Canada Rejects Hormone That Boosts Cows’ Milk Output

Canada on Thursday rejected the use of a controversial hormone that boosts milk production in cows, giving U.S. consumer groups a weapon to attempt to overturn the Food and Drug Administration’s 1993 approval of the substance.

Canada’s rejection came after a report found that the substance might harm animals.

A review of existing data by Canadian scientists found no significant risk to human beings who ingest products from animals treated with the hormone but indicated that results of short-term tests on lab rats suggest that further study is needed.

The genetically engineered hormone--known as bovine growth hormone (BGH) or bovine somatotropin (BST)--has been widely used in the United States for nearly five years and in Brazil and Mexico for a decade. About 13,000 U.S. dairy producers use it, according to Gary F. Barton, a spokesman for Monsanto Co., the St. Louis-based manufacturer.

Monsanto, Barton said, will continue to pursue acceptance of BST in Canada and “will work with the health panel to resolve its concerns.” However, he added that the company was uncertain what its next step might be.

In the United States and Canada, longtime opponents of BST reveled in the action by Health Canada, the equivalent of the Food and Drug Administration in the U.S.

“This is quite a moment,” said Andrew Kimbrell, director of the Center for Food Safety, a nonprofit, public interest group in Washington. “This gives us just the scientific ammunition we need.”

Kimbrell said his group intends to file a legal petition today with the FDA requesting that the agency immediately rescind its approval of the hormone until concerns about animal health can be fully assessed.

Larry Bachorik, a spokesman for the FDA, said the agency “believes this product is safe and effective when used as labeled.”

The FDA approved Monsanto’s product, sold as Posilac, in 1993 over the objections of a wide array of farmers, consumers, conservationists and animal welfare activists. In addition to fears about the fledgling science of biotechnology, opponents expressed concerns about possible economic consequences for small dairy producers.

They noted at the time that, even without a growth hormone, America’s dairies had for decades been producing more milk than the nation could consume, forcing the federal government to buy up surpluses to prevent prices from plummeting.

Still, since going on the market in February 1994, the hormone has enjoyed robust sales gains, according to Barton. In 1998, he said, “we passed 100 million doses”--at $5.80 per dose.

Monsanto estimates that, of the nation’s 9 million or so dairy cows, 30% are in herds supplemented with the hormone. Fifty-five percent of customers have herds of 100 cows or fewer. (According to the U.S. Department of Agriculture, the nation has more than 116,000 producers, but many of those are quite small operations.)

Recombinant bovine growth hormone is a genetically engineered copy of a naturally occurring hormone produced by cows. The purpose of the hormone is to enable cows to produce 10% to 15% more milk than they normally would.

BST is also used in Brazil, Mexico and a dozen other nations.

Health Canada’s decision “is very bad news for Monsanto and for its plans for a world market,” said Jo Dufay, national campaigns coordinator for the Council of Canadians, a public interest group in Ottawa.

Monsanto, she said, had hoped that support by a North American bloc could help win acceptance of the product in Europe. The European Union, which in 1990 declared BST safe, three years later imposed a moratorium on its use until the end of the decade.

Health Canada noted that the decision was based on more than nine years of review and consideration of the recent findings of two independent advisory panels, including six prominent animal health authorities.

Veterinary experts cited a 25% higher risk of mastitis (udder infection), an 18% boost in the risk of infertility and a 50% rise in risk of lameness in animals injected with the hormone (particularly serious for dairy producers). These increased risks along with a generally weakened condition led to a 20% to 25% greater risk that a dairy cow using BST would be culled prematurely from the herd.

The increased risk of udder infections worried Canadian veterinarians, who said that could result in increased use of antibiotics, which could end up in milk. Scientists fear that over time human beings would build up tolerance to even the strongest antibiotics, making them useless against infection.

As for human beings, medical experts said a 90-day study of lab rats showed possible invasion of the hormone into the prostate. They also urged further study to learn exactly what happens in digestion and whether allergic reactions are possible.

Bovine growth hormone has created quite a controversy in Canada. Six scientists alleged that they were pressured to approve the drug despite their fears that it was unsafe. According to the Toronto Globe & Mail, one scientist told a Senate committee that Monsanto had offered government scientists a bribe of research money if they approved the drug. The company has denied that allegation.

Animal scientists in California said they had not seen any data that point to harmful effects in human beings resulting from drinking milk from cows treated with the hormone.

Times staff writer Eleanor Yang contributed to this report.