The US Department of Agriculture says it has identified the source of the case of BSE confirmed recently.

"DNA test results have confirmed that we have identified the source herd of the animal determined last week to be positive for BSE," USDA chief veterinarian John Clifford said in a statement.

"Based on information we have received from the owner, the cow was born and raised in a herd in Texas and was approximately 12 years old," he said. "It was sent to a pet food plant in Texas and was selected for sampling on arrival."

"The source herd is now under a hold order as we identify animals of interest within the herd," he said. "Consistent with OIE guidelines, animals of interest would include any other animals that were born the same year as this animal, as well as any born the year before and the year after. If the age of the animal cannot be pinpointed, then we may expand our inquiry to include all animals in this herd before the feed ban went into place in 1997. We are also interested in any of this animal's offspring that were born within the last 2 years."

"Experience worldwide has shown us that it is highly unusual to find BSE in more than one animal in a herd or in an affected animal's offspring. Nevertheless, all animals of interest will be tested for BSE," he said. "We are also working with the Food and Drug Administration in an effort to determine the feed history in this herd. Given the animal's age, we believe it was most likely infected by consuming feed prior to the implementation of the ruminant-to-ruminant feed ban in 1997."

"I emphasize that this animal did not enter the human food chain," he said. "The plant at which this animal was sampled is a … pet food plant that does not handle animals for human consumption and, in this case, did not use the animal in the production of pet food. The animal remains were incinerated."

"The testing and traceback efforts may yield further information as to how this animal became infected," he said. "The safety of our food supply is not in question. I am very confident that our interlocking safeguards are effective, and this case is evidence of that. USDA bans nonambulatory cattle from the food supply. USDA bans animal parts that could carry BSE from the food supply. USDA bans slaughter techniques that could introduce BSE into the food supply. These safeguards ensure that American beef is among the safest in the world."