Zilmax, produced by Merck Animal Health, is feed supplement approved by the U.S. Food and Drug Administration and given to cattle to improve feed conversion, resulting in more beef from each animal harvested. Given a situation where the U.S. cattle herd is at its lowest number since 1952, maximizing the yield from each animal is important.
Zilmax is part of a class of growth-promotants known as beta-agonists. It was approved for use in 2006 and debuted in the U.S. in 2007. Cargill was the last major beef packer to allow cattle fed Zilmax into its beef supply chain, in June 2012. Cargill studied Zilmax for years prior to doing so. One reason Cargill was initially reluctant to accept cattle fed Zilmax was a series of extensive beef tenderness tests that created concern about potential impact to product quality. During the years from 2006 to 2012, best practices were developed by the company’s cattle procurement and Research & Development teams to ensure product quality.
By 2012, an estimated 70 to 80 percent of the U.S. cattle herd was being fed Zilmax or Optaflexx. The latter is a similar growth promotant produced by Elanco that had been in use for nearly a decade. With such a high percent of cattle being fed beta-agonists, combined with a drought-depleted U.S. cattle herd, Cargill Beef determined that, when employing best practices, the business would accept Zilmax-fed cattle. Of the major U.S. packers, Cargill harvests the lowest percentage of cattle fed Zilmax.
In early August 2013, animal well-being issues potentially linked to Zilmax surfaced at a National Cattlemen’s Beef Association (NCBA) meeting. Multiple packers referenced situations that they believed may have been linked to Zilmax, although no scientific studies had made such a connection. Dr. Temple Grandin, the world-renowned animal welfare expert, was present and expressed concerns. While Cargill has not linked Zilmax to any specific incidents involving animal well-being, the company does believe more research is necessary to answer recently raised questions regarding the use of this product.
Consequently, Cargill supports Merck’s decision to suspend sales of Zilmax in the U.S. and Canada. The last of the cattle currently being fed Zilmax that are in Cargill’s supply chain will be harvested by the end of September. Cargill will be suspending purchase of Zilmax-fed cattle in North America, pending research being conducted by Merck. This will give producers adequate time to transition cattle currently being treated with Zilmax.
Cargill believes Merck’s decision to suspend sales of Zilmax until additional research can be conducted is prudent. Consequently, Merck has reached out to the industry and one of the steps it is taking involves the creation of an advisory board. Dr. Mike Siemens, Cargill’s head of animal welfare and husbandry, will represent Cargill on that board.
There are no food safety issues associated with Zilmax or this decision. Meat from cattle treated with Zilmax is safe to eat. Instead, this decision is linked to Cargill’s commitment to ensure the welfare of cattle harvested in the industry.