Investigators looking into California's first case of mad cow disease say they have tracked down at least one of her offspring in another state.
Since there is no live test for the disease also known as bovine spongiform encephalopathy, it was euthanized and brain samples were sent to the national laboratory. The test was negative, officials said Wednesday.
The USDA announced April 24 that the nation's fourth case of mad cow disease was discovered in the 10-year-old cow. It had been euthanized at a Tulare County dairy a week earlier and sent to the Baker Commodities rendering plant near the Central California town of Hanford, where random testing happened to be taking place that day.
That dairy and another associated with it are under quarantine, which is standard procedure. The USDA has declined to name the dairies or the state where the offspring was found.
USDA officials also said on Wednesday that within the last two years, the diseased cow gave birth to a stillborn calf. They did not say how that carcass was disposed.
Officials also are investigating the calf ranch where the diseased cow was raised before she was sold into dairy productions. Investigators said they have been unable to locate for testing the cattle that were raised with the one who developed mad cow disease.
Mad cow disease is a deadly affliction of the central nervous system that can be transmitted to humans who eat meat from infected cows. The incubation period is two to eight years.
Cows can contract the disease by eating rendered remains from other sick cattle, which are processed into protein supplements. It's no longer legal to feed cattle to cattle, but rendered cattle are fed to chickens, and chicken droppings and spilled feed are rendered back into cattle feed.
The FDA and the California Department of Food and Agriculture have been examining feed records at the affected dairy and have identified at least 10 suppliers.
The USDA tests 40,000 of the approximately 35 million cattle slaughtered annually for BSE. Baker Commodities is a voluntary participant in the testing program.