Scientific review | Merck Animal Health to examine growth promotant banned at Tyson Fresh Meats plants
In a surprise move, Merck Animal Health has temporarily suspended sales of the beta agonist Zilmax in Canada and the United States.
When Tyson’s Fresh Meats said it would no longer accept cattle fed the product because it had seen problems with animal lameness, Merck defended Zilmax but promised a research project to determine if the concerns were valid.
“We remain confident in the safety of Zilmax and the well-being of the animals that receive it, as confirmed by independent university studies, official review by regulatory authorities and our own extensive research,” said company spokesperson Amy Firsching in an email on Aug. 19.
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“We will not accept new customers in the U.S. and Canada until the five-step plan has been completed and the results are documented,” she wrote.
The review has five steps:
- The company has promised more training for veterinarians, feeders and nutritionists.
- Merck will engage third party experts to review certifications.
- Working with a third party agency, Merck promised to initiate a scientific review to follow cattle fed Zilmax from feedlots to packing plants to determine potential causes of lameness and other mobility issues during feeding, transportation, offloading and staging at the processing facility.
- The company said it will also examine nutrition, transportation and receiving facilities to assess their impacts on mobility.
- A Merck Animal Health advisory board is planned to review data and will include feeders, packers, cow-calf operators, as well as animal health and nutrition experts.
The company has promised to share its findings.
Jeff Warrack, chair of the National Cattle Feeders Association and an owner of Bruce Farms east of Calgary, said his operation has seen no problems with Zilmax in the six months it was used.
“There must have been something else coming down the pike and this is just their way of nipping it in the bud,” he said.
“I guess if there is a problem with it, we’ve got to find out,” he said.
When first approved, Merck company representatives visited feedlots to train staff and provided operating procedure manuals.
“We started using it this spring and there is a pretty good response to it and we’re certainly not seeing any incidences of lame cattle,” Warrack said. He figures it netted his operation an extra $10 per head because of the added weight gain at the end of the feeding period.
“It is disappointing that they have come out in the media saying it is an animal welfare issue, but I doubt it is,” he said.
If he shipped lame cattle, the plant would be in touch to see what went wrong.
“You don’t load extremely lame cattle or cattle that have trouble keeping up with the group, that is what the code (of practice) says so you wonder if there is a breakdown in the system,” he said
Zilmax contains zilpaterol hydrochloride, while the Optaflexx growth promotant, an Elanco product, contains ractopamine hydrochloride. Optaflexx has not been affected.
These products are known as beta agonists, which increase muscle growth and decrease fat deposition to produce a larger, leaner carcass. Cattle are fed the product in small amounts for 20 days and can gain an extra 15-35 pounds before they are sent to slaughter. The withdrawal period in Canada is four days.
At this point no one is sure what was behind the decision.
“Our concern is that we have lots of products that are approved for use and they may be a little controversial. In the end, if the market and the consumer doesn’t want them, we are not going to use them but I’m not sure if this is really the case here,” Warrack said.
“We’re running businesses here. We are not cutting corners but if you can use the technology that is available to you, that’s going to keep you in the game,” he said.
The market analysis firm, the CME Group said weekly slaughter rates between 2007-2011 were consistent but a large jump was noted in early 2012 following widespread adoption of the product.
Carcass weights increased about 20 pounds per head from February onward. If feeders switch to Optoflexx the analysts calculate carcass weights would drop by six to eight pounds less than those fed Zilmax.
One agriculture economist said this decision could reduce the overall beef supply in the United States. It is not known if feedlots might switch to Optaflexx and what the full impact on total beef production might be, said Glynn Tonsor of Kansas State University.
“It will reduce beef production starting in the fourth quarter and moving into 2014,” he said.
There is no firm information on how widely beta agonists are used but Tonsor estimates 60-80 percent of U.S. feedlot cattle receive them.
High input costs have pushed profitability out of the feedlots so there were incentives to use the technology, especially when corn was as high as $8 per bushel.
