Several thousand head of cattle have been quarantined in Montana after a cow near Yellowstone National Park tested positive for brucellosis, the livestock disease much feared by ranchers and also carried by elk and bison, state livestock officials said on Friday.
The disruption comes at a crucial moment for the region's beef producers, who are in the midst of readying the bulk of their herds for sale at a time of record high prices for the cattle they bring to auction.
The quarantine will for the time being place off-limits livestock belonging to the rancher whose cow tested positive - likely infected by an elk - and neighboring producers whose herds may have been exposed through intermingling of livestock, officials said.
But the finding will not cost Montana its prized brucellosis-free status, which allows cows to be shipped across state lines without vaccination or testing, he said.
Several thousand head in all are affected by the quarantine, a fraction of the more than 2 million cattle raised throughout Montana, state veterinarian Dr. Marty Zaluski said.
Exposure to brucellosis, a disease that can cause pregnant cows and other animals to miscarry their young, is at the center of an ongoing dispute between ranchers in Montana and wildlife advocates over management of Yellowstone's famed bison population and vast elk herds in and around the park.
Many of those animals have been exposed to the disease, first brought to the region by cattle.
Bison that wander from Yellowstone into neighboring Montana each winter in a search for food are targeted for hunting or capture and slaughter to prevent them from transmitting brucellosis to cattle that graze in the vicinity.
The program is fiercely opposed by environmental groups and wildlife activists, who routinely sue to stop the culling.
Under a U.S. Department of Agriculture rule designed for livestock in the vicinity of Yellowstone, which spans parts of Wyoming, Montana and Idaho, testing and quarantining of cattle is required to prevent the spread of brucellosis when it is found, Zaluski said.
Cows in Montana counties just outside Yellowstone have tested positive for brucellosis just five times during the past eight years without triggering larger outbreaks or risking the state’s brucellosis-free classification.
“The infection rate is very low because we identify these cows very quickly,” Zaluski said.