HELENA, Mont. (AP) – The livestock industry's concern over the threat of disease spreading from wild bison to cattle has helped advance about a dozen bills restricting the movement of the animals as the legislative session breaks to transfer bills between both chambers.

Those who want to see the bison reigned in say the animals are transmitters of brucellosis and a threat to the disease-free status of the state's livestock industry; a certification that if lost could cost millions of dollars.

A vocal minority has opposed the measures, saying the bills threaten the wild bison's natural place in the state's habitat and jeopardize the animal's special relationship with Indian tribes.

The bison bills advancing in the legislature range from establishing local authority over the transfer of wild bison across county lines to prohibiting free-roaming bison altogether.

Large groups of bison periodically migrate out of their designated habitat and the deliberation over how to treat the wayward animals, possible slaughter or relocation, has stirred public debate.

State and federal agencies have experimented with new ways of returning wild bison to different locations across the state. Their relocation programs have only been moderately successful, and a permanent plan for the bison population has yet to be determined.

If the more restrictive bison measures are signed into law, it would could effectively block such park service experiments with relocations in the future.

Sen. John Brenden, who is sponsoring a number of the bison bills this session, said the risk of a brucellosis outbreak is just too high to justify trying to relocate and expand the herds.

“Because our livestock industry is so big as far as an economic power the threat of brucellosis is something we can't afford,” the Scobey Republican said.

There has been no documented case of a bison transferring the disease, which causes animals to abort their young.

Brenden said the animals also are so hard to control that there is no room for free roaming bison in a modern society.

“If we start spreading and disseminating buffalo all over the state of Montana I think that creates a bigger problem and I don't think it matters if it's on a reservation or any other place, your just opening up yourself for more liability,” he said.

The American Indian Caucus sees the issue differently. Some Indian reservations already have buffalo herds on their land and others are calling for expanded populations of the animals.

Sen. Sharon Stewart-Peregoy from Crow Agency said having herds of wild bison is important because of the ceremonial and religious role the animal plays in tribal culture.

She said the measures in the Legislature violate a bison management treaty signed between the tribal nations, the state and the federal government.

“What I perceived and the American Indian Caucus perceived with these different bills was an outright piecemeal attack to that agreement and to the status of the bison,” she said.

Stewart-Peregoy and other critics of the bills say brucellosis is primarily transferred by elk, and that bison are unfairly characterized as a high disease risk.

Yellowstone National Park has one of the largest concentrations of the animals in the world, with around 3,900 genetically pure bison. Critics of the restrictive bison bills say the animals need more land to roam than just Yellowstone.

State agencies recently transferred bison from Yellowstone to a grazing area in Gallatin National Forest for the winter, and have identified several wildlife management areas as potential bison grounds.

The Gallatin National Forest program was only partially successful after part of the herd moved onto private land. The prospect of moving bison to the Spotted Dog Wildlife Management Area sparked community opposition.

The opposition led to Senate Bill 174 to prevent the relocation, which was passed by the Senate.

The bison bills must pass both houses and then sent to the governor to sign before they could become law.