Birth cohort of Canadian mad cow exported to U.S.

WASHINGTON (Reuters) - A heifer born from an animal in the same herd as a Canadian bull diagnosed in February with mad cow disease was exported to the United States in 2002, but a U.S. official said on Tuesday there is no evidence the animal had the brain-wasting disease.

The heifer was sent to a feed lot in Nebraska and later slaughtered in the state at a facility overseen by a U.S. Agriculture Department inspector.

After discovering the infected bull, Canadian inspectors looked at other animals born in the same herd during the previous 12 months.

"It most likely" entered the food supply "given that it was slaughtered," said Karen Eggert, a spokeswoman with USDA's Animal and Plant Health Inspection Service.

"But it wouldn't have gone to slaughter if it was showing any clinical signs for BSE. We're not looking at this as a possibility that a BSE infected cow got into the United States," she said.

Tests released in early February confirmed mad cow disease in the mature bull in Alberta. Canada has reported nine cases of mad cow disease, or bovine spongiform encephalopathy (BSE), in its domestic herd since May 2003. All the animals are believed to have contracted the disease from contaminated feed, a primary way mad cow can spread.

Currently, Canadian ranchers can send cattle under 30 months of age to the United States for slaughter, and imports of beef from younger cattle are allowed.

The United States has proposed allowing imports of Canadian cattle born on or after March 1, 1999, and meat from older animals, now blocked out of concerns over mad cow disease.