WASHINGTON - A cow in Alabama has tested positive for mad cow disease, the Agriculture Department said Monday, confirming the third U.S. case of the brain-wasting ailment.
The cow did not enter the food supply for people or animals, officials said. The animal, unable to walk, was killed by a local veterinarian and buried on the farm.
"We remain very confident in the safety of U.S. beef," said the department's chief veterinarian, John Clifford.
The news came as the Bush administration worked to reassure Japan and other foreign customers of American beef. Japan halted U.S. beef shipments in January after finding veal cuts with backbone - cuts that are eaten in the U.S. but not in Asia.
Japan was the top customer of American beef until the first U.S. case of mad cow disease prompted a ban it had only recently lifted.
"We would not anticipate that this would impact our ongoing negotiations," Clifford said. "Our product is safe. We've got a number of interlocking safeguards. And Japan themselves have had 20-plus cases of BSE."
Mad cow disease is the common name for bovine spongiform encephalopathy, or BSE.
The first U.S. case of mad cow disease appeared in December 2003 and involved a Canadian-born cow in Washington state. The disease was found again last June in a cow that was born and raised in Texas.
The local vet examined the Alabama cow's teeth and said the animal was older, "quite possibly upwards of 10 years of age," Clifford said. Investigators are working to pinpoint the cow's age, he said.
The age of the cow is important because the U.S. put safeguards in place nine years ago to prevent the disease from spreading. The U.S. banned ground-up cattle remains from being added to cattle feed in 1997. Eating contaminated feed is the only way cattle are known to contract the disease.
Older animals are more likely to have been exposed to contaminated feed circulating before the 1997 feed ban.
In Canada, which enacted a similar feed ban in 1997, the most recent case of mad cow disease was in an animal born after the feed ban, raising questions about enforcement. That case was confirmed in January in Alberta.
The Alabama cow had spent less than a year at the farm where it died, Clifford said. Investigators are working to determine where the cow was born and raised and locate its herdmates and offspring, Clifford said.
The Agriculture Department has been considering when to scale back its higher level of testing for mad cow disease. After the first case of BSE, testing was increased from about 55 to 1,000 daily. As of Monday, 652,697 of the nation's estimated 95 million head of cattle had been tested.
The department hasn't decided how many animals to test once surveillance is scaled back but will follow international guidelines, Clifford said.
In humans, eating meat products contaminated with BSE has been linked to more than 150 deaths, mostly in Britain, from variant Creutzfeldt-Jakob Disease, a rare and fatal nerve disease.