The Minnesota Board of Animal Health announced last week that a heifer from a farm in Beltrami County tested positive for bovine tuberculosis. Minnesota has now detected bovine TB in eight beef herds in Roseau and Beltrami counties.
The Beltrami County beef cattle herd was quarantined last year after the TB investigation revealed the owner had purchased animals from a TB infected farm. A whole-herd test was conducted and at that time, all animals tested negative. During the second, follow-up herd test conducted this fall, two animals tested suspect for bovine TB. Tissue samples were submitted to the National Veterinary Services Laboratory in Ames, Iowa and a diagnosis of bovine TB was confirmed in a 12-month-old beef heifer on Tuesday. The second animal was negative.
USDA is coordinating the details of indemnification and depopulation. State and federal officials have already begun tracking the movement of animals into and out of this operation.
Minnesota Board of Animal Health Executive Director and State Veterinarian Dr. Bill Hartmann said the new finding may be explained by the way bovine TB spreads and develops.
"Bovine TB is caused by slow growing bacteria with a long incubation period. That is why it is so important to test high-risk herds twice," said Hartmann. "Due to the nature of the disease and the way in which it spreads by direct animal to animal contact, we need to be sure that we have found and eliminated all of the disease. Finding another positive herd will reset our timeline for regaining status, but for the sake of Minnesota's cattle industry, we cannot leave a single infected herd undiscovered."
In addition to traces and area testing, the state is conducting TB testing in cattle herds statewide. This statewide TB surveillance began prior to the discovery of this infected herd and is expected to be completed by the end of the year. So far, the state has tested approximately 1200 herds, with a goal of 1500. Thus far, all statewide surveillance herds have tested negative for bovine TB.
The Minnesota Department of Natural Resources plans to continue testing hunter-harvested white-tailed deer in the affected area of northwest Minnesota this fall. More than 2,000 deer have been tested in this area since 2005 and 13 deer have tested positive for the disease. All TB-positive deer were found in a small, localized area within 5 miles of Skime. DNR plans to collect additional samples this fall during the November firearm-hunting season.
"It's critical that hunters participate in this effort by voluntarily allowing their deer to be sampled," said Michelle Carstensen, DNR wildlife health program coordinator. "DNR is committed to fully cooperating with the Board of Animal Health and USDA in efforts to regain Minnesota's TB-Free status as soon as possible."
For more information, call the Minnesota Board of Animal Health Bovine TB Hotline at 1-877-MN TB FREE (668-2373). Additional details on the state's TB investigation, the disease, and the Board are available online at www.bah.state.mn.us.