The Montana Department of Livestock says a heifer from the Paradise Valley has tested positive for brucellosis. Testing performed at the National Animal Disease Center in Ames, IA, confirmed the presence of the brucella abortus bacterium, the causative agent of brucellosis. Within four to eight weeks, or as soon as soon as the downgrade can be listed in the Federal Register, Montana will be downgraded from Brucellosis Class Free status to Class A.

State veterinarian Marty Zaluski says the brucellosis-confirmed heifer had been vaccinated twice and was part of a herd-management plan. All other animals in the herd have tested negative.

With the loss of Class Free status, Montana’s livestock producers must test bulls and non-spayed females, 18 months of age or older, 30 days before interstate movement.

In May 2007, the disease was discovered in a Bridger cattle herd, resulting in 301 cows and 284 calves being depopulated. Per USDA-Animal & Plant Health Inspection Service regulations, the state had to remain brucellosis-free until July 2009 to maintain its Class Free status. Montana had been brucellosis free since 1985.

The soonest Montana can apply to regain Class Free status is one year from the date the last reactor was killed, or May 27, 2009. In February of this year, USDA declared all 50 states to be free of brucellosis in livestock, the first time in 74 years.