Last week Tyson Foods sent a letter to cattle feeders saying that as of September 6th it will not be accepting any cattle fed the growth enhancer Zilmax, an FDA-approved supplement for cattle that increases gain and feed efficiency in the production of beef. Tyson cites that the reason for their decision lies in an “unknown factor” behind the recent instances of cattle delivered for processing that have difficulty walking. They state in the letter that while they don’t know that Zilmax is the cause of these problems, it has been suggested to them that it “might be”. Tyson also stressed that “this is not a food safety issue”. In other words it is an animal welfare issue. In response, the president of the National Cattlemen’s Beef Association says that the NCBA stands behind beta-agonist science, but the group also respects Tyson’s decision not to accept those cattle, and takes their concern about animal well being very seriously. U.S. farmers have used the FDA approved growth enhancer since 2007, but it has been used around the world for almost twenty years. Big question now, what other companies will follow suit in boycotting a supplement used in almost half of U.S. beef?