Concerns for Big Game Disease

February 20, 2009 by  

By Doug Leier

Cattle diseases are now becoming problematic on big game

Cattle diseases are now becoming problematic on big game

A few weeks ago, top officials from North Dakota’s game and fish and agriculture departments attended a public meeting in Grygla, Minn., to get an up-close look at the fall-out from the increasing presence of bovine tuberculosis only 50 miles from North Dakota’s border.

Area meetings took place because bovine TB has been identified in four new cattle herds in northwestern Minnesota, since October of 2007. This development further threatened the herd health status for Minnesota’s cattle industry, and adds considerable inconvenience and expense for cattle producers.

“Of course North Dakota producers closest to that area are a little concerned because it is in the northwestern part of Minnesota, right across from our border,” said Dr. Susan Keller, State Veterinarian for the North Dakota Department of Agriculture.

The North Dakota Game and Fish Department is equally concerned because bovine TB is not just a cattle disease. It can also infect deer, and once the disease is established in a wild deer population, it is very difficult to eliminate. And if it’s not eliminated from wildlife populations, it will always be a threat to cattle and wildlife.

Minnesota was considered free of TB until it was detected in a Minnesota cattle herd in 2005. The disease is caused by a bacteria and is spread through mucous or nasal secretions, saliva, urine, milk and even manure, according to Dr. Keller.

It could be spread by direct contact with another animal, or through contaminated feed. One factor that promotes the spread of TB is that in cattle and deer, symptoms are slow to materialize. An animal could have the potential to spread the disease for many months before a producer would notice anything is wrong.

By itself, TB is not a major concern within a wild deer population. It is not usually fatal to infected deer, and is not a risk to humans as long as meat is cooked thoroughly and the deer are handled with normal precautions. In Minnesota, only a small percentage of the thousands of deer killed and tested in the TB zone actually had the disease.

But it only takes one to elevate the risk. Once TB is detected in wild deer (elk can get it, too), they can spread it to other deer which can spread it to other cattle which can spread it to other deer and the cycle continues.

“Then it becomes what everybody is fearful about,” says Greg Link, the Game and Fish Department’s assistant wildlife division chief. “It’s a long-term, drawn out, very costly situation. That’s the kind of scenario we’re all worried about and want to prevent.”

Currently, North Dakota is free of bovine TB, and has not had a case in cattle since 1999, according to Dr. Keller. The Game and Fish Department has been testing deer killed by hunters in northeastern North Dakota since 2005, when the disease was first discovered in Minnesota. No positive results have been detected.

North Dakota would like to keep it that way. That’s why Game and Fish and the Department of Agriculture are working together to minimize the risk of bovine TB getting into the state. And if it does cross the border, whether via infected cattle, contaminated feed or wild animals, plans are in place for early detection and action

Livestock producers need to make sure they follow state Board of Animal Health cattle import requirements, Dr. Keller said, “and they also need to think about the wildlife interface whenever they’re feeding; try to do everything they can to make sure that wildlife are not either eating with their livestock, or coming up on those piles after they’ve dropped feed for cattle.”

Protecting feed sources was part of the Minnesota effort. Cattle producers in the area were asked to fence their feeding areas so deer could not get in. The Minnesota DNR also banned feeding of deer in a 4,000-square-mile area around the farms. This reduces the likelihood of disease spread between deer by eliminating the unnatural, close-contact situations that feeding encourages.

The stakes in North Dakota are high. One TB outbreak could cost state livestock producers millions of dollars. Keeping the state clean is important for the cattle industry … and for wildlife.


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