After six years, bovine spongiform encephalopathy (BSE) has again been discovered in the U.S. cattle herd.

A dairy cow in central California dairy was recently diagnosed with BSE, commonly called mad-cow disease, according to USDA Chief Veterinary Officer John Clifford.


The carcass of the animal is being held by the state of California at a rendering facility, where it will be destroyed.  In a statement issued Tuesday, Clifford said the animal was never presented for slaughter as food for human consumption and that BSE cannot be transmitted via milk.

For those reasons, Clifford said “at no time” did the animal present a risk to the food supply or human health.

California joins Washington state, Texas and Alabama in experiencing the discovery of a mad cow within its borders. BSE is called mad-cow disease because it is a brain-wasting condition that can be transmitted to humans from eating beef that contains bits of the brain, spinal cord or digestive tract from infected cattle.

The first BSE-infected cow in the U.S. was found near Mabton, WA on Dec. 23, 2003.  Two others were discovered later, one in Texas in 2005 and another in Alabama in 2006.   

USDA’s National Veterinary Services Laboratories confirmed the California dairy cow was positive for atypical BSE, a very rare form of the disease that the department said is not generally associated with an animal consuming infected feed.

USDA does not expect the discovery of a fourth mad cow to change its BSE status under the World Animal Health system; Clifford said this detection should not affect U.S. trade.

Worldwide, there were 29 BSE cases in 2011, a 99 percent reduction since the peak of 37,311 cases in 1992. Clifford attributed the dramatic decline to feed bans as the primary control measure.