Merck Animal Health has decided to stop selling its cattle feed additive Zilmax in the US and Canada, while it studies a possible link between Zilmax and poor health in cattle.
Zilmax became the focus of attention in the livestock industry after Tyson Foods said that it will stop buying Zilmax-fed cattle for slaughter beginning September. Tyson, the biggest US meat processor, said it was concerned about Zilmax potentially causing health problems for some cattle. Merck defended Zilmax but promised a research project to determine if the concerns were valid. (view original article).
Merck said stopping sales will allow it to set up a study protocol and follow certain cattle to find out possible causes of lameness and other mobility problems. The company also plans to review other possible factors like nutrition and transportation of the cattle.
Zilmax is mixed into food and is used to bulk up cattle before slaughter. It has been on the market in the US since 2007 and is one of two supplements approved for that purpose. The products can help feedyards get roughly 25 more pounds of beef from each carcass. They’ve been increasingly used to offset dwindling cattle herd numbers, particularly in the face of last year’s drought. Zilmax is the more potent of the two, and requires a three-day withdrawal period before slaughter.
While markets such as China and the EU have banned imports of meats raised with beta-agonists, in the US, more than 70% of US beef cattle that go to slaughter do so after consuming a regimen of beta-agonist drugs, according to industry estimates. The FDA has deemed beta-agonists safe both for farm animals and human health, and there has not been a suggestion by regulators or industry that food safety is in question.
Some cattle feeders who formerly used Zilmax said they are frustrated that they are having trouble ordering an alternative. For many, the drugs have been a way to reduce some of the economic pain caused by high costs for grain fed to cattle.
Merck has said no safety issues have been discovered in 30 studies since Zilmax was introduced in the United States in 2007.
Merck sold US$159 million worth of Zilmax in the US and Canada last year.