While bovine tuberculosis (TB) remains a worldwide issue, the U.S. has seen very little bovine TB since the late 1970s, apart from Michigan’s northeastern Lower Peninsula, according to Michigan state veterinarian Dr. James Averill.
More than 60 cattle herds have been infected in this area, where the disease has a natural reservoir in free-ranging white-tailed deer. The Michigan Department of Agriculture & Rural Development (MDARD) and Department of Natural Resources (DNR) have been battling this problem together, under the oversight of the U.S. Department of Agriculture.
Noting that USDA has questioned the effectiveness of Michigan's TB program following an increase in the number of infected cattle herds, Averill said the state's TB status is in jeopardy of being downgraded, which would affect the entire state and cost the cattle industry millions of dollars.
In an editorial, Averill said MDARD, with the support of DNR, recently approved a new zoning order that updates Michigan’s cattle regulations and creates new wildlife biosecurity strategies that farmers will have to implement to minimize the risk of bovine TB affecting their herds.
Averill noted that these efforts are being combined with DNR initiatives to manage deer numbers and bovine TB in the free-ranging deer herd. While the disease trends in the center of the northeastern Lower Peninsula have fluctuated over the past 10 years, there was a significant increase in the number of bovine TB-positive deer adjacent to this area in 2017, he said.
Considering the risk of deer activity around farms, two targeted efforts are being implemented by the new zoning order to further protect the cattle industry, Averill reported. These efforts are focused on protecting cattle farms in the highest-risk area: a newly designated area called the enhanced wildlife biosecurity (EWB) area, which is located at the core of the modified accredited zone.
In the EWB area, farmers will work with a team of experts to create customized wildlife biosecurity plans based on identified risk factors on their farms, Averill said.
A complementary effort is focused on deer that have made farms — barns, pastures and other cattle areas — their home. The only viable way to protect a farm from these resident deer is to remove them and then implement strategies to discourage future deer from returning, Averill said.