"Our investigation is now complete," said Ron DeHaven, deputy administrator of USDA's Animal and Plant Health Inspection Service."We feel confident that the remaining animals, the ones we have not been able to positively identify, represent little risk."

The announcement came yesterday, and it means USDA will no longer look for additional cases of bovine spongiform encephalopathy in the U.S. cattle population, following the discovery in December of one infected cow.

There are 11 head of cattle that have not been located from the original 25 that USDA officials believe may have eaten the same feed as the BSE-positive cow in Washington state. The feed is expected to be the likely mode of infection.

The 25 dairy cattle were among 81 born that were born in Canada, and exported to the United States in 2001. USDA did locate 29 of the orginal 81, 14 of those were labeled "most at risk."

USDA investigated 189 farms and ranches, tested 255 animals in its pursuit of the imported cattle, none of the animals tested came up positive for BSE, said DeHaven.

Source: USDA