As Beef Cattle Become Behemoths, Who Are Animal Scientists Serving? - The Chronicle Review - The Chronicle of Higher Education
The article focuses on how public university professors get money from drug companies for their research and do not disclose their conflict of interest. But it also says:
Dressed in a white lab coat, a hard hat on his head, Lawrence pointed to the carcass of a Holstein that had been fed a new drug called Zilmax. He noted its larger size compared with the nearby body of a steer never given the drug. "This is thicker, and it's plumper," said Lawrence, an associate professor of animal science, pointing at the beast's rib-eye. "This animal right here," he said, waving his hand at the pharmaceutically enhanced meat, "doesn't look like a Holstein anymore."
To gain government approval for Zilmax, Intervet provided data from studies testing the drug in rats, monkeys, mice, small pigs known as Yucatan microswine, and a few dozen humans. In the human volunteers, the drug increased heart rate and caused tremors. The FDA requires ranchers to stop feeding Zilmax to cattle at least three days before they are slaughtered, to ensure that any remaining traces of the drug are at a level safe for humans.