Year of Publication
Master of Science (MS)
Agriculture, Food and Environment
Animal and Food Sciences
Dr. Eric S. Vanzant
The influence of dietary factors (including endophyte exposure, phytogenic supplementation, and controlled feeding) on relationships between exit velocity (EV), growth performance in grazing and finishing cattle, and carcass characteristics were explored. Two grazing studies were conducted evaluating EV effects on cattle grazing both toxic and nontoxic endophyte-infected tall fescue. Cattle were followed through two subsequent finishing studies and an additional beef cattle finishing beef cattle study was also conducted. Results from these studies agree with many literature reports indicating that EV measures relate to growth performance and associated carcass traits in beef cattle being fed high energy diets in confinement, but also indicated that a high degree of acclimation to handling prior to EV determination can erode the value of EV as a predictor of finishing performance. Relationships between EV and ADG under grazing conditions were weaker and less predictable. Prior handling and acclimation to facilities may influence ability to accurately measure relationships between EV and growth performance. Large difference in grazing ADG, induced by differences in exposure to endophytic alkaloids, did not alter the relationship between EV and ADG during finishing. Grazing toxic vs. non-toxic tall fescue showed potential to influence the response to dietary supplementation with a commercial phytogenic additive. Additionally, determining proper components, mode of action, proper dosage, and all potential effects of phytogenic supplementation on beef cattle is needed before consideration as either complements or replacements to antibiotics. Finally, utilizing controlled feeding may be beneficial for testing particular hypotheses but economic benefit is questionable when considering loss in overall hot carcass weight.
Digital Object Identifier (DOI)
Shanks, Paul, "INFLUENCE OF DIETARY MANIPULATION ON THE RELATIONSHIP BETWEEN TEMPERAMENT MEASURES AND GROWTH IN BEEF CATTLE: ENDOPHYTE EXPOSURE, PHYTOGENIC SUPPLEMENTATION, AND CONTROLLED FEEDING" (2021). Theses and Dissertations--Animal and Food Sciences. 131.