Brucellosis area expanded in Idaho, increased testing required

Nov 16, 2012

The Idaho State Department of Agriculture’s expansion of a brucellosis Designated Surveillance Area (DSA) in eastern Idaho to include Fremont County will help ensure the integrity of breeding herds in the Greater Yellowstone region, the immediate past president of the Idaho Cattle Association (ICA) says.

The region’s DSA was established in 2010 as Idaho’s first such zone to help prevent transmission of brucellosis, a disease carried by infected wildlife that causes cattle to abort their young. Cattle in the DSA are required to undergo increased surveillance testing prior to change of ownership or movement out of the area.

The last day for Richard Savage, a Hamer rancher, as ICA’s president was Tuesday, Nov. 13, when Lee Bradshaw of Caldwell officially succeeded him at ICA’s annual convention and trade show in Sun Valley, which was attended by about 300 livestock producers.

Before all of Fremont County near the Idaho/Wyoming border was added to the DSA, the area included parts of Teton, Bonneville and Caribou counties. The expansion was prompted a few weeks ago when some cattle in a herd of fewer than 100 head were found to be infected in the St. Anthony area, testing positive for brucellosis, Savage said.

The expanded DSA stretches from Rexburg to Island Park and includes the Swan Valley and Palisades areas.

“The expansion is just something we’ve been working on since last spring. It went into effect the last couple of weeks,” Savage told the Western Livestock Journal. “We’ve had a surveillance zone for several years because of ‘Bangs’ in another herd outside of the area.”

The small herd infected in Fremont County had been vaccinated and was well-managed, but still contracted brucellosis, Savage said, noting cattle and elk commingling in the outdoors poses a threat. Thirty to 35 cows may have been infected.

“Cattle and elk spend a lot of time together, which is a danger. We determined that’s what happened here. The small herd of cattle went to pasture with quite a few elk. Some of those cows came infected,” he said.

Besides this latest incident, another herd of cattle was infected about five years ago when wandering buffalo mingled with them in the Swan Valley area. “They determined each of those incidents were wildlife strain infected,” Savage said.

Savage and Dr. Bill Barton, Idaho’s state veterinarian, attended a recent meeting in Rigby with area ranchers to explain the DSA’s expansion. Another meeting is set for Nov. 28 in St. Anthony.

Barton said vaccinating cows is a good preventive measure, but it is not always 100 percent effective. If cattle are exposed to migrating elk or bison herds, ranchers should especially keep them separated during breeding season from Jan. 1 to July 15 to lower the risk of catching brucellosis, Barton ad vised.

Idaho is a mandatory brucellosis vaccination state, requiring all female breeding cattle be vaccinated between 4 and 12 months of age. If a rancher’s cattle become infected, they can no longer be sold. Establishing the DSA in eastern Idaho enables Idaho to officially remain a brucellosis-free state, Savage explained.

Brucellosis is not a problem nationwide for the livestock industry and for the most part has been eliminated, but it remains a problem for the sections of Idaho, Montana and Wyoming that abut Yellowstone National Park and Grand Teton National Park where the wild elk and buffalo roam.

“Under the rules of the zone, obviously they have to remove any infected animals, but they are allowed to keep their herd after three tests. They are able to clean up the problem and maintain their herd,” Savage said.

Because brucellosis primarily is confined to the eastern corner of Idaho, the disease is not a problem to other livestock producers statewide. “The recognition is there that as long as we have this reservoir area in elk and buffalo, the possibility exists,” Savage said, adding it is a great challenge to control the disease’s spread.

The past president of ICA estimates there are more than a million head of cattle in Idaho and 20-25 percent of them are located in eastern Idaho.

“We’re real confident we are able to maintain the integrity of herds in that area in regards to breeding cattle. The purpose of the surveillance zone is to test any cattle going in and out of there for breeding purposes,” Savage said, emphasizing the DSA has worked very well and prevented the detected brucellosis from infecting reproductive animals.

“Our intent is to maintain the integrity of our breeding herd. We’re maintaining that integrity. We want everyone to understand we’re way out front of the situation and working on it.” — Mark Mendiola, WLJ correspondent