WASHINGTON – Two California dairy farms are under quarantine and a calf ranch is under investigation following discovery of the latest U.S. case of mad cow disease, but the government on Wednesday said the actions were standard procedure and there was no threat to the food supply.
Also, a calf born to the infected cow was found and tested negative for the disease.
Cattle records at the two dairies are being matched to determine if any at-risk cattle are on the farms, said the Agriculture Department.
USDA said the infected cow was a rare “atypical” case of the disease, meaning it arose spontaneously rather than through the feed supply. However, it is USDA’s standard procedure to search for other cattle, offspring or herd mates, that might be exposed to the fatal disease, even though mad cow disease is not contagious.