Merck: Too soon to tell when Zilmax will be back

Published on: Dec 13, 2013

MERCK Animal Health said there was no timeline yet for reintroducing its beta agonist product Zilmax in the North American market. The company suspended sales of the product in August after Tyson said it would stop purchasing cattle finished on the popular growth-promoting feed additive.

“During the last 90 days, Merck Animal Health, with the input and oversight of its Advisory Board, has worked to implement its Five-Step Plan to Ensuring Responsible Beef,” the company said in a statement Dec. 13. “While we have made considerable progress, it is too early to determine when Merck Animal Health will return Zilmax back to the market in the United States and Canada.”

As part of its plan, the company convened an Animal Health Advisory Board comprised of representatives from packers, large, medium and small cattle feeder operations, cow-calf producers, veterinarians, academia and industry consultants. Working since August, the Board was charged with reviewing all available animal safety and well-being research data on Zilmax; the company’s existing Zilmax Quality Assurance program (ZQA); the proposed certification and scientific audit processes; and best management practices for using Zilmax.

Merck said that when it resumes sales of the product, which topped $159 million in 2012, users will be required to obtain a formal certification that will ensure proper use of Zilmax. As part of that certification, every feedyard team member, nutritionist and veterinarian who uses Zilmax or provides consultative services on feeding the product to cattle must be trained annually on the proper use of the product.

The training will focus on safety practices, product handling, mixing protocols, cattle management, product inventory, record keeping and clean-out procedures. Every certified operation will also be required to pass an initial homogeneity test to ensure proper mixing practices, as well as four additional feed mix tests throughout the year. Before a feedyard can participate in the Zilmax Field Evaluations, the operation will need to be certified. 

Another key component of its “responsible beef” plan is a wide-ranging scientific audit of the product and its use in the field. Merck’s Advisory Board helped develop and finalize the protocol for the field evaluations for trials comparing Zilmax-fed and control cattle groups, with evaluations expected to begin during the first quarter of 2014.

The evaluation will include observing cattle throughout the system, both before and after receiving Zilmax, at the feedyard and at the packing plant. Third-party experts will evaluate the mobility of cattle utilizing an established mobility scoring system, and the analysis will review potential compounding factors, such as nutrition, transportation, receiving facilities, flooring surfaces, and cattle management and handling practices.

Merck said that its field evaluations will take place with the oversight of a well-known independent epidemiologist and veterinarian, who will serve as principal investigator and collect all data, analyze results and publicly communicate findings in support of the company's commitment to transparency and communication.

“We at Merck Animal Health remain highly confident in the safety of Zilmax, which is supported by the results of more than 30 studies, totaling 65,000 cattle that were conducted by well-respected universities and third-party experts,” said KJ Varma, Merck’s senior vice president of global R&D. “We believe the field evaluations we are conducting as part of the five-step plan will support the results of previous studies and the safety of the product, and we are confident that they will help create a greater understanding of the best management practices that are so vital to helping ensure the well-being of cattle.”

Controversy over the use of beta agonists, including Zilmax and Elanco’s competing product Optaflexx, have caused some issues with U.S. beef exports, as Russia suspended imports in January. Last month the U.S. Department of Agriculture announced the approval of a “never fed beta agonist” marketing claim that might help packers reenter the formerly lucrative market.