NEWS

Farms in Up North hot zone face bovine TB troubles

Keith Matheny
Detroit Free Press

A large dairy herd in Alpena County and a large beef herd in Montmorency County have become the latest found by the state to be infected with a disease that could potentially harm humans and wipe out farms: bovine tuberculosis.

The potentially devastating disease —  which also is a potential public health issue and has cost Michigan and the federal government more than $100 million to fight since the late 1990s — is persisting in the wild deer herd in northeast Lower Michigan and crossing over into cattle. And that can cause major disruptions and financial hardships on dairy and other cattle farmers because a bovine TB discovery can mean months of quarantine, testing and often euthanization of part or all of a herd.

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Though possible to be transmitted to humans, currently bovine TB is responsible for less than 2% of human TB cases in the U.S. — less than 230 cases per year nationally — according to the U.S. Centers for Disease Control and Prevention.

The location of the latest infected farms was not disclosed by the Michigan Department of Agriculture and Rural Development.

Bovine TB is a bacteria unusually persistent in deer in this area. Healthy deer are believed to contract it from eating food containing traces of an infected deer's saliva, or from shallow drinking puddles, grass or soil infected with the bacteria that, under certain conditions, can live for weeks in the environment outside of a host. Some of the deer may graze in the same locations as cattle, or are sneaking onto farms to livestock feeding and watering areas, which they then contaminate.

Jeremy Werth is a dairy farmer in Alpena County's Wilson Township, within the remaining, four-county hot zone for bovine TB of Alpena, Montmorency, Oscoda and Alcona counties. Cattle farms in these areas must undergo annual whole-herd testing for bovine TB, conducted by state agriculture officials.

That testing on Werth's farm revealed bovine TB-infected cows in April 2015. And that kicked off months of quarantines, re-testing, and, ultimately, the killing of his entire herd of 650 dairy cows. Only now, almost two years later, is the farm returning to close to its previous level of operations and revenue, he said.

"It was very stressful — for me, my family, my parents, my brother and his family, as we all farm together," Werth said.

First discovered in a lesion-covered doe harvested in Alcona County in 1975, bovine TB didn't prompt widespread state action until 19 years later, when a 4-year-old buck harvested in Alpena County — about 9 miles from where the earlier doe had been taken — also was infected.

"The thought at the time was that bovine TB couldn't establish itself in a wild population like that," said Rick Smith, assistant state veterinarian over food animal programs at the Michigan Department of Agriculture and Rural Development.

The state Department of Natural Resources began checking deer in the region for the disease.

"The more they looked, the more they found," Smith said. "And the more they found, the more the Department of Agriculture looked and found on farms."

The findings late last year of bovine TB on the Alpena and Montmorency County farms made them the 67th and 68th herds found infected with the disease since 1998, Smith said.

At one point in the early 2000s, all of Michigan's Lower Peninsula was under some level of livestock movement restrictions and deer baiting and feeding bans, as a result of the prevalence of bovine TB.

"We've made some tremendous advancements within the state — 79 counties that are now TB-free," Smith said. "We've got that core area down to the center of those four counties in northeast Michigan. It's pretty entrenched there."

Genetic data

Bovine TB used to be a much bigger problem in the U.S. The federal government instituted a program to eradicate the disease in 1917 — a time when one in every 20 cows was believed infected, and the bacteria was responsible for about 20% of all human TB cases, mostly through the drinking of unpasteurized milk.

As with humans, the disease can lie latent in a deer or other animal's body, and they will exhibit no symptoms and won't be contagious. Later, stresses can make the disease manifest and become contagious.

So why is it remaining problematic in the northeast Lower Michigan deer herd?

Genetic data shows the deer herd there likely became infected with bovine TB in the 1950s or early 1960s, said Dan O'Brien, a DNR wildlife veterinarian.

"It was in the deer probably 15 to 20 years before it was discovered," in 1975, he said. By the time a second deer was found with the disease in November 1994, "it was already well-established," O'Brien said.

Bovine TB was discovered in cattle operations and wild deer in northwestern Minnesota in 2005. But the state then took aggressive actions, including eradicating nearly all wild deer in the affected area. By 2012 — the third consecutive year of no finding of bovine TB in the deer there — restrictions were lifted.

Minnesota's experience shows the disease can be stopped in wild deer herds and from spreading onto farms if early enough action is taken, O'Brien said.

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Rounds of testing

Jeremy Werth's dairy farm in Alpena County's Wilson Township was going through its required annual whole-herd test for bovine TB in April 2015.  Staff with the Michigan Department of Agriculture inject the cows just under the skin at the base of their tail with TB proteins. If infected, the injection site becomes a red bump within two days.

Having dealt with the testing for more than a decade, Werth thought it would be just another check off the list — a day's worth of inconvenience. Then came word that he had nearly 40 cows who reacted to the test.

