Preliminary tests indicate that 13 more cattle from a western Wyoming herd may be infected with brucellosis, dampening hopes that the disease may be contained to a single herd.

Two cattle from the rancher's separate purebred Angus herd were determined earlier this month to have the disease, which can cause pregnant cows to abort their young.

The remaining 250 or so Angus cattle will be tested next week, Logan said. Once the entire herd is tested, the state will begin testing surrounding herds belonging to other ranchers.

Wyoming is in danger of losing its brucellosis-free status if the disease is found in another herd or if the Daniel rancher declines to slaughter his entire herd.

"It's really a fairly clean herd but we do have more than just the two that were initially found," he said.

If the state loses its brucellosis-free status, Wyoming would have to impose costly testing requirements for all cattle in the state that are sold or moved to another state.