Finally, results from these studies indicate that handling and loading cattle causes a transient elevation in body temperature, but transportation of cattle does not appear to exacerbate the febrile response associated with an immune challenge post-transport. Thus, contrary to popular opinion, transportation in and of itself does not appear to negatively impact the health, productivity, and overall well-being of yearling cattle. Results from these collaborative efforts were presented at scientific meetings during this fiscal year and manuscripts were prepared and submitted to peer-reviewed scientific journals. The ADODR maintained regular contact with the cooperator via telephone calls, e-mails, and face-to-face meetings to review progress of the research and to verify appropriate use of funds.