Bighorn sheep are pictured in Montana in this photograph taken on February 27, 2006 and obtained on October 2, 2010. Credit: Reuters / Ryan Hagerty / U.S. Fish and Wildlife Service / Handout

By Laura Zuckerman; editing by Steve Gorman and Greg McCune
Sat Oct 2, 2010 6:29pm EDT SALMON, Idaho (Reuters) – Across the northern Rocky Mountains, bighorn sheep are dying by the hundreds from pneumonia and alarmed wildlife officials are hunting and killing the majestic animals to halt the spread of the disease. Since winter, nine disease outbreaks across five states in the West have claimed nearly 1,000 bighorns, prized as a game animal for the prominent curled horns of the adult males, or rams. Scientists recently confirmed what they long suspected — the cause of the plague is contact between the wild bighorns and domestic sheep flocks. Putting the blame on domestic sheep has heightened a furious debate between advocates of the wild bighorns and sheep ranchers — one skirmish in a bigger war between proponents of economic interests and those seeking protection of remaining wild areas and species in America’s West. The population of bighorns has declined sharply since the settlement of the West. Fewer than 100,000 sheep are believed to roam the rugged mountain slopes today, compared with an estimated 1.2 million head of bighorn at one time. Episodic outbreaks of disease have thinned bighorn herds for years. A study published in the latest edition of the Journal of Wildlife Diseases concluded that domestic sheep were the carrier-culprits behind bighorn pneumonia epidemics. Led by a team at Washington State University-Pullman, researchers placed an identifying protein into a bacteria culture, then documented how the pathogen moved from domestic sheep to wild ones. “The study proves what a lot of us suspected all along: that domestic sheep are the biggest management challenge to the restoration of wild sheep,” said Kevin Hurley, a bighorn expert for the Wyoming Game and Fish Department and head of an interstate wild sheep task force. … To save the bighorn, wildlife agencies in several Western states where the disease has spread are killing not only sick bighorns but healthy animals that make contact with domestic flocks. “I know it sounds strange that we have to kill