Zipaterol Supplementation Improved Indicators of Well-Being, but not Growth in Heat-Stressed Red Angus Steers

Authors

Pablo C. Grijalva
Duarte E. Diaz, University of Arizona
Samuel R. Garcia, University of Arizona
Ty B. Schmidt, University of Nebraska-LincolnFollow
Jessica Lynn Petersen, University of Nebraska - LincolnFollow
Dustin T. Yates, University of Nebraska LincolnFollow

Date of this Version

2022

Citation

2022 Nebraska Beef Cattle Report

UNL Beef, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln

Abstract

The effects of zilpaterol (β2 agonist) supplementation on respiration rate, body temperature, growth, and carcass traits were studied in chronically heat-stressed feedlot steers. Through a collaborative partnership with the University of Arizona, Red Angus steers were heat stressed (90-105^oF) and fed zilpaterol-supplemented rations (Thermo-neutral control steers were pair-fed to the average feed intake of heat-stressed steers) for 30 days. Hot and cold carcass weights for heat-stressed cattle were 3% less than for controls, despite equal feed intake. Zilpaterol did not affect growth but improved the heat stress-induced hyperventilation and elevated body temperatures. Lighter carcass weights in heat-stressed cattle show that factors other than nutrient intake hinder growth under heat stress. Contrary to previous anecdotal reports, this study found no evidence that zilpaterol supplementation worsened the effects of heat stress. In fact, respiration rates and body temperatures show that zilpaterol moderates some responses to chronic heat stress in cattle.