Capital Press

POCATELLO, Idaho — The maker of the cattle feed additive Zilmax plans to start re-certifying feedlots to use the product, which it voluntarily pulled from the market last summer due to industry concerns about possible health effects on livestock.

Kevin Hill, technical services veterinarian with Merck Animal Health, said his company has begun “ramping up” re-certification efforts because feedlots want access as soon as Zilmax is available. No timeline has yet been set for its return, but Merck is planning additional Zilmax tests to evaluate how summer heat affects cattle.

Zilmax, a beta-agonist, is added to finishing rations to stimulate weight gain in the final 20 days before slaughter, causing cows to continue accumulating lean muscle rather than fat. It’s known to increase carcass weight by an average of 30 pounds, adding $24-$40 per animal in net profits. Sales of Zilmax, which had been the most widely used product for adding bulk before slaughter, totaled $159 million in 2012, Hill said.

Hill said re-certification training should refresh feedlot staff on proper procedures so “misuse is not part of that issue.” Merck has formed an advisory board of industry leaders to review data and set new protocols. Merck is also working to identify best management practices to minimize animal stress throughout the supply chain, which it views as another explanation for diminished animal health.

The product was removed in response to an August announcement that Tyson Foods would no longer buy cattle on Zilmax, which it linked to decreasing animal mobility at packing plants.

“They were careful to say they didn’t have any hard evidence that Zilmax was the issue, but they said, ‘We’re taking more Zilmax-fed cattle all the time, and there’s more lameness,’” Hill said.

Tyson Foods spokesman Gary Mickelson said his company’s position hasn’t changed.

“We’ll continue to evaluate this matter but don’t plan to resume buying Zilmax-fed cattle unless we are completely convinced our concerns have been properly addressed,” Mickelson said, adding foreign trade partners also have reservations about Zilmax.

Hill emphasized that the complaints don’t involve any threat to human health. Furthermore, the FDA and other worldwide regulatory agencies have not uncovered problems with Zilmax, despite rigorous testing.

Last August, Hill said Merck followed 65,000 of the final cattle fed Zilmax through the supply chain. Preliminary results of that audit show no evidence of health differences between Zilmax-fed cattle and other cattle, he said.

Idaho Cattle Association Executive Vice President Wyatt Prescott said he sees great importance in any product that “produces more pounds of beef by using less resources.”

Idaho Falls rancher Robert Johnson started a Zilmax trial shortly before the product was removed and would like to resume his evaluation as soon as possible. For now, he’s using the top competing product, Elanco’s Optaflexx, which he said adds about $15 in value per head but generally doesn’t get the same results as Zilmax.

University of Idaho Extension livestock specialist Wilson Gray emphasized 66 percent of cattle are now grading choice, an increase of 4 percent since the removal of Zilmax, which tends to reduce marbling in meat. Gray believes the industry has to consider if the extra beef is worth the lost quality.

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