For more than a year, a once-popular drug that makes cattle put on weight faster has been stuck in a kind of veterinary purgatory.
As far as the Food and Drug Administration is concerned, the drug, Zilmax, is legal to use. But large meat packers, which dominate the industry, have ostracized it after the drug was accused of making animals suffer. The drug's manufacturer, Merck, has been working on a plan to rehabilitate it. But that effort has stalled.