A study of 20 heifers found “no noticeable detrimental effect on cattle health or well-being” from the feed supplement Zilmax to promote weight gain, says the University of Nebraska. Its researchers joined USDA scientists for the 26-day study. Drug maker Merck withdrew Zilmax from the market last year after reports of cattle appearing lame or having difficulty in standing.
Livestock feeders have switched to other supplements from the beta-agonist class. Merck wants to demonstrate that Zilmax is safe by testing it in 250,000 cattle in a randomized, controlled study but finds resistance from cattle feeders, says the newsletter Fierce Pharma, citing a Wall Street Journal story.