LANSING, Mich. – Michigan officials have announced the latest finding of Bovine Tuberculosis (TB) positive cattle in the state.

The announcement was made Feb. 8, the infected animal was found in a herd in Oscoda County, Mich., which is part of the Bovine TB endemic zone. The National Veterinary Services Laboratories, situated at the Michigan State University main campus in East Lansing, confirmed the presence of the disease in one of the animals from the herd on Jan. 25. According to a statement from the Michigan Dept. of Agriculture and Rural Development (MDARD), more testing will be conducted to ensure that the remaining animals in the herd are healthy. If some are not, they will be removed. The department is currently conducting an investigation to try and determine the source of the infection.

Bovine TB is a bacterial disease that can affect all mammals, including humans. It is known to be present in the free-ranging white tailed deer population of the so called Modified Accredited Zone (MAZ), a four county area that includes Alcona, Oscoda, Montmorency and Alpena counties in Michigan’s northeastern Lower Peninsula. A major concern is that the disease is being transmitted from the free ranging deer population of the MAZ to cattle herds in that area. State and federal agencies are taking steps to control the disease in Michigan. There is an agreement between state and federal officials regarding Bovine TB that lays out guidelines the state must meet in order to keep its so called split-state status, meaning most of the state is considered Bovine TB free, while the northeastern Lower Peninsula counties in question remain under a separate category.

“We are essentially allowed to have three herds to be found TB positive in a 12 month period and still be in line with the MOU we have with the USDA,” said Nancy Barr, the Michigan assistant state veterinarian. “We aren’t at any risk of reaching the limit or violating the MOU at this time. It’s always a big deal for the producer to have a Bovine TB positive animal in his herd, but it’s not a threat to the MOU.” The herd will be tested for about 12 months following the positive test to make sure there are no more Bovine TB positive animals. During this period the herd will be under quarantine, which means no animal in the herd can be moved out or sold and no animals can be brought in. The TB positive animal is euthanized. 

It’s important to understand that Bovine TB is transmitted when free ranging white tailed deer come into direct contact with cattle, or with cattle feed. The producer in question did have a wildlife risk mitigation plan in place, which means he was taking steps to keep white tailed deer away from his herd and from feed, Barr said. Such plans commonly include the use of fencing to keep deer out; the exact requirements of such plans depend on exactly there the herd is located. If it is in the state’s “Enhanced Wildlife Biosecurity Area,” then a wildlife risk mitigation plan will be more stringent. “Overall, our Bovine TB programs are working well,” Barr stated. “We’re always working to improve our Bovine TB mitigation programs. Our big spillover almost always comes from the free ranging deer herd, not the privately owned cervid farms.”

At one time a Bovine TB positive animal in a herd required the depopulation of the entire herd, but that is no longer the case, Barr said. The reason for this is the lack of funds available to compensate the producer for his losses. Instead, MDARD will monitor the herd in question with sample testing over a period that could last several months, to ensure that no other animals are infected. If other TB positive animal are found during this time, then they are removed from the herd, also, and the testing period for the rest of the herd is extended.