Feds End Search for More Mad Cow Cases

The Agriculture Department is ending its search for additional cases of mad cow disease, even though officials have not found several animals suspected of having eaten the potentially infectious feed believed to have caused the lone known case in the United States.

The end of the search does not close the books on the mad cow case. Officials do not know the source of the feed thought to have sickened the Holstein, and they cannot be certain that all 95 million head of cattle in the United States are free of mad cow disease. The international review panel warned of the probability of other cases.

Also unknown is what happened to all 10,410 pounds of meat that was recalled from the slaughterhouse that processed the Holstein and mixed its meat with that of 19 other animals. Officials theorize people may have eaten some of that meat.

About 50 countries have banned American beef, its byproducts or live cattle; among them are Japan and Mexico, the United States' best customers.