Enhanced Wildlife Biosecurity: An Evolving Tool vs. TB
by James Averill, Michigan State Veterinarian Since 1994, MDARD has worked with the USDA’s Bovine Tuberculosis Eradication Program to use every available resource to prevent the spread of bovine TB from the free-ranging deer to Michigan cattle herds. (Photo courtesy of Square cow movers)Dairy and beef farmers throughout the state face many different challenges while managing their operations. However, those in the northeastern Lower Peninsula of Michigan (Alcona, Alpena, Cheboygan, Montmorency, Oscoda Otsego and Presque Isle) have the added challenge of protecting their cattle from bovine tuberculosis. Bovine TB is a bacterial disease that can infect cattle and is found in the free-ranging white-tailed deer herd in that part of the state. Since 1994—when bovine TB was identified in a Michigan deer—the Michigan Department of Agriculture and Rural Development (MDARD) has worked with the USDA’s Bovine Tuberculosis Eradication Program to use every available resource to prevent the spread of bovine TB from free-ranging deer to Michigan cattle herds. Although the national program sets the guidelines for bovine TB eradication nationwide, Michigan’s unique situation of having the disease move throughout a wildlife population posed an entirely new set of challenges. That is why, for more than 20 years, MDARD has worked with the USDA to develop and refine Michigan-specific programs that strengthen the state’s ability to prevent bovine TB and ensure animals can be tracked and identified when an infected farm is found. One of the tools MDARD continues to use on farms in the northeastern Lower Peninsula is the Wildlife Risk Mitigation (WRM) project. WRM uses the latest research on how bovine TB is spread and how deer move to create a set of basic guidelines for preventing contact between cattle and deer. The WRM program is intended to change cattle management practices that make it easier for bovine TB to be transmitted from infected deer to cattle herds. Examples of these changes include the following:
Moving cattle and cattle feeding areas away from deer habitat and to more protected areas.
Limiting the amount of feed put out for cattle to an amount they can rapidly consume (so no feed is left for deer to contaminate).
Providing flowing or natural water sources that are less likely to serve as a source of infection.
Making stored feed less available to deer by moving it away from deer habitat and protecting it by fencing and other methods.
Although the changes made by farmers through WRM have reduced the risk of cattle becoming infected with bovine TB, there is a portion of the northeastern Lower Peninsula where these measures do not go far enough. The risk in this area, in and around Deer Management Unit 452, is much higher than for the remainder of affected counties in the northeastern Lower Peninsula. In and around DMU 452, the prevalence rate in deer is more than 10 times that of the lower-risk areas. In this high-risk area, bovine TB is continuing to move from the free-ranging deer to cattle, and poses an ongoing risk to the almost 120 cattle herds located there. The reoccurrence of bovine TB in this area is not only devastating to the families involved, but it’s also possible that, prior to a herd being identified as infected, animals may move and infect other farms, which has happened three times since 2016. To prevent more infection in this high-risk area, MDARD—in cooperation with Michigan State University Extension, Alpena-Montmorency Conservation District, the U.S. Department of Agriculture Wildlife Services and local producers—is working on a new voluntary program to address these concerns. Enhanced Wildlife Biosecurity (formerly known as Enhanced Wildlife Risk Mitigation) is a farm-specific approach that involves a team of experts who evaluate a farm’s practices. This new approach includes analyzing how deer are moving around and on the farm and helps the team develop specific recommendations aimed at keeping the farm protected from bovine TB. The long-term goal of the program is not only to protect the farm, but also to help the farmer understand how deer move around their farm and how to take additional precautions to prevent bovine TB infection. The team works year-round with the farmer, since deer habits and the risk of bovine TB change with the seasons and can vary from year-to-year. Additionally, the project is taking a community-based approach by having the team work with all the cattle farms in a community so they are each working toward protecting their farms together. Bovine TB has been present in the free-ranging white-tailed deer herd for many decades, and the risk of cattle becoming infected from bovine TB will not go away anytime soon. The best way to have a thriving Michigan cattle industry is to prevent contact between bovine TB-infected deer and cattle herds. This requires that we not only maintain the bovine TB prevention practices that have been put in place in the northeastern Lower Peninsula, but also begin the farm-by-farm battle in the highest risk area to keep our cattle and farms safe.