Reuters: Lost Hooves Prompted Tyson Foods to End Use of Zilmax

Reuters has a lengthy report today on the incidents that led Tyson Foods Inc. and other meatpackers to stop buying cattle that had been fed Zilmax, an animal feed additive produced by Merck & Co. Inc.

We noted Tyson's action this summer to stop buying Zilmax-fed cattle, as well as Merck's plan to study the drug's effects on animals.

Reuters' report sheds a little more light on the matter, including details of what led to Tyson's decision. For the Springdale company, the first signs of trouble surfaced at a slaughterhouse in Washington state, the report says:

As cattle trailers that had traveled up to four hours in 95-degree heat began to unload, 15 heifers and steers hobbled down the ramps on Aug. 5, barely able to walk. The reason: The animals had lost their hooves, according to U.S. Department of Agriculture documents reviewed by Reuters. The documents show the 15 animals were destroyed.

The next day, the hottest day of the month, two more animals with missing hooves arrived by truck. Again, the animals were destroyed, the documents show.

The animals’ feet were "basically coming apart," says Keith Belk, a professor of animal science at Colorado State University.

Tyson stopped accepting Zilmax-fed cattle the next day. Meanwhile Merck, in a statement to Reuters, stressed the safety of its product. It said a review of Zilmax, handled by third-party researchers it did not identify, "showed that the hoof loss was not due to the fact these animals had received Zilmax."