A brucellosis-positive cow was found in Montana’s Gallatin County, triggering a quarantine and investigation.

A brucellosis-positive cow was found in a Gallatin County herd in Montana on December 24, 2025, the second case in the state this year. The animal was identified during voluntary fall testing and removed before calving, preventing spread. The herd is quarantined, and an investigation is underway, limited by minimal contact with other herds and annual testing. All prior 14 cases in Montana were linked to wild elk in the Greater Yellowstone Area. The state continues efforts to maintain brucellosis-free status for livestock trade.