Some 6,500 Holsteins are “finished” at this 2,000-acre Ordway, Colo., feedlot, where the growth promotion drug Zilmax is no longer used because it was pulled from the market by its manufacturer.
Credit Peggy Lowe / Harvest Public Media
Moves to limit a specific growth promoter have shaken the cattle industry. Zilmax is a feed additive that most people have never heard of but one that has become a huge -- if controversial -- part of U.S. beef production.
When the drug company Merck Animal Health announced plans to suspend sales of its Zilmax feed additive last week, many observers were shocked.
Yet concern about Zilmax and the class of growth-promotion drugs called beta agonists has been building for some time. In an interesting twist, the decisive pressure on Zilmax did not come from animal welfare groups or government regulators: It emerged from within the beef industry itself, and from academic experts who have long worked as consultants to the industry.