Calf herd killed after US mad cow outbreak

Federal workers using a vacant slaughterhouse in Washington state have killed a herd of calves that included the offspring of a holstein cow infected with mad cow disease whose bloodlines were traced to Canada.

The entire herd of 449 bull calves, ranging in age from 1 month to several months, was sedated and given lethal injections.

Agriculture officials had said the herd would have to be killed because the calf born to the sick cow was not tagged and could not be identified.

Officials have been unable to rule out the possibility that mad cow disease can be transmitted from mother to calf.