BILLINGS, Mont. (AP) Tests on about 3,000 Montana cattle have turned up no additional cases of the livestock disease brucellosis (broo-suh-LOH'-sis), that showed up last May in a herd near Bridger.

Montana livestock officials say some testing will continue; but they say the results announced today offer strong evidence that the brucellosis was limited to a single herd.

Montana cannot have any additional cases of brucellosis for at least two years after the initial infection, or it could lose its federal disease-free status.

That would force ranchers to undergo a costly vaccination program, and possibly damage the reputation of Montana's cattle industry.

Brucellosis causes pregnant cows to abort their calves. It has been wiped out across most of the country; but persists in bison, elk and other wildlife around Yellowstone National Park.

(Copyright 2007 by The Associated Press. All Rights Reserved.) APNP 12-19-07 1457CST | save this article / add to your favorites list