BILLINGS (AP) — Yellowstone National Park is seeking public comment on a proposal to capture and quarantine wild bison so disease-free animals can be relocated to create new herds outside the park, Yellowstone officials said Wednesday.

The announcement comes after the Department of Interior last month identified 20 parcels of public lands in 10 states that could be suitable for relocated Yellowstone bison.

Yellowstone’s roughly 4,600 bison are prized for their pure genetics. But many carry the disease brucellosis, which can cause pregnant livestock to prematurely abort their young.

Thousands of park bison have been shipped to slaughter in recent years to control their numbers. Yellowstone spokesman Al Nash said a quarantine program could offer some relief for those population pressures, and simultaneously advance the restoration of bison to new areas.

The quarantine facilities could be located inside the park, on tribal lands or elsewhere, park officials said.

Public meetings on the quarantine proposal are scheduled for Aug. 18 in Gardiner and Aug. 19 in Bozeman.

Comments will be taken through Sept. 12 and used to develop an environmental study of the proposal. Nash said there is no timeline for a decision.

A pilot quarantine program that began in 2005 has had mixed success. Efforts to relocate about 200 bison that were declared disease-free have been opposed by Montana landowners and ranchers, who worry the animals could compete with cattle for grazing space.

About 60 of those bison were moved during the past two years to the Fort Belknap and Fort Peck Indian Reservations in northeast and north-central Montana. The remaining disease-free bison are being held on a Bozeman-area ranch owned by media mogul and conservation advocate Ted Turner.

Sites studied for future herds include Arizona’s Grand Canyon National Park, an Iowa wildlife refuge and a North Dakota national historic site.