Officials give info on Blaine County bovine TB

More than 100 area residents attended a meeting in Blaine County Fairgrounds in Chinook Thursday conducted by representatives from the Montana Department of Livestock and U.S. Department of Agriculture about the recent detection of bovine tuberculosis in a cattle herd in the Harlem area.

Officials briefed the public on what they know about the disease and the situation, what they are doing about it and how this will affect area producers, finishing with a question and answer period that addressed attendees' specific concerns.

State Department of Livestock Assistant State Veterinarian Dr. Tahnee Szymanski said that bovine TB, which is caused by the bacteria Mycobacterium bovis, was relatively common in the U.S. in the early 1900s. Subsequent efforts on the federal and state levels have almost eradicated the disease, but a somewhere between six and 12 cases are still discovered every year.

The infected cow was slaughtered in Michigan at the end of July, they said, and the TB was detected through routine testing of slaughter animals. Over the next two weeks Michigan and Montana officials used the cow's ID tags and sales and brand records to trace the cow back to the producer in Blaine County.

The producer, State Veterinarian Dr. Marty Zaluski said, has been highly cooperative from the outset and testing of the herd began immediately, but the time it takes to run the series of tests and confirmations, along with some unforeseen delays at the testing lab, caused the announcement to be delayed until Oct. 8. Three additional head of cattle were found to be infected.

Testing, Szymanski said, is not a black and white process unless it's done by post mortem examination of affected organs.

The epidemiological testing process for cattle, she said, starts with a scratch test administered at the base of the tail of all the cattle in the herd older than 2 years. Three days later that spot has to be palpated for a signs of swelling at the scratch site. A reaction does not confirm bovine TB, only that the cattle in question have been exposed to some form of tuberculosis.

A second round of testing is administered to any cattle that showed a reaction to the first test. And any positive cases after the second test are purchased by the USDA and further examination is done post mortem.

DNA testing of the bacterium found in Blaine County shows that it bears resemblance to strains of bovine TB from Mexico, Szymanski said, adding that this information may or may not be helpful in tracking down how the infection came to be in the herd in Blaine County.

About one-third of bovine TB cases are traced to contact with deer in Michigan where the disease is endemic to a certain segment of the deer population, State Veterinarian Marty Zaluski said. Another third are traced to cattle coming in from Mexico and the last third are novel strains which can't be traced to a specific source.

Though the disease is transmissible between cattle and humans and other animals through respiratory exchange and through sharing of feed or water troughs, when the infection is in beef cattle, the public health risk is considered minimal, Szymanski said. Testing of slaughter animals makes transmission to humans through the food chain unlikely.

If dairy cattle are involved, though, especially those used for the sale and consumption of raw, unpasteurized milk, the threat of transmission increases and Zaluski recommended that anyone with dairy cattle that may have had contact with the Blaine County herd get their dairy cows tested.

Szymanski said she is in the process of finding contact information for and reaching out to producers whose cattle have come into contact with, who have sold cattle to or who have bought cattle from the herd with infected animals. She said, though, that they are having to go back five years so the list is long and is likely to become longer with more investigation.

They have, however, contacted all adjacent producers and discussed whether they need their herds quarantined and tested or not. And in response to questions from an attendee, they said some producers on Fort Belknap Indian Reservation have been contacted, but the bison herd is not on the contacts list unless further testing leads in that direction.

The USDA pays for and assists in administering tests they said.

Because there is no treatment for cattle with bovine TB, any producers with infected cattle in the herd can choose to have cattle tested every 60 to 90 days for about a year, Szymanski said, but under certain circumstances the choice might have to be made to depopulate the herd. If USDA has money to do so, the producer will be compensated for the animal and future loss.

Producers in the area who have not been contacted are able to sell cattle, they said, and the bovine TB status of the state and area are not affected by current circumstances or and unrelated case of bovine TB found in Madison County.

Department of Livestock Chief Executive Officer Mike Honeycutt addressed worries that this might affect cattle prices for area producers who are still looking to sell calves or culled cows said that his department will be reaching out to the pbulic and buyers to dispel any worries they might have.

People with questions or who think their herd might have a source of contact can call DOL at 406-444-2976.

Because transmission to wildlife is highly probable, DOL is working with Montana Fish, Wildlife and Parks to cull small animals from coyotes to skunks and monitor deer in the area. Fish, Wildlife and Parks will be announcing a public meeting in the near future to discuss the issue and how the public can help.