BILLINGS, Mont. (AP) – A decision on a plan to relocate up to 160 Yellowstone National Park bison onto state and tribal lands has been postponed after ranchers raised objections, wildlife officials said Wednesday.

A vote by Montana's Fish, Wildlife and Parks Commission on the relocation had been scheduled for next week. State wildlife chief Ken McDonald said the vote has been postponed and it is uncertain whether the topic will be revisited in December.

The delay throws into doubt a key first step in an ambitious plan to establish new herds of North America's largest land animal outside the confines of Yellowstone.

Conservation groups back the relocation plan as a means of restoring a species that once roamed across most of North America and numbered tens of millions of animals. But ranchers who spoke at recent public hearings on the topic said they were worried about the bison damaging their fields and fences and spreading the animal disease brucellosis.

McDonald said the delay was driven by the need to review about 3,000 public comments that have been submitted on the proposal. He declined to say if most of those were positive or negative.

“There are a lot of issues being brought up in the comments that we need to develop responses to. We need some additional time,” he said.

Wildlife officials have offered four potential relocation sites that would take up to 40 bison each: the Fort Belknap and Fort Peck Indian reservations in northeast Montana and two state-run wildlife management areas in central and southwestern Montana, Spotted Dog near Avon and Marias River near Shelby.

The animals would be kept at the relocation sites until a statewide bison conservation plan was completed. Officials have said that plan is expected to be done by 2015.

In the interim, fences would be erected at the wildlife management areas to keep the bison from wandering. Fencing already is in place on the two reservations.

Yet ranchers are suspicious the temporary relocations could become permanent, forcing their cattle to compete for grazing space with free-roaming bison. Some hunters and recreational users have said they are concerned the bison fences would restrict access to the state management areas, which are populated by elk, deer and antelope.

“I think this relocation is just to jump the gun so in 2015 they can tear their fences down and say, `Now you have free-roaming bison,”' said Brian Quigley, a rancher near Avon and head of the local stockgrowers association. “It's going to take a whole lot of people to stop this.”

The relocations have been in the works for several years. Supporter Keith Aune, with the Wildlife Conservation Society, said the state had made a strategic error by waiting so long to engage the public on whether bison belong on a broader landscape in Montana.

“The state is in a tough spot, but I think this could be done,” said Aune, a former Fish, Wildlife and Parks biologist. “Part of the problem has been getting the process to work and getting information out to everybody so they understand what has been proposed.”

About 100 of the bison are being held for the state by philanthropist and media mogul Ted Turner on his ranch near Bozeman, McDonald said. Turner got the bison after earlier relocation attempts failed. He will be allowed to keep some of the bison's offspring in exchange for caring for the animals.

The remaining bison slated for relocation are in a government-run quarantine north of Yellowstone near Corwin Springs, McDonald said.

“If they are in that facility for two or three more years, there's still a need to find a place for them,” he said.