The Holstein infected with mad cow disease in

Washington state was imported into the United States from Canada

about two years ago, federal investigators tentatively concluded

Saturday.

Dr. Ron DeHaven, chief veterinarian for the Agriculture

Department, said Canadian officials have provided records that

indicate the animal was one of a herd of 74 cattle shipped from

Alberta, Canada, into this country in August 2001 at Eastport,

Idaho.

"These animals were all dairy cattle and entered the U.S. only

about two or two-and-a-half years ago, so most of them are still

likely alive," DeHaven said.

DeHaven emphasized that the sick cow's presence in that herd

does not mean all 74 animals are infected. Investigators are

tracking down where the other 73 animals are.

"We feel confident that we are going to be able to determine

the whereabouts of most, if not all, of these animals within

several days," DeHaven said.

Confirming that the sick cow came from Canada will be crucial

for the United States to continue exporting beef because it could

retain its disease-free status. The country has lost 90 percent of

its exports because of the case, the National Cattlemen's Beef

Association estimates, because more than two dozen foreign nations

have banned the import of U.S. beef despite claims by U.S.

officials that the meat is safe.

Canada found a case of mad cow disease in Alberta in May. The

discovery decimated the country's beef industry as its importers

cut off trade.