Mad Cow Disease

On December 23, 2003, the U.S. Department of Agriculture (USDA) discovered bovine spongiform encephalopathy (BSE), also known as mad cow disease, in a single “downer” (i.e., nonambulatory disabled) dairy cow in Washington state. The birth of the BSE-positive cow was traced back to a farm in Alberta, Canada.

The USDA collaborated with state and other federal animal and public health agencies, industry representatives, and the Canadian Food Inspection Agency to investigate potentially exposed cattle and regulated products. This was the first identification of BSE in the U.S.