Bovine Spongiform Encephalopathy (Mad Cow Disease)

Bovine Spongiform Encephalopathy (BSE), also known as mad cow disease, is a fatal neurological disease of cattle. It is one of several diseases in a group called transmissible spongiform encephalopathies (TSE) and was first identified in the United Kingdom in 1986. BSE is caused by a prion that mainly affects cattle and is spread when cattle ingest tissues from another infected animal. Infected animals do not become ill for years but once the symptoms develop, the disease is fatal.

Since the late 1990s, measures were put in place in the U.S. to prevent the spread of BSE. The U.S. Department of Agriculture (USDA) prevents importation of high risk animals and animal products into the country, the USDA Food Safety and Inspection Service regulates cattle slaughter to protect the human food supply. The Food and Drug Administration (FDA) prohibits the feeding of most mammalian proteins to ruminants to reduce the risk of disease. The practice of using ruminant protein in ruminant feed caused a significant outbreak in cattle in the U.K in the 1980s and 1990s.

In 2004, USDA initiated a two-year period of enhanced BSE surveillance to more accurately assess the occurrence of this disease in U.S. cattle. Experts evaluated this surveillance data and agreed the number of BSE-infected animals in the US was less than one infected animal for every one million cattle.

Minnesota participates in the national surveillance program and continues to test targeted cattle populations for BSE. As part of this surveillance, cattle producers, renderers, and veterinarians are asked to contact USDA Area Veterinarian in Charge (AVIC) at 1-866-536-7593 to report cattle with the following signs:

• Non-ambulatory cattle;
• Central nervous system symptoms;
• Other signs consistent with BSE; or
• Dead cattle where the cause of death or clinical signs does not preclude it from being part of this targeted population.