"Our facilities are fully confined housing; we don't do any grazing," Werth said. "We don't typically see a lot of deer around our livestock facilities. So, at first, the question was, 'Where did it come from?'"

Later inspections revealed areas where deer were coming close to the farm, and the cattle's feed source. Months later, a 9 1/2-year-old doe was shot within 100 yards of the farm. That doe tested positive for bovine TB.

The 40 suspect cows were removed from Werth's farm and taken to a Michigan State University laboratory where they were humanely euthanized and further examined. Most had bovine TB, lab examinations showed.

Prior to 2010, the U.S. Department of Agriculture's response to such a finding was typically to have entire herds destroyed. But with the tremendous hardship that placed on farmers — even with federal compensation for their lost cows — an evolving policy was adopted that involved repeated rounds of testing, removing only suspect animals; computer modeling based on initial findings of bovine TB; and further rounds of removal and testing, while attempting to avoid whole-herd slaughters.

But after Werth's 40 cows were removed, another round of testing showed another 40 potentially infected cows.

"To lose close to 80 head in about two months, that were lactating cows, was a big blow," he said. "It impacted our milk flow; our milk shipping was curtailed about 30%. It had a large financial impact on our farm."

That summer, state and federal agricultural officials made the decision to depopulate Werth's entire 650-head herd.

"There was a heavy state of infection in the herd, and the infection was growing rapidly," he said. "The decision was to depopulate, sanitize, and let the operation sit for a vacated time. Then, bringing in fresh animals would provide a better chance of removing the TB."

Culling the herd started in October 2015, and took until the end of November, Werth said.

"The slaughtering facilities that do these animals have to do them on specific days, because they have to go through different procedures when dealing with a potentially TB-infected animal," Werth said.

Slaughtered cows found negative for TB can be processed for consumption. But any found with the bacteria, or suspected contaminated, are discarded.

Adding further complication, some of Werth's cows had given birth to bull calves. So-called deacon-calves are typically removed from their mothers, fed a milk substitute by bottles, and later sold as beef cattle.

"We had to keep our bull calves because we didn't have an avenue to sell them," he said. "Our facilities weren't designed to raise 15 deacon calves. It was a lot more work, and a lot more cost."

Though compensated by the USDA at an appraised value for his euthanized herd, Werth struggled with cash flow — an all-important aspect of farming.

"It was a huge financial setback that year," he said. After the herd was destroyed, "we had zero revenue for a little over a month. Rebuilding our new herd took us until October 2016, until we were back up to 100% production. You basically use up all of your savings and have to work with a lender to work through an operational term to get through this."

Werth and his family had operated a separate, nearby facility with about 300 cattle, to breed replacement cows for the dairy operation. After the setbacks from bovine TB, they opted not to reopen the other farm, instead buying replacement cows on the open market.

"We had to reinvest our dollars where we could see the quickest return," he said.

Enhanced security

In addition to regular testing of cattle in the four-county bovine TB zone, Michigan agricultural officials are emphasizing enhanced biosecurity on farms, keeping infected deer away.

"There are some farms around here that are starting to look like a jail — 10-foot, 12-foot fences all around them," said Galen Schalk, a farmer in Hillman in Montmorency County.

Werth's farm now includes an 8-foot fence around nearly 10 acres of feed and animal storage, he said.

State agricultural officials consider one key goal accomplished: Preventing Michigan's strain of bovine TB from spreading to other parts of the country.

"On the agriculture side, our emphasis is maintaining our surveillance program, to make sure we find it early and it's not leaking out," Smith said.

Years of feeding and baiting bans, to limit bringing sick and well deer together nose-to-nose, have not abated the more than half-century, endemic problem of bovine TB in northeast Michigan's wild deer.

"What we're finding is, the prevalence of infected deer is probably higher than we are aware," Werth said. "Not a lot of deer heads are turned in (by hunters), compared to the mountain of evidence available from the whole-herd cattle testing.

"Just like with my cattle herd, the only way to truly know what the prevalence is, is to destroy all of the animals."

But the public support for such a move — and therefore the political will to do it — isn't there.

"If getting rid of TB is a high enough priority for us — particularly for leaders in the state — that we're willing to accept the consequences of doing the things we have to do to get there, the answer would be yes, it could be eradicated," O'Brien said.

"It becomes an issue of, is what those farmers want important enough to pass regulations that are going to upset all of the hunters who hunt in the area, or those who benefit from deer hunting in the area? Is it a sufficiently high enough priority for the state that we are willing to do those things, knowing those things are not going to make people happy?"

Contact Keith Matheny:  kmatheny@freepress.com. Follow him on Twitter @keithmatheny.

Staff with the Michigan Department of Agriculture and Rural Development conduct tests on cattle at a northeast Lower Michigan farm, to determine if they've been infected with bovine tuberculosis.