2013 Annual Report
1a.Objectives (from AD-416):
Our primary objective associated with this subordinate project is to determine if live yeast or yeast cell wall supplementation improves the overall health and performance of cattle during the early phases of the feedlot period.
1b.Approach (from AD-416):
Twenty-four recently weaned calves weighing approximately 500 pounds will be transported to our research facility. Upon arrival, all calves will be weighed and placed into one of three treatment groups in a manner that balances the body weights across treatments. The three treatment groups will consist of:.
1)Control group, n = 8 calves, fed a standard receiving diet;.
2)Live Yeast group, n = 8 calves, fed the Control diet containing live yeast; and.
3)Yeast Cell Wall group, n = 8 calves, fed Control diet containing a yeast cell wall product. Calves will be fed their respective diets for 21 days. On day 22, all calves will be fitted with indwelling jugular catheters and probes to measure rectal temperature. On day 23, all calves will be subjected to an immune challenge to determine their innate immune response. Serum samples collected during the study will be analyzed within the Livestock Issues Research Unit for hormones and proinflammatory cytokines associated with the stress and immune response. Additionally, performance data will be collected to determine if the yeast supplements alter performance prior to and after the immune challenge.
The overall focus and objective for this project is to determine if live yeast or yeast cell wall supplementation improves the overall health and performance of cattle during the early phases of the feedlot period. Alternative methodologies that enhance immunity and subsequent health of livestock have the potential to decrease costs associated with medication usage and reduced performance associated with illness, and are consequently in high demand. At the request of the collaborator, the research focus this past year switched from beef cattle to swine. Therefore, a research project was conducted to evaluate the potential benefit of providing a yeast supplement to weaned pigs prior to a Salmonella challenge. Results from this study indicated that yeast supplementation altered the febrile response, the stress response as indicated by cortisol concentrations, white blood cell populations, and metabolic indicators such as glucose and blood urea nitrogen associated with mounting an immune response to Salmonella. While pigs supplemented with the yeast had altered febrile responses, altered metabolic responses, and altered immune cell populations in response to the Salmonella challenge, there were no differences found in fecal shedding of the bacteria.