BOISE — A federal judge ruled against a bid to use a report on the risk of disease that domestic sheep pose to bighorn sheep, complicating Forest Service plans to close 61 percent of the sheep grazing allotments in the Payette National Forest.

U.S. District Judge B. Lynn Winmill didn't comment on the conclusions of the advisory committee's report, but ruled that the panel itself had been improperly formed.

The Idaho Wool Growers Association filed the lawsuit in 2008, arguing that the Forest Service hand-picked scientists who met behind closed doors to come up with opinions supporting a decision to close grazing allotments to domestic sheep.

The Forest Service denied the claims, saying it didn't establish committees but simply convened panels for discussion purposes. Neither Assistant U.S. Attorney Deborah Ferguson nor Payette National Forest Supervisor Suzanne Rainville immediately returned phone messages left by The Associated Press.

The debate between wildlife advocates and sheep ranchers has long been percolating in Idaho. Ranchers in Hell's Canyon have contended that federal wildlife managers are reneging on a 1997 deal to protect their businesses after bighorns were reintroduced to the region. Wildlife advocates, meanwhile, say they just want to provide separation and adequate habitat for an iconic Idaho animal.

Wildlife advocates contend that when bighorn and domestic sheep mix, the bighorn are exposed to pneumonia and other diseases and that because they have no immunity they die. Sheep ranchers argue that there is no definitive proof that the domestic sheep are sharing pathogens with their wild cousins, and say the bighorns themselves could be carrying the diseases and fall ill when they are stressed from drought or other conditions.

The advisory committee named in the lawsuit found that grazing domestic sheep on public land does put bighorn at risk.

In his ruling, Winmill declined to discuss the merits of the committee's report, noting simply that the process itself was flawed.

Winmill took pains to point out that his ruling was not an endorsement of the Wool Growers position on disease transmission between bighorn and domestic sheep.

Still, Stan Boyd, executive director of the Idaho Wool Growers Association, said the ruling will cause people to re-evaluate the science.

"They picked the science they wanted and ignored the other science," said Stan Boyd, executive director of the Idaho Wool Growers Association. "We just felt it was a railroad job from day one — as bogus as a $3 bill."