The bovine TB challenge

Loading infected cattle
When bovine tuberculosis is found in cattle, the entire herd is purchased by the federal government and slaughtered.
MPR Photo/Dan Gunderson

When bovine tuberculosis showed up in a northern Minnesota cattle herd, state officials acted quickly to slaughter the herd and stop the disease. They believed it was an isolated case.

"The worst thing is that the public up in that area says, 'Hey, we don't want to give up feeding deer. We don't want to shoot any more deer."

It's been nearly three years since that first case of bovine TB, and last week the disease was found in a ninth cattle herd.

TB has also been found in 17 wild whitetail deer, including four killed last fall.

"With every year that we continue to find infected herds and infected deer it becomes more of a challenge," says Minnesota State Veterinarian Bill Hartman.

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"We were hopeful we would be able to go up there and eliminate the infection from the cattle rapidly and do the same with the deer. Continuing to find herds this far into it is certainly not a good thing," Hartman says.

Controlling TB in a cattle herd is less complicated than fighting the disease in wild deer.

An infected herd can be quarantined and slaughtered. Minnesota used a special hunting season and federal sharpshooters in an effort to kill hundreds of deer around farms where TB was found.

Tracking cattle
State officials carefully track all cattle that may have come in contact with a TB-infected animal.
MPR Photo/Dan Gunderson

But a recent aerial survey found the deer population in the area is nearly the same as a year ago.

Bill Hartman still believes Minnesota will eradicate bovine TB, but he says it may take longer than expected. That could mean economic challenges for the states cattle industry.

The next level of federal sanctions take effect if the state has three confirmed cases of TB in cattle in a year. Minnesota now has two cases, so if a third case is found before October, federal officials will impose additional sanctions on Minnesota.

All dairy herds would have to be tested once a year. The same rule would apply to ranchers who want to sell cattle out of state.

In addition to the time and expense of testing, other states might restrict the import of Minnesota cattle.

One option to ease the pain for farmers and ranchers is a plan to split the state into two zones. Since TB has only been found in northern Minnesota, that area would be a separate zone with more restrictions.

Infected deer lung
Bovine tuberculosis lesions from chronic infection show up here throughout the lungs and on the ribs of a wild deer.
State of Michigan

The rest of the state would be a less restrictive zone where it would be easier for farmers and ranchers to sell their animals. A split state plan would need to be approved by the USDA. A similar plan is currently in place in Michigan.

Dar Geiss operates a ranch near Pierz, Minn., and is a board member for the Minnesota Cattlemen's Association. He says farmers and ranchers want the state to have a plan.

"The uncertainty is worse sometimes than what the reality is," says Geiss. "So I think what we need to know is where we're at, what we need to do and how we can move forward and then inform the farmers and ranchers what we need to do. "

Geiss says there's disagreement among farmers and ranchers about splitting the state into two zones.

"In the end we still have to get the disease eradicated from the state, and until that's done some states won't recognize the split state status anyway," he explains. "So even if you lived in the safe zone and you wanted to send cattle into another state, you would probably still have to test your cattle. So it doesn't really help some of the producers as much as they think it will. "

Minnesota officials are convinced they can eliminate bovine TB, but it may take five or ten years.

Record keeping
Accurate records help track the spread of bovine TB from one cattle herd to another. It's much more difficult to track the spread from wild deer to cattle.
MPR Photo/Dan Gunderson

The federal government might soon raise the stakes. The USDA currently does not consider TB in wildlife such as whitetail deer when regulating the disease.

The federal agency is considering new regulations that would sanction states if the disease is found in wildlife, not just cattle.

The new regulations are in response to a TB outbreak in deer in Michigan that started nearly 15 years ago.

Michigan State Wildlife Veterinarian Steven Schmitt is a recognized expert on bovine TB. Minnesota still has a good chance to elminate the disease according to Schmitt, because he doesn't believe it's self sustaining in the deer population yet.

That means if all the infected cattle are removed, the disease will naturally die out in deer. If TB gets established in deer, the odds change dramatically.

"The six places around the world where they have bovine TB in a wildlife reservoir host, they've never been able to eradicate it from the wildlife. So it's a difficult proposition," says Schmidt.

He says to keep the disease from spreading, Minnesota will need strong support from farmers and hunters.

"The worst thing is that the public up in that area says, 'Hey, we don't want to give up feeding deer. We don't want to shoot any more deer.' That's where you have a difficult problem," says Schmitt.

Some northern Minnesota landowners oppose efforts to kill deer, a few refuse to allow federal sharpshooters on their land.

Officials believe there are only a few infected deer in the wild, but since there's no way to test the deer, the only option is killing as many as possible around farms where TB has been found.

DNR officials say a recent survey found the deer herd is about the same size as it was last year, despite efforts to reduce the population. Federal sharpshooters will spend much of February killing deer in the area where most of the infections were found.

State officials banned feeding of deer in the TB zone and say recent surveillance found no illegal feed piles.

The state is also working with farmers in the area to build fences around their feed supplies to reduce contact between deer and cattle. Ten farms will be fenced this summer, and the legislature will be asked to fund fencing for another 55 farms.

The Minnesota DNR, the stat Board of Animal Health and the Minnesota Department of Agriculture will all be asking the legislature for additional funding to expand the battle against bovine TB.