Infected Montana cow ends brucellosis-free status

Four months after the Department of Agriculture declared U.S. cattle brucellosis free, a Montana cow tested positive in June for the bacterial disease.

Montana state veterinarian Dr. Marty Zaluski said the loss of brucellosis-free status is particularly frustrating, given efforts by livestock producers and the industry to mitigate risks and increase disease surveillance.

"Producers in the Paradise Valley have been involved and diligent, and they have taken it upon themselves to be proactive in regard to managing the risk of brucellosis transmission," Dr. Zaluski said. "In this particular case, the owner did everything right. The cow had been vaccinated twice and was part of a herd management plan."

On Feb. 1, the USDA announced that for the first time in the 74-year history of the brucellosis eradication program, all 50 states, Puerto Rico, and the Virgin Islands had simultaneously achieved class-free status in cattle (see JAVMA, March 15, 2008).

Montana's loss of class-free status means the state's livestock producers are required to test bulls and nonspayed females, 18 months of age or older, 30 days prior to interstate movement.

The soonest Montana can apply to regain class-free status is May 27, 2009, one year from the date the last reactor was euthanized. All other animals in the herd where the positive cow was found tested negative for brucellosis.