BILLINGS, Mont. (AP) — A new report says the creation of an animal disease zone around Yellowstone National Park is saving cattle producers elsewhere in Montana between $5.5 million and $11.5 million annually in avoided costs for disease testing.

The Montana Department of Livestock report, issued Friday, says only 3 percent of the state's 1.4 million cattle are within the zone created last year to manage the disease brucellosis.

State veterinarian Marty Zaluski said that without the zone, federal officials would be more likely to revoke Montana's brucellosis-free status. That would bring on stricter livestock export requirements including blood tests on hundreds of thousands of Montana cattle.

Brucellosis causes pregnant animals to prematurely abort their young. It has been largely eradicated in livestock, but persists in the Yellowstone region's elk and bison herds.

Blood tests on cattle within the disease zone are projected to cost about $430,000 a year, half of which is covered by fees on livestock producers statewide. Fifteen cattle herds in Wyoming, Idaho and Montana have been infected with the disease since 2000.

State Sen. Debby Barrett, who requested Friday's cost-benefit study, said it failed to account for the stigmatization of cattle producers who live inside the zone, which lowers the price buyers are willing to pay for their animals.

The Dillon Republican and other lawmakers are backing a bill now before the Legislature to require more widespread brucellosis testing on elk — and the removal of those that test positive.

"You have to address the disease. And if the disease is in the wildlife rather than the livestock, you better address it there," Barrett said.

The Montana Department of Fish Wildlife and Parks last week announced that 12 of 100 elk in the Ruby Valley in Madison County tests positive for exposure to brucellosis. Brucellosis had not been previously recorded in the area, which is outside the designated disease zone.

Zaluski said it was likely the zone would be expanded to account for the new information, but the timing was uncertain.

Copyright 2011 The Associated Press.