21st Apr, 2006: Vancouver, Candada - Veterinarians in Canada cut to the chase this week, checking feed sources for a Holstein cow confirmed to have bovine spongiform encephalopathy. The animal, euthanized last week after showing signs of BSE, was quickly traced to her birth farm.
“The producer has just excellent records,” said George Leuterbach, a Canadian Food Inspection Agency veterinarian.
Speaking by phone from a field office in British Columbia, Leuterbach said investigators moved to feed mills April 18 after getting detailed information from the birth farm. Another team sought disposition of two older offspring of the BSE cow, and identified all cattle born within one year of the BSE cow.
BSE is a rare and fatal cattle disease first scientifically described Britain in 1986. It is popularly called mad cow disease because of erratic gait and behavior of cattle as their brain tissue deteriorates.
The 6-year-old animal was part of a dairy near Chilliwack, B.C., a Fraser Valley town east of Vancouver.
She was a purebred, owned by the dairy for the past year. Leuterbach said she was born and spent the first five years of her life at a nearby dairy farm.
He did not identify either farm, but said they are both “well-known” in the Fraser Valley.
For the CFIA, that quick trace is prelude to a mystery yet to be solved: Where is Canada’s BSE coming from? The theory in previous cases, with the exception of a British-born animal diagnosed in 1993, is that contaminated feed – contaminated with protein from central nervous system tissue or organs known to concentrate the BSE-causing agent – is given to a calf.
That’s the basis for bans on feeding protein derived from ruminant animals to other ruminant animals. Both Canada and the United States began bans in 1997.
This marks the first native-born Canadian BSE case not linked with a cluster of BSE confirmations centered on Alberta, the Canadian province with the largest cattle population.
Hugh Lynch-Staunton, president of the Canadian Cattlemen’s Association, told Reuters he suspected some of the B.C. feed will turn out to be from Alberta. He also said finding another BSE case shouldn’t be a surprise.
Canada’s first case in 2003 had an after-the-fact British Columbia connection that Leuterbach said isn’t relevant to this investigation.
In that first case, the carcass was rendered into poultry feed before the routine BSE test was made. In tracing out where the feed went, the CFIA found a B.C. poultry farm where cattle grazing next to the hen house could possibly have eaten spilled chicken feed. Leuterbach said in this case, the B.C. BSE cow was born in April 2000.
What interests feed investigators, he said, is content of rations in the first year of a calf’s life. That includes how mills mixed formulations and were cleaned between running specific formulations.
Leuterbach told the Globe and Mail he suspects “a small amount or residual contamination” existed after the feed ban.
Chuck Strahl, Canada’s minister of agriculture, said late last week that more cases of the rare disease can be expected.
“We are likely going to have the odd recurring case for some time,” Strahl said.
The CFIA recently published preliminary rules tightening its ruminant feed ban. They’ve yet to take effect. A CFIA news release this week said the agency is “in the process of finalizing” details in the rule revision.
The U.S. government sent an investigation team to British Columbia early this week. They are under orders from Agriculture Secretary Mike Johanns “to determine what, if any, impact this should have on our beef and live cattle trade with Canada.”
Imports of selected steers and heifers, including feeder cattle, resumed in July 2005 after being suspended since May 2003. The USDA limited those imports to animals under 30 months old, on the theory that the average BSE case expresses itself at 60 months age and becomes detectable about one year before. A rule that would allow resumption of over-30-month-old cattle is under consideration by USDA officials.
by Tam Moore