HELENA (AP) — The state of Montana and the National Park Service say they will collect information for a possible new plan to manage bison herds at Yellowstone National Park that have long been subject to slaughter over concerns they could spread disease.

In a statement Friday, the Park Service and the state Department of Livestock and Fish, Wildlife and Parks said they will prepare an environmental impact statement before soliciting public comment on future bison management. The goal is to possibly replace a 14-year-old management plan.

The agencies are trying to conserve a viable wild population of Yellowstone bison while reducing the risk of brucellosis transmission to livestock in Montana. About half of Yellowstone’s 4,600 bison test positive for the disease, which causes pregnant animals to prematurely abort their young.

Under the 2000 agreement, thousands of bison were killed as they attempted to leave the park.  

Policies dictating the capture and slaughter of bison entering Montana were loosened under former Gov. Brian Schweitzer. But resistance to further change runs strong within the livestock industry because of fears of the disease spreading.  

Last week, state officials said they would rework plans to ease restrictions on Yellowstone bison that enter Montana after the Board of Livestock declined to act on a proposal giving the animals more room to roam.

Montana Fish, Wildlife and Parks and the Department of Livestock and presented the board with a proposal that would have allowed bison to roam outside Yellowstone year-round only if the population were reduced to 3,300 or fewer animals.

Some board members said last week that they wanted more involvement from the cattle industry and details on how much it would cost to manage the much larger landscape where bison would be allowed.

Any proposal to expand where bison can go in Montana needs approval from the Board of Livestock and Pat Flowers, the Fish, Wildlife and Parks regional supervisor for southwest Montana.