October 6, 2006

 

Minnesota discovers sixth bovine TB infected cattle herd

 

 

The Minnesota Board of Animal Health announced that a cow from a farm in the state has tested positive for bovine tuberculosis (TB).

 

This meant that the state has now detected bovine TB in six beef herds. The herd in question shared fenceline with the first beef herd to test positive.

 

Bovine TB, caused by the bacteria mycobacterium bovis, is a chronic, slowly progressive respiratory disease of cattle and does not spread easily. Infected animals can infect other animals even if they appear healthy.

 

After the first TB-positive herd was identified last year, animal health officials conducted disease investigations to find other infected animals. Potentially exposed herds, including those with fenceline contact, are required to undergo two TB herd tests one year apart.

 

The newly detected sixth herd tested negative last year, but during a second round of testing in mid-September, bovine TB was confirmed in a 2-year-old cow by the National Veterinary Services Laboratory (NVSL) in Ames, Iowa.

 

Although the herd is a small operation and has had minimal animal movement, officials are tracking animal movement into and out of the operation.

 

The detection meant Minnesota would be delayed in regaining TB-free status. The state is allowed to apply for Accredited TB-Free Status only two years after the depopulation of the last infected herd.

   

Since Bovine TB is caused by slow growing bacteria with a long incubation period, it is doubly important to test high-risk herds twice, Minnesota Board of Animal Health Senior Veterinarian Dr. Linda Glaser said. 

 

The disease spreads by direct animal to animal contact and authorities would have to be sure that all of the disease would be eliminated before the state can regain its TB-free status.

 

Minnesota now has a Bovine TB Management Plan which includes testing cattle that moved to and from TB-infected herds, testing herds within 10 miles of an infected herd and TB testing in a targeted sample of cattle herds statewide.