Montana DOL reports herd with brucellosis in Gallatin County

On Tuesday, the Montana Department of Livestock confirmed that an animal on a Gallatin County ranch in Montana’s Designated Surveillance Area had been confirmed infected with brucellosis.

The infected animal tested negative in 2021 but was tested as a “reactor” in a voluntary herd test in January. Montana Veterinary Diagnostic Laboratory pathologists removed tissue from the animal post-mortem and sent the samples to National Veterinary Services laboratories in Ames, Iowa, where the infection was confirmed by culture. The DOL quarantined the herd when the reactor was discovered and launched an epidemiological investigation.

The DOL encourages voluntary herd testing to reduce the impact of brucellosis on Montana ranchers. Annual testing reduces the spread of the disease within a herd, if infected with brucellosis, through early detection of the disease. Regular testing can also reduce the impact on neighboring herds that the DOL is also quarantining until they can prove they are free of infection through herd testing. Epidemiological testing can be impractical and incur additional costs.

“Voluntary annual herd testing can be done at a time when animals are already working, such as pregnancy checks in the fall,” says state veterinarian Marty Zaluski. “The ability to control the timing of a herd test minimizes disruption when testing is needed as part of an epidemiological investigation.”

Zaluski further praised Montana DSA growers for their high rate of compliance with brucellosis regulations.

“A robust testing program not only benefits individual operations, but protects our entire industry and our business partners,” says Zaluski.

Brucellosis is a bacterial disease that can infect humans, cattle, bison and elk and can lead to abortion or the birth of weak calves. The disease is transmitted mainly through contact with infected birth tissues and fluids. Previous cases of brucellosis in cattle have resulted from transmission from infected wild elk, as determined by epidemiological investigation that involves testing adjacent or contact herds and genetic fingerprinting (genotyping) of cultured bacteria. The source of infection in the Gallatin County herd has yet to be determined.

This is the 12th herd with brucellosis found since the DSA was established in 2010. The department previously reported an affected herd in Madison County in January 2022.

Source: Montana Department of Animal Husbandry, which is solely responsible for and fully owns the information provided. Informa Business Media and all of its affiliates are not responsible for any content contained in this information asset.