Updated

A Montana judge on Wednesday halted further transfers of Yellowstone National Park bison, dealing a significant blow to a government-sponsored conservation effort struggling to overcome livestock industry opposition.

The order from Judge John McKeon in Blaine County has the immediate effect of blocking the pending move of several dozen Yellowstone bison to the Fort Belknap Indian Reservation. McKeon said the animals must remain on the Fort Peck Reservation, where about 60 bison were transferred in March by state and tribal officials.

More broadly, the order blocks state wildlife officials from arranging future transfers of Yellowstone bison while a lawsuit against the program from ranchers and property rights groups is pending.

The relocations are part of an attempt to curb the periodic slaughter of bison leaving the park. But many ranchers fear the bison could spread disease and compete with cattle for grazing.

In his order for a preliminary injunction, McKeon said the potential injury to the plaintiffs in the case outweighed whatever damage the state might suffer if the bison program is put on hold.

Plaintiffs' attorney Cory Swanson said the ruling protects his clients from possible losses to their livestock operations caused by bison.

"We're happy about it and feel it protects our clients from what we felt sure were future conflicts we weren't going to be compensated for. This eliminates that danger until we can get the whole case decided," Swanson said. The plaintiffs previously dropped a request that the bison at Fort Peck be returned to the park.

Mark Azure with the Fort Belknap Fish and Wildlife Department said tribal officials still hoped to get Yellowstone bison onto their reservation but were not going to make any move until further consultation with attorneys.

The Fort Belknap Reservation is located in north-central Montana and is home to the Assiniboine and Gros Ventre Indians. Although the tribes were not named as defendants in the case, Azure said he did not want to risk compromising the state's long-term goal of moving bison onto more public and tribal lands.

"From the get-go, it's really never been about just Fort Belknap and Fort Peck," he said. "This is another bump in the road, but I wouldn't say it's the end. I don't know that we're going to stop just because of this."

Sarah Elliot, a spokeswoman for Gov. Brian Schweitzer, said in a statement that the administration disagreed with the judge's characterization of bison as a large predator, a term defined in Montana law as bears, mountain lions and wolves.

Bison once numbered in the millions on the Great Plains and played a central role in American Indian life, providing meat for food, and pelts for clothing and shelter. The animals also feature prominently in many Native American religious ceremonies.

Tim Preso, a Bozeman lawyer who intervened in the case on behalf of environmentalists, said his clients were considering an appeal to the Montana Supreme Court to get the injunction lifted.

The March 19 shipment of bison to Fort Peck came without prior public notice and during a snowstorm — a maneuver by the Schweitzer administration and tribes that was meant to get the bison to Fort Peck ahead of a possible court injunction.

Three days later, McKeon issued a restraining order that temporarily barred any more bison transfers. The plaintiffs contend that later that same day four more bison were shipped to Fort Peck, possibly violating the order.

A contempt of court motion filed by the plaintiffs over the second shipment remains pending.