Dec 29, 2003 (CIDRAP News) The Washington state cow announced by the US Department of Agriculture (USDA) on Dec 23 to be a "presumptive positive" bovine spongiform encephalopathy (BSE) case, was born in April 1997, before the August 1997 Food and Drug Administration ban on feeding ruminant-derived meat and bone meal supplements to cattle went into effect. The cow was originally thought be about 4-1/2 years old, but its owner rechecked records over the weekend and found the earlier birthdate, Dr. Ron DeHaven, USDA chief veterinarian, told reporters at a press briefing today. Also announced in the briefing was the fact that eight more cows from the infected animal's birth herd are being traced, bringing that total to 81 rather than the original 73.
On Dec 25, a world reference veterinary laboratory in Weybridge, United Kingdom, confirmed that the cow had BSE after receiving a hand-carried sample from the USDA, and on Dec 27, the USDA's traceback investigation indicated that the cow was likely imported from Canada in 2001.
Over 10,000 pounds of meat, comprising that from all 20 cows slaughtered at Vern's Moses Lake Meats in Moses Lake, Wash., on Dec 9, when the index cow was slaughtered, were recalled on the 23rd. States affected by the recall as of yesterday include Washington, Oregon, California, Nevada, Alaska, Montana, Hawaii, and Idaho, as well as Guam. This beef has an "essentially zero risk" of being infected with BSE, Dr. Ken Peterson of the Food Safety and Inspection Service, said at the briefing, but the recall was undertaken as a further precautionary measure. The infected cow's nervous system tissue, including the spinal cord and brain, did not enter the food system but was instead sent to rendering.
The experts at the briefing stressed the point that so-called downer cattle, meaning those that cannot stand, are not necessarily diseased. Injuries, sometimes even incurred during transport to a slaughterhouse, can cause an animal to be nonambulatory. A surveillance program was adopted in the United States in 1990 to test all downer cattle as well as cattle with any neurological signs and cattle over the age of 30 months for BSE. The Washington cow was nonambulatory, supposedly because of injuries from a recent birthing.