Pinpointing the exact cause of lameness in feedlot cattle could be a challenge, says beef science expert

Losing the feed additive Zilmax isn’t a big deal in the short term, but losing a product known as “Vitamin Z” would have a huge impact, and reach far beyond the feedlot sector, says the science director for the Canadian Cattlemen’s Association’s Beef Cattle Research Council.

“Not having access to these tools doesn’t just impact the cattle feeders, it impacts society,” said Reynold Bergen.

Drug maker Merck has temporarily taken Zilmax, a type of compound called beta-agonist, off the market after Tyson Foods said it would no longer buy cattle given the growth promoter. Tyson said it was concerned it was the cause of mobility issues seen in cattle arriving at its plants.

Merck is suspending Zilmax sales until it investigates the situation, but Bergen said that lameness in finished cattle could have a host of causes — such as laminitis, foot rot, or transport injuries.

“It could be related to a lot of other things besides Zilmax,” said Bergen, adding that it will be “a challenge” for Merck’s investigators to pinpoint the cause.

The larger question, he said, is whether society wants the cattle industry to give up the hormones, implants, and feed additives such as beta-agonists that — along with improved genetics — have greatly improved productivity. Without them, it’s estimated the Canadian herd would have to grow by 10 per cent to produce the same amount of beef. That would mean using 10 per cent more land and feed, plus other inputs, said Bergen.

“We’d also need seven per cent more fuel, seven per cent more fertilizer, and the cattle would produce 10 per cent more manure and greenhouse gas emissions,” he said.

But the general manager of the Manitoba Beef Producers said he’s not expecting a consumer backlash against beta-agonists.

“They are safe to use. I have confidence in our regulatory approval process,” said Cam Dahl.

The Tyson ban, which he described as a marketing decision, is unlikely to depress prices, he said.

“With the lowest cow herd in North America since the 1950s, there’s no threat of excessive supply at the moment,” said Dahl.

Bergen added the average consumer tends to focus on price — not production protocols — when purchasing beef.

“If we went backwards because people didn’t trust the registration, surveillance and food safety process and raised beef the way our grandfathers used to do it, we’d need to make a choice,” said Bergen.

“We have more people, but not more resources. That’s where feed efficiencies come in.”

While a drop in beef productivity would limit supplies, it wouldn’t necessarily mean higher prices for cow-calf producers because it would also hurt the profitability of feedlots and their ability to buy cattle, both men said.

“If feedlots are operating on an economically sound footing, they tend to spend their money on calves,” said Bergen.

Canada’s top two packing companies, Cargill and JBS plan to continue buying Zilmax-fed beef.

Industry sources have said that many feedlots will likely switch over to Optaflexx, a ractopamine-based alternative to Zilmax’s zilpaterol, that is considered to be a milder beta-agonist with a lower impact on weight gain.

— Daniel Winters is a reporter with the Manitoba Co-operator at Oak Lake, Man. This article first appeared in the Aug. 29, 2013 issue.

Temple Grandin on beta-agonists: A Reuters Q+A

Merck and Co. recruited Temple Grandin, an advocate for the humane treatment of livestock, to be on a board that will consult on the company’s Zilmax feed additive, which has been temporarily taken off the U.S. and Canadian markets following animal welfare concerns.

Grandin, who frequently works for the meat industry, said she agreed to serve on the panel. Merck declined to divulge the identities of group invitees before board membership was set.

Reuters has spoken to Grandin several times since Tyson Foods on Aug. 7 said it would stop accepting beef fed Zilmax beginning next month. Below is an edited transcript of Grandin’s answers to Reuters’ questions.

Zilmax and other beta-agonists, a class of non-hormone growth promotants, are fed to cattle to add weight and reduce fat content in the meat prior to slaughter.

Grandin has designed equipment widely used in slaughterhouses. McDonald’s, Cargill and Whole Foods are among her clients. She told Reuters she has observed a succession of behavioral problems with cattle fed beta-agonists such as Zilmax , sold in Canada by Intervet, and Optaflexx, marketed by Eli Lilly’s Elanco unit.

Merck told Reuters it believes Zilmax is safe and the company is not aware of problems beyond those observed during the U.S. Food and Drug Administration approval process. It has said it needs time to “audit” how Zilmax was being used.

Elanco said in a statement that its agricultural feed supplement has been safely given to tens of millions of cattle, and reports of animals displaying problems “related to Optaflexx are very rare, and have decreased over time.”

Q: Tyson said its decision to stop buying Zilmax-fed cattle was based on animal welfare concerns. Have you noticed any issues at the slaughterhouses where you have worked?

A: When beta-agonists first came on the market in the early 2000s I worked at packing plants all the time. I started seeing problems showing up at packing plants that I’ve never seen before: stiff, sore-footed lameness and a lot of heat stress symptoms, including in Brahman cattle who are usually heat resistant. I want to emphasize not every group of cattle fed beta-agonists have this problem. Some groups of cattle have the problem and some don’t. I call it the “odd unevenness.”

Q: Have these issues been constant across the years?

A: I have seen it at five different plants with six different groups of cattle around the country. I saw it when ractopamine (Optaflexx) came out, then again when Zilmax came on the market. This summer, in particular, we’ve seen lots of these troubles. The hot weather really makes this worse. (Grandin said she did not know what additives had been given to the distressed cows she saw this summer.)

Q: Are these animals showing similar distress in the feedlots?

A: The cattle can look fine at the feedlot. Then you put them on a truck, take them to the plant, then put them in a pen for two hours, and then they don’t want to leave the pen. This is a problem that tends to show up more at the plant after you’ve stressed the cattle a bit.

Q: How common are these issues?

A: When there is a problem, half the cattle are perfectly OK. Then you have five to 10 per cent that are severely affected, reluctant to move, with sore feet and stiffness. Then you’ll have another 30 to 40 percent that are sore-footed and stiff, but it’s milder. I call it walking on hot metal. They act like the floor is hot.

Q: What are the signs of heat stress that you have encountered?

A: Open-mouth breathing, tongues out. These cattle are suffering. It’s cruel to have animals that are stiff and sore and hot and panting with their mouths open. Cattle don’t normally do that. Beef cattle do not need to be pushed to move. Cattle should run off the trucks.

Q: Are these problems caused by the animals being too heavy?

A: It’s not that the animals are too big for their legs. I’ve handled plenty of big cattle — this is not the cause of this type of lameness. It’s not the weight. It’s a different type of lameness that I have not seen before the introduction of these products.

Q: Would you like beta-agonist use to stop?

A: I’m not going to go so far as to say that. If I’m at a plant, I do not want to see this sore-footed lameness. I have worked 40 years improving how animals are handled at slaughter plants and now the cattle are hard to handle. You’ve got to get me cattle I can handle. — Reuters