The plan was created as a response to last week’s announcement from Tyson Foods that it would suspend purchases of cattle finished on Zilmax, starting Sept. 6.

Tyson Foods said it was concerned that the use of Zilmax may be a contributing factor to non-ambulatory cattle at its processing facilities.

Zilmax, known as the clinical name zilpaterol, is one of two beta agonist feeding supplements on the market. It is fed to cattle in mixed rations and builds muscle mass in the finishing stages for fed cattle. It has been attributed as a key factor in helping the cattle industry increase pounds of beef produced in spite of fewer cattle slaughtered.

Merck, the makers of Zilmax, has defended the product by citing its 30 years of research and testing. To back up that testing, Merck announced a “Five-Step Approach to Ensuring Responsible Beef” program.

The company said it will immediately start a certification program for every feeder, nutritionist and vet that feeds Zilmax to cattle. “Special attention will be given to feed mixing and determining which cattle are good candidates for the use of beta agonists,” the company said in a statement.


That certification will use third-party experts to provide the periodic review of certifications.

Merck also pledged to start an outreach program to packers and suppliers to begin a scientific audit program focused on Zilmax feeding, and try to determine “potential causes of lameness and other mobility issues during feeding, transportation, offloading and staging at the processing facility.” Those audits will also be done with third-party experts, the company said.

Rounding out its five-step plan, Merck also said it would have feeders uphold the appropriate management practices for nutrition and feeding objectives, animal handling, transportation and low-stress environments. It will also form an animal health advisory board with feeders, packers and cow-calf operators, and others, to review management practices. It also pledged to share findings in a transparent manner.

The National Cattlemen’s Beef Association on Tuesday made a statement commending Merck for its program to certify and train those using the product. The association said beta agonist restrictions should be based “on science, not speculation” and that there is no scientific basis for saying the supplements caused the animal welfare issues noted by Tyson.

NCBA also said it has gathered top animal welfare expertise on the product in recent months, to understand any relation to animal well being.

“Our goal is to fully understand how the use of these products impacts animal welfare in real-life conditions. If this process determines the current use of beta-agonists is compromising animal welfare, we will take appropriate action to ensure that every animal raised for food receives the proper care it deserves.” end mark