Federal officials have so far found 29 of the 80 head of Canadian cattle that entered the United States in 2001 with a Holstein (search) infected with mad cow disease.

The latest animal, which was located Thursday, would be euthanized after being tested, the U.S. Agriculture Department said Friday.

Investigators have been working to locate the cattle since the announcement Dec. 23 that a cow at a Mabton (search) dairy farm had tested positive for mad cow disease. That cow was slaughtered Dec. 9.

The animal found Thursday also was found in Mabton, but at a different farm, authorites said.

Mad cow disease eats holes in the brains of cattle and is incurable. It is a public health concern because humans can develop a brain-wasting illness, variant Creutzfeldt-Jakob disease (search), by consuming contaminated beef products.

Contaminated feed is believed to be the source of the infection in animals. The Agriculture Department says it has identified 14 of the 25 cattle most likely to have eaten the same feed as the diseased cow. The animal located Thursday was not believed to be among them, officials said.

More than 700 cows have been slaughtered since December as part of the mad cow investigation.