US officials are investigating another possible case of BSE.

USDA chief veterinarian John Clifford said testing indicates a cow that was at least 12 years old may have had the disease. He said the USDA received non-definitive test results on July 26 on the cow and is sending samples to a laboratory in Weybridge, England, for further testing. Test results are expected to be released next week.

Clifford did not say where the cow came from and said it died during calving. He said the cow does not pose a threat to the US food supply because it did not enter the human food or animal feed chains.

The United States has had two BSE cases - one confirmed last month in a 12-year-old Texan cow and one in a Canadian-born cow that was discovered in 2003 in Washington State. More than 419,000 animals have been tested for the disease, according to the USDA.