The Texas cow infected with mad cow disease was sold through a livestock market and taken to a slaughterhouse where it was dead on arrival, the Agriculture Department said Friday.
The cow wasn’t unloaded or presented to the slaughterhouse because it was dead, the department said. Instead, it was shipped to a pet food plant in Waco, Texas, that took brain samples for testing. The 12-year-old cow was a yellow or cream-colored Brahma cross, the department said.
Officials released the information about the cow’s last days as part of its ongoing investigation into the animal’s history.
The department is trying to find offspring born in the past two years and herd mates born within one year of the infected cow’s birth, but officials said they don’t expect to find another case.
“If world experience is any indication, it’s very rare that you get a second case out of the same herd,” Agriculture Secretary Mike Johanns told reporters Friday.
The cow was sold Nov. 11 through the market, where at one point there was a report that it was a “downer,” unable to walk. It was shipped with a load of other cows on Nov. 15 to the slaughterhouse, where it was dead on arrival, and then to the pet food plant later that day.
Initial screening indicated the presence of the disease, but results from more sophisticated tests were negative, and the department declared the animal to be free of mad cow disease.
The agency’s internal watchdog ordered another round of tests last month that came back positive, and a laboratory in England confirmed the results on June 24. It is the first native case of the brain-wasting disease. The only other case was confirmed in December 2003 in a Canadian-born dairy cow that had been shipped to Washington state.
The government is also tracing the herd’s feed history. The only known way for cows to get the disease is by eating brain and other nerve tissues of already-infected cows. Ground-up cattle remains from slaughtering operations were used as protein in cattle feed until the U.S. banned the practice in 1997.
The department said that given the Texas cow’s age, it probably was infected before the ban. Most of the nation’s cattle herd was born after the feed ban, according to estimates from the National Cattlemen’s Beef Association. However, the government does not maintain data on the 96 million U.S. cattle. Officials are planning to establish a nationwide livestock tracking program by 2009.
The cow was born and raised on a single Texas ranch; officials have not identified the ranch or the owner. State officials have confined the herd while the investigation is under way.
Mad cow disease is the common name for bovine spongiform encephalopathy, or BSE. Eating infected tissue from cows has been linked to a rare but fatal disease in humans called variant Creutzfeldt-Jakob disease, which is blamed for the deaths of 150 people in Britain, where there was an outbreak in the 1980s and 1990s.