ALPENA - A cow in an Alpena County dairy herd has tested positive for bovine tuberculosis, according to the Michigan Department of Agriculture and Rural Development.
The discovery was announced Friday after a cow within a herd of 50-99 cattle was found to have the bacterial disease through routine testing done by MDARD and the United States Department of Agriculture, said James Averill, MDARD animal industry division director. The herd is now under quarantine and will undergo further testing until officials are satisfied it's disease-free.
A public hearing is scheduled for July 12 in Alpena Community College at 7 p.m., Averill said. Rick Smith, who oversees the TB program, will answer questions and talk about what's ahead for the farm in question. He'll also discuss preliminary findings from an investigation of the source of the disease.
"It's just meant to be an informational hearing to let the general public know what's happening, and let them know where we are in the process," he said.
Averill said the testing had nothing to do with three deer shot in Presque Isle County in 2011, adding the herd was "quite a distance away" from where the deer were taken.
"The (dairy) herd was identified through routine whole-herd testing that we do in that part of the state on an annual basis," he said.
Alcona, Alpena, Montmorency and Oscoda counties fall within a modified accredited zone, a USDA designation that sets rules for cattle movement, identification and testing, according to MDARD.
This is the second time the farm has found a TB-positive cow within its herd, Averill said. The previous time was more than five years ago. Since then, the farm has adopted a plan to eradicate the disease within its herd. Farmers also have taken steps to keep wildlife from spreading the disease to its herd, as TB can be carried by whitetail deer and other animals.
While the farm has complied with its wildlife risk mitigation plan, these steps can only reduce - but not eliminate - the risk of wildlife spreading the disease to its cattle, Averill said.
Next week, personnel from several departments and the Michigan State University Extension will come to the farm to search for the source of the investigation, Averill said. They'll talk to the farmers and check to see if wildlife have been living in close proximity to the herd. This will include trapping raccoons and opossums on the farm. These animals serve as carriers of the disease, but are unlikely to spread it to cattle.
"Some of that information will be shared during the July 12 meeting," Averill said.
The team will continue to gather data through the month.
Cattle sold to and from the farm also will be checked to ensure TB neither originated from, or spread to, another farm, Averill said.
Fifty-four herds have been found to be TB-positive since testing began in 1998, two of which were found this year, Averill said. The latest herd is now going through a test-and-remove process, during which the herd goes through a series of tests every 60 days. If any new cattle are discovered to have TB, they'll be pulled from the milking line, euthanized and necropsied.
Tests will continue "until there's been a 95 percent confidence there's no disease in the herd, and they'll do another test six months after that," he said. "Then they'll be released from quarantine."
An alternative would be to depopulate the herd and humanely kill each animal, Averill said. It's not uncommon for dairy farmers to opt for the test-and-remove process instead.
The dairy farm still can sell milk during the quarantine, although federal rules prevent the sale of any milk from a cow found to be infected, Averill said. Any bacteria in the milk would be killed by pasteurization.
Jordan Travis can be reached via email at firstname.lastname@example.org or by phone at 358-5688.