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  1. Compliance & Enforcement

Bovine Spongiform Encephalopathy

Bovine Spongiform Encephalopathy (BSE) belongs to the unusual group of progressively degenerative neurological diseases known as transmissible spongiform encephalopathies (TSEs). TSE diseases are characterized by long incubation periods ranging from several months for transmissible mink encephalopathy, to several years for BSE. During the incubation period there is no visible indication of the disease. In the late 1980’s and early 1990s, BSE spread within the United Kingdom and then to other countries through the practice of using rendered bovine origin proteins as an ingredient in cattle feed. Since then, feed restrictions put in place by countries that may have imported infected cattle or contaminated feed ingredients have been highly effective in reducing the number of BSE cases worldwide.

In 1997, FDA published a final regulation that prohibits the use of most mammalian protein in the manufacture of animal feeds given to ruminant animals, such as cows, sheep, and goats. The rule does not prohibit the use of mammalian protein as an ingredient in feed for non-ruminants, but requires process and control systems to ensure that such use does not cause contamination of ruminant feed during feed manufacture or transport. FDA strengthened the 1997 rule in 2008 by prohibiting the use of the highest risk cattle tissues in ALL animal feed. These high risk cattle materials are the brains and spinal cords from cattle 30 months of age and older, and the entire carcass of cattle not inspected and passed for human consumption, unless the carcasses are shown to be from cattle less than 30 months of age, or the brains and spinal cords have been removed.

To date, six cases of BSE have been detected in the United States. The first case was detected in 2003 in a cow imported from Canada, diagnosed with “typical” BSE, the same strain that caused the outbreak in the United Kingdom. Five more cases have since been detected in U.S. born cattle, but laboratory evidence suggests that these cases had atypical strains of BSE, that is not the same strain that caused the large outbreak in the United Kingdom.

Please direct questions on CVM’s BSE activities to:

Division of Compliance (HFV-230)
Office of Surveillance and Compliance
Center for Veterinary Medicine
U.S. Food and Drug Administration
MPN IV Bldg., Room 146
7519 Standish Place
Rockville, MD 20855-2773
Telephone: (240) 402-7002
FAX: (240) 276-9241


Guidance Documents

BSE Video List

Additional Resources


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