The U.S. Department of Agriculture also said Thursday that the animal was 10 years and seven months old.
A spokesman for U.S. Rep. Devin Nunes of California had said Wednesday that the sick cow was 5 years old. It came from a dairy farm in Tulare County, the nation's No. 1 dairy-producing county.
The USDA didn't elaborate on the cow's symptoms other than to say it was 'humanely euthanized after it developed lameness and became recumbent'. Outward signs of the disease can include unsteadiness and incoordination.
Routine testing at a transfer facility showed the dead Holstein, which was destined for a rendering plant, had mad cow disease, or bovine spongiform encephalopathy.
Rendering plants deal with 'leftover' parts of cows that aren't suitable for human consumption - such as the hair and hooves. In the recent 'pink slime' scandal a small amount of rendered meat was found to have been used in some foods.
The results were announced Tuesday. It was the fourth case of mad cow disease ever discovered in the U.S.
Animals at greater risk for the disease include those with symptoms of neurological disease, 'downer' animals at slaughterhouses, animals that die at dairies or cattle ranches for unknown reasons, and cows more than 2 1/2 years old, because BSE occurs in older cows.
U.S. health officials say there is no risk to the food supply, as the California cow was never destined for the meat market but on Thursday Indonesia became the first country to suspend imports of U.S. beef following the discovery of the infected cow.
On Friday government officials in South Korea were carrying out checks on all U.S. imports.
The infected cow is believed to have developed 'atypical' BSE from a random mutation, something that scientists know happens occasionally.
Read more: http://www.dailymail.co.uk/news/article-2136114/Sick-cow-killed-random-mutation-warps-brain-cells-makes-lame-fourth-case-mad-cow-disease-U-S.html#ixzz1tHF1mCsZ
