In December 23, a dairy cow at a Washington State slaughter facility tested positive for bovine spongiform encephalopathy, or mad cow disease, the first such occurrence in the United States. U.S. officials now say evidence suggests that the infected cow was born in Canada in 1997, before the enactment of bans that prohibited the use of cattle feed containing protein from cows, goats or sheep. "Even with the finding of this single cow, the U.S. remains at very low risk," USDA chief veterinary officer Ron DeHaven... More >>>