By SHELLY STRAUTZ-SPRINGBORN
Michigan Correspondent

LANSING, Mich. — Bovine tuberculosis (TB) was confirmed recently in two northern Michigan cattle herds.

State agricultural officials said the disease was found in two Alpena County beef herds in March and April during routine testing conducted by the Michigan Department of Agriculture and Rural Development (MDARD) and the USDA.
Since 1998, MDARD and USDA have detected 52 TB positive cattle herds and four privately owned cervid operations in the northern section of Michigan’s Lower Peninsula (L.P.), according to Dr. James Averill, MDARD’s Bovine TB Program coordinator. Of those, 23 are in Alpena County, which is located in the state’s modified accredited zone (MAZ).

“Whole-herd tests conducted on cattle farms in the MAZ help with early detection of where the disease is located,” Averill said.

Routine testing helps officials discover the disease early, but one infected animal can affect the entire herd. During testing, veterinarians inject a small amount of tuberculin into the cow’s tail and 72 hours later, they revisit the animals to see if the injection reacted with swelling or redness. If so, a secondary test is performed. This may be a blood or another type of skin test.
In this area, Averill said the cattle “were probably exposed to the TB due to free-ranging whitetail deer.” Both farms are quarantined and no cattle may enter or leave the premises until testing clears them, he said. Investigation is done by a team comprised of representatives from several agencies.

“We look at the farm, deer habitat and environment to get an understanding of how the farm operates and where the potential risk is,” Averill said. “We also look at cattle movement on and off the farm for the last five years. We look at cattle bought and sold to be sure they didn’t spread the disease to another farm.

“With bovine TB transmission from wildlife, testing and movement restrictions are extremely important.”

He said one of the herds identified this spring is from a small operation that predominantly raises cattle from birth to slaughter. The farm is undergoing a test and removal process and will remain under quarantine for 10 months. Animals that test positive for TB will be removed from the farm and destroyed.
The second farm is a medium-sized cow-calf operation that also sells breeding stock. “Breeding stock means it’s more difficult,” Averill said. “There are about 15 other places where cattle have gone to and may have exposed others.”
He said both farms are in close proximity to areas where TB-infected deer and cattle have been found.

Phil Durst, Michigan State University dairy and beef educator, said management practices that may help prevent the disease include safely storing feed and safely feeding and watering cattle. He suggests storing hay and other feed inside a barn or within fenced areas and allowing cattle to graze in open areas, not in the woods.

In addition, watering cattle from a tank of well water or using free-flowing natural springs is safer than allowing them to drink from a low-lying, swamp-like water source.

“It’s one thing to have cattle grazing. We can’t do much about the feed in that case and it’s a high risk factor,” Durst said. “But, we want to reduce the possibility that deer will eat stored feed and reduce the chance of deer using the same water sources we are watering cattle with.

“We need to continue doing more to reduce the possibility of deer coming to the farms – hunting pressure, reducing the habitat for them, using dogs to run them off. Anything that is going to reduce the possibility of deer coming to the farm is going to helpful in reducing the risk. By maintaining the reservoir of the disease, we are going to maintain the disease.”

The MAZ includes Alcona, Alpena, Montmorency, Oscoda and Presque Isle counties in the northeastern L.P. There are more than 200 cattle farms in Alpena County and 1,000 cattle farms in the 11 northernmost counties of the L.P.