Bison Yellowstone File

A bison looks up from grazing Wednesday evening, off of U.S. Highway 89 in Yellowstone National Park.

Yellowstone National Park can now officially move forward with a program to send disease-free bison to join other herds around the country.

A regional official with the National Park Service has officially signed off on Yellowstone’s quarantine program, a process of isolation and testing to certify groups of bison as free of brucellosis, a disease that can cause animals to abort. The disease-free designation allows bison to be moved more freely.

Under the approved plan, bison would undergo serial testing at corrals in Yellowstone or at U.S. Department of Agriculture corrals near Corwin Springs, north of the park. Bison that test negative for brucellosis over a certain period of time would be vaccinated and held in fenced pastures for another six months or a year. If they continue testing negative, they could be released “on suitable public and tribal lands for conservation and cultural purposes.”

The program is seen both as a way to shore up other wild herds and reduce the number of animals slaughtered each year in population control efforts. In an emailed statement, Yellowstone Superintendent Dan Wenk said the park will work with state and federal agriculture officials and tribal officials to establish the program.

“Quarantine is a positive step forward for bison conservation,” Wenk said.

Final approval comes more than two years after Yellowstone proposed quarantining bison on the Fort Peck Indian Reservation. Legal and political conflict stalled that proposal.

Yellowstone is negotiating with the state and the U.S. Department of Agriculture to finalize agreements to allow male bison to go to the Fort Peck Indian Reservation after the park held and tested the animals for nine months or less.

Robbie Magnan, manager of Fort Peck’s bison program, said Wednesday that he was happy to hear the program gained approval, though he had hoped bison could arrive at Fort Peck sooner. He said the tribes will push to make that happen in the future.

“I think with this first step we can show that we can do this and the science will back it up and we can take bigger steps in the future,” Magnan said.

Several environmental groups praised Wednesday’s announcement as a step forward for bison. Bart Melton, a regional director for the National Parks Conservation Association, said in an emailed statement that the program will “support tribal conservation efforts and reduce the number of Yellowstone bison killed each year.”

“The commonsense and science-backed program will allow for a better future for these animals — one that does not end at the slaughterhouse,” Melton said.

A group of more than 90 bison are already undergoing serial testing at the park’s quarantine corrals. Some groups are also urging quarantine of 62 bison at USDA’s corrals near Corwin Springs.

Ensuring that bison are free of brucellosis before they’re released is meant to prevent the transmission of the disease to cattle. Once a major human health concern, transmission to livestock could subject ranchers to more stringent testing requirements and could create economic instability for the industry as a whole.

About half of Yellowstone’s bison are believed to have been exposed to the disease, which is passed through afterbirth. There has never been a documented case of bison transmitting the disease to cattle in the wild.

Final agreements on the process are still in the works, but the document released Wednesday outlines three phases for the program. The first consists of serial testing over eight or nine months to weed out any animals that test positive for brucellosis. Bison that test positive would be slaughtered.

Next, bison would be tested according to federal quarantine protocols, which have different timelines and requirements based on sex and age.

Animals that graduate that portion would be vaccinated and placed in fenced pastures. Additional testing would take place after six months or a year.

The plan says the first two parts would take place either inside Yellowstone or at Stephens Creek. The third could take place elsewhere, like at Fort Peck. The park is negotiating with agriculture officials to secure an agreement that would allow the second phase to happen at Fort Peck, which would mean the park could send bison to Fort Peck by the end of this year.

Michael Wright can be reached at or at 582-2638. Follow him on Twitter @mj_wright1.

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