CHICAGO (Reuters) — Merck & Co Inc
wants to feed its controversial feed additive Zilmax to 240,000 U.S.
cattle to prove it is safe. But there is a problem: giant meat
processors like Cargill Inc don't want to touch animals fed with the
Merck plans to conduct the biggest ever test of its kind in an
effort to reintroduce the weight-adding drug into the United
States and Canada after suspending sales last August. A test
herd of this size is currently worth up to $500 million.
Feedlot owners, however, are reluctant to participate in the
study until they get a guarantee that slaughterhouses will be
willing to buy the Zilmax-fed animals.
Snags with the study, whose size was confirmed to Reuters by
Merck, have not been previously reported.
"I'd be happy to sign up, just as soon as Merck tells me who is
going to pay me after they're done," said a feedlot owner in
Texas. "It's been a horrible time, with the drought. I can't
afford to give away a steer, let alone hundreds."
Cargill Inc and Tyson Foods Inc, two of the world's largest beef
processors, told Reuters their stance on Zilmax had not changed
since last autumn, when they stopped accepting cattle fed the
drug following reports it may cause lameness. Together the two
companies control 37 percent of the daily U.S. beef processing
Reuters reported in December that Tyson stopped taking Zilmax-fed
livestock after more than two dozen animals that had been fed
the drug arrived at one of its slaughterhouses with missing
The beef processors said their ban would remain until Merck had
scientifically proven that Zilmax was safe for animals. They
also want certainty that key export markets in Asia and
elsewhere will accept such beef products.
Merck has said it is confident in the "safety and performance"
of Zilmax. The U.S. Food and Drug Administration has deemed the
drug safe for both animals and humans.
A source with National Beef Packing Company said the company was
not accepting Zilmax-fed cattle. JBS USA Holdings Inc, another
major beef processor, did not return calls and emails for
Merck in December said the evaluations would start in the first
quarter. But company spokeswoman Pamela Eisele declined to say
this week where the 240,000 cattle would come from in the United
States, whether the tests had started, or whether Merck had
signed up any packing plants, ranchers or feedlots — which house
and fatten up the cattle before they are slaughtered.
Eisele said the company's current plan was to sign up at least
50 U.S. feedlots, out of more than 73,000 nationwide, to
participate in field tests over several months. Merck hopes to
enroll five to 15 feedlots for each slaughterhouse that agrees
to process the cattle, she added.
Anne Burkholder, who runs a 3,000-head feed yard in Cozad,
Nebraska, is eager to hear results.
"We need to have a large study, where we can really look at
mobility and well-being issues we're seeing in the present,"
said Burkholder, who switched to another feed additive after
Merck suspended Zilmax sales.
The attempt to launch a large-scale study underscores Merck's
determination to put zilpaterol-based Zilmax, once the
largest-selling growth drug for cattle, back on the lucrative
agriculture drug market.
The scale is unprecedented for a randomized, controlled study of
cattle, and the logistics involved with tracking so many cattle
"boggle the mind," said Morgan Scott, an epidemiology professor
at Kansas State University.
Merck said it believed the field evaluations will "support the
results of previous studies and the safety of the product."
A principal investigator hired by Merck, who is an
epidemiologist and veterinarian, will oversee the study and
analyze data, Eisele said.
Merck has declined to name the investigator, or any of the
scientists or other academic experts involved in the study, but
said it would release the results once the study was completed.
Some livestock researchers have questioned why Merck has
declined to say who is leading the research effort. Others have
criticized the company for promoting the study's outcome before
data are collected or analyzed.
"It would suggest that they've already decided the results,"
Christopher Reinhardt, a feedlot extension specialist at Kansas
State University, said meat packers and feedlots will make
certain results are objectively reported. Merck has "a vested
interest in the outcome but their partners don't, so there is
sort of a check and balance in place," he said.
Animal science experts said large-scale field studies — if done
well — can offer valuable insight into drug interactions and
impacts in the real world after the initial laboratory vetting
required for federal regulatory approval.
With Zilmax off the market since last August, rival
pharmaceutical firms have grabbed market share. Many U.S.
feedlots have switched to ractopamine-based Optaflexx, made by
Merck rival Eli Lily & Co.'s Elanco Animal Health unit.
(Reporting by P.J. Huffstutter and Tom Polansek. editing by
David Greising and Ross Colvin)