Mad cow case could have roots in imported American cattle, says report
at 13:48 on July 3, 2003, EST.
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Cattle graze at a feedlot near Picture Butte, Alta., approximately 25 kilometres north of Lethbridge, Tuesday. (CP PHOTO/Adrian Wyld)
EDMONTON (CP) - The single case of mad cow disease that has paralysed the Canadian beef industry may have originated in cattle imported from the United States five years ago, says the Canadian Food Inspection Agency.
In a final report on its investigation into the outbreak, the agency refers to an unusually large 1998 shipment of 25,000 pregnant U.S. cows who had been born before the ban was imposed on feeding animal protein back to cattle.
"Canada cannot, to date, exclude the possibility that the index case itself derived through this huge, unique importation," the report says.
Because the cows were brought in before the start of the Canadian Cattle Identification Program, those cattle lost their identification as American imports.
"There was one year where the regulation was interpreted as allowing animals to be brought directly into Canadian feedlots without testing for brucellosis and anaplasmosis," said Dr. Claude Lavigne of the food agency.
"It was interpreted as allowing sexually intact animals to come in and some of these animals did not remain in feedlots."
The report says 70 per cent to 80 per cent of those cattle were Black Angus, the same breed as the northern Alberta cow that later developed mad cow disease. The cows have long since integrated into the general Canadian population and entered the feed chain.
U.S. officials have known about the possible American connection since June 12, Lavigne said.
The report underlines the extent to which the Canadian and American cattle industries are integrated, he added.
"All of the risk elements are there and are common to both countries. If you combine that with the known fact that there has been a lot of movement across the border, you end up with very similar risk factors in both countries.
"It probably could have shown up in the U.S. and may still."
There's little chance the imported cattle could be tracked back to their American farms of origin, Lavigne said.
"The trail is cold. It would probably be close to impossible to find the exact origin of all these animals. They've lost identification on the way."
The agency is also revisiting the 1993 discovery of a mad cow infection in an Alberta bull that had recently been imported from England.
Scientists theorize that other infected cattle may have come over before the 1993 case was discovered and that low levels of bovine spongiform encephalopathy may have cycled between herds, rendering plants and feed mills until 1997 when the feed ban was enacted.
That ban does not allow feed derived from ruminants such as cows and sheep to be fed to other ruminants.
The brains from the British cows imported with the infected bull have been preserved.
"They are being reassessed to determine, with sensitive diagnostics unavailable at the time, the degree to which the BSE threat may have extended beyond the single clinical case," the report says.
Canada has also contacted British officials to see if any of the herds of origin of those imported animals have developed mad cow disease.
The federal agency all but ruled out the possibility of the mad cow infection arising from wild or domestic elk herds.
A similar ailment, called chronic wasting disease, has appeared in elk and deer in both Saskatchewan and Alberta, but no link with BSE was found.
"The possibility that they might transmit the disease directly to intensively commingling cattle has been explored, with negative results to date in protracted studies in the U.S."
The report also rules out the possibility the single Alberta case arose spontaneously.
Since the case of mad cow was discovered May 20, the borders of almost all Canada's major trading partners have been closed to Canadian beef.
Producers estimate the closures are costing them $11 million a day. The economic pain has spread to related industries and rural communities.
BOB WEBER