After Cows' Feet Fall Apart, Feedlot Drug Is Questioned - Reuters' special report zeroes in on Merck's muscle-building Zilmax

"...Their feet were "basically coming apart," says an animal science professor who was provided with photos of the affected cattle by an unnamed person. Tyson reacted quickly to the August incident, immediately saying it would no longer receive cattle that had taken Zilmax; other meatpackers followed suit, and Merck temporarily put all Zilmax sales on ice..."

http://www.newser.com/story/179951/after-cows-feet-fall-apart-feedlot-drug-is-questioned.html