Update on BSE (Mad Cow Disease)

Dr. Jeffrey Walters
Dairy Newsletter Editor

US Secretary of Agriculture Mike Johanns announced on June 24 that positive identification of the first case of BSE occurring in a cow born in the US had been confirmed by tests at the Veterinary Laboratories Agency in Weybridge, England, which is the worldwide reference laboratory for BSE. This confirmation of the positive diagnosis came after the USDA submitted a sample from the suspect cow to the English lab after earlier tests in this country had given inconclusive results. The Secretary has also directed USDA scientists to work with international experts to develop a new protocol that includes dual confirmatory tests to strengthen US capabilities of detecting cases of this serious disease.

The affected animal was a twelve-year-old beef cow from a herd in south Texas. As a �downer� cow, the affected animal was not permitted to enter the human food supply. She was slaughtered at a pet food plant in November, 2004. As an older animal, this cow was born before the USDA instituted a ban on the use of most protein of mammalian origin in cattle feed in August, 1997. It is suspected that she probably contracted the disease through being exposed to contaminated feed before this date. Further testing for signs of BSE is being conducted in the cow�s living offspring and other older animals in the same herd. The BSE strain with which the cow was infected was different from that found in the first US case of BSE (a cow imported from Canada) and the one involved in the BSE outbreak in Britain in the 1980's, which may have complicated the diagnostic process. ©