December 31, 2003
US Feed May Be Source of Mad Cow Disease
Cattle feed produced in the United States could be the source of mad cow disease, officials on both sides of the border say.
The U.S. recently faced numerous problems ensuring that its feed mills did not mix cattle parts with cattle feed, a practice banned in North America in August 1997.
Dr. Francine Lord, manager of import-export for the Canadian Food Inspection Agency, said Monday from Ottawa that half the processed feed eaten by Canadian cattle comes from the U.S., and U.S. cattle consume half of the feed produced here.
U.S. feed could have infected "either one of them and that's why we always talk about, anyway on this side of the border, about a North American system for feeding cattle," Lord said.
Alberta Agriculture Minister Shirley McClellan suggested the two cases -- one found in May and one this month -- might be linked.
"Where the linkage might be is in the feed supply."
Feed records do not indicate a common source of contamination, Brian Evans, Canada's chief veterinarian, said Monday. He said that complicates the search: "We are going to go back another step in the chain to the feed mills to find out where they purchased the raw materials -- are they from a common source?"
New rules for feed were based on the finding that an infected cow could spread the disease if its brain and spine ended up in cattle feed.
Both animals diagnosed with mad cow disease were apparently born in Canada early in 1997, before the ban on cattle parts in feed took effect.
Pending results of a DNA test, available information suggests the diseased Holstein found in Washington state came from a farm north of Edmonton.
Scientists believe it takes three years for an infected animal to develop symptoms, which can include erratic behaviour and inability to stand.
A three-year gestation would indicate the Holstein contracted the disease in Alberta, where it lived until August 2001.
But Vikram Misra, a professor of veterinary medicine at the University of Saskatchewan specializing in infectious disease, said the mad cow outbreak in Japan provided evidence that cattle can show symptoms in only one year.
The Alberta case was a black Angus cow born in the spring of 1997 on a farm belonging to Mel McCrea of Baldwinton, Sask. McCrea said 95% of the feed he gave his cattle consisted of homegrown field crops. He also fed a protein supplement; McCrea believed it was free of cattle parts but said he can't be certain.
He said he did not know whether the supplement was made in Canada or the United States.
Bryan Babey, who owned the cow after McCrae, said he fed his cows barley and oats grown on his farm in Sandy Beach, Sask. He also gave them a protein supplement purchased from an Alberta mill but said it did not contain cattle parts.
In the U.S. on Monday, Dr. Ron DeHaven, chief veterinarian with the Agriculture Department, did not rule out that the cow in Washington state could have eaten contaminated U.S. feed.
The General Accounting Office, the investigative arm of the U.S. Congress, found in a 2002 report that hundreds of American feed mills were violating the ban on cattle parts. But the most recent inspection of these feed mills found that all but two of 1,664 were complying with the ban.
It is legal in the U.S. and Canada to feed rendered protein from cattle to pigs, chickens and other animals. And in the U.S., debris swept from poultry farms, consisting largely of food the birds have not eaten, can be fed to cows.
Cross-contamination in feed mills producing both cattle and chicken/pig feed is a possibility.
A mistake on a farm is also possible.
"On the bag, there's just a small printed phrase 'Do not feed to ruminants' " such as cattle, said Mark Ritchie of the Institute for Agriculture and Trade Policy in Minneapolis.
On the Canadian side, there are at least 600 mills providing feed to farmers. Some import protein supplements from the U.S.
Lord said her agency does not believe there were compliance problems in Canada after the 1997 ban. However, she acknowledged it has enough staff only to inspect feed mills an average of once every three years. Inspectors check the source of ingredients and the labelling.
Vernon Racz, director of the Prairie Feed Resource Centre at the University of Saskatchewan in Saskatoon, said most of the mills were removing cattle protein from feed before the 1997 ban because they knew about the problem.