Zilpaterol hydrochloride, or Zilmax®, is a beta-agonist approved to be fed to finishing cattle the last 21 days of the feeding period. Researchers wanted to determine if feeding Zilmax to finishing cattle affected response to heat stress, mobility and body temperature, performance, or carcass characteristics when fed in the open or in shaded pens.
Source: Drovers CattleNetwork, June 15, 2016.
The effect of shade had no significant effect on body temperature or performance for cattle fed Zilmax or in the control group. Zilmax-fed cattle had heavier carcasses, larger ribeyes, and decreased yield grades compared to the cattle not fed Zilmax. Zilmax-fed cattle did have increased respiration rates but no adverse effects on body temperature or mobility were reported.
INSIGHTS: There is a three-day withdrawal for this feed additive, so careful management is necessary for responsible use of this technology.