Cattle herds in NW Minn. free of bovine tuberculosis, officials say

After a six-year eradication effort, the state veterinarian says cattle herds in northwest Minnesota are free of bovine tuberculosis.

State Veterinarian Bill Hartmann said the state will apply to the U.S. Agriculture Department to be re-certified as free of bovine TB. Hartmann said the struggle with the disease began with the identification of an infected herd in 2005.

"We never did make an absolute determination of where the TB came from, and that isn't unusual really," Hartmann said. "In other states that have had a challenge with TB, it's rare that you ever find out where it came from."

He said the assumption is that the disease came into Minnesota with cattle from another state. He said the TB bacteria found in the cattle typically originates in the southern U.S. or Mexico. A total of 12 herds were infected.