Tyson to suspend purchase of Zilmax fed cattle

The company said that it made the decision after cattle delivered to some of its plants with difficulty walking or unable to move.

“We do not know the specific cause of these problems, but some animal health experts have suggested that the use of the feed supplement Zilmax, also known as zilpaterol, is one possible cause,” it said in a letter to US cattle feedlots.

“Our evaluation of these problems is ongoing but as an interim measure we plan to suspend our purchases of cattle that have been fed Zilmax,” the letter said.

Zilmax is beta-agonists, which boost animal weights and produce lean muscle in cattle and hogs, instead of fat. It is blended with other feed rations and vitamins and fed to cattle during the last few weeks they are in feedlots before being processed into beef. Some animal-welfare and consumer-safety groups have been critical of the additive’s use.

Merck & Co, whose animal health division manufactures the additive, said in a statement that tests have proven that Zilmax is safe and that it was working with Tyson.

The suspension will begin from the 6th of September.

The news of the suspension also prompted a surge of live-cattle futures in electronic trade – hitting a 3 month high.