UNABLE to determine which calf was born to the nation’s first cow diagnosed with mad cow disease, US federal officials plan to kill a herd of 450 calves out of “an abundance of caution.”

INVESTIGATORS and retailers in eight states and a territory are scrambling to recover meat that may have come from a Holstein stricken with deadly mad cow disease.

Investigators tentatively traced the first US case of “mad cow disease” to Canada, which could help determine the scope of the outbreak and might even limit the economic damage to the country’s beef industry.