BILLINGS, Mont. (AP) — Montana wildlife officials say they are seeking proposals to take up to 135 disease-free bison being held under an experimental effort to establish new populations of the animals. The small herd in the U.S. Department of Agriculture program is made up of animals captured from Yellowstone National Park and their descendants. The bison have been held for the past several years on behalf of Montana Fish Wildlife and Parks at a Bozeman-area ranch owned by philanthropist Ted Turner. They have been tested repeatedly to make sure they don't have the disease brucellosis, which can cause pregnant animals to prematurely abort. Livestock groups have opposed previous Yellowstone bison transfers. Officials say proposals to take the animals are due by April 30. They could be moved as early as November.