Posted August 21, 2013
The Food and Drug Administration (FDA) will work with Merck & Co. and the USDA to gather information and review a cattle feed additive, Zilmax, to determine if the product is unsafe, according to a Reuters story, available here. 
Recently, Tyson Foods, Inc. announced that it would stop accepting beef from Zilmax-fed cattle “after it observed animals arriving at its slaughter facilities with signs that they had difficulty walking or moving.”  According to a Beef Magazine article, available here, a letter from Tyson addressed to cattle feeders stated that some health experts suggested “the use of the feed supplement Zilmax, also known as zilpaterol is one possible cause.”  As an “interim measure” Tyson will not purchase cattle fed with Zilmax after Sept. 6.  The company further stated that this “is not a food safety issue.  It is about animal well-being and ensuring the proper treatment of the livestock we depend on to operate.”
Merck released a statement highlighting animal well-being as a priority for the company, stating that the “benefits and safety of Zilmax are well documented” and that “Zilmax has a 30+ year history of research and development and rigorous testing.”

Merck announced that it would temporarily suspend sales of Zilmax in the U.S. and Canada and “revealed a new program to retrain and certify beef producers in administering Zilmax, which had sales of $159 million last year” according to the Reuters article.  Zilmax was approved by the FDA in 2006 and “is one drug in the class of beta-agonists, which is approved and deemed safe by the FDA and long used in the livestock industry to add muscle weight to cattle, pigs, and turkey in the weeks before slaughter.”

According to another article by Beef Magazine, live “cattle futures surged on the news, as traders anticipated less beef volume in the coming months.”  Cargill, National Beef and JBS announced that they would not follow Tyson’s decision and would continue to accept cattle fed with Zilmax.  Glynn Tonsor, Kansas State University economist, said that this announcement might “take some of the heat off of the beef tonnage concerns that rocked traders earlier, but the situation is fluid” and “nothing guarantees that Cargill, National, and JBS won’t change their policies down the road, or that Tyson will change its policy, for that matter.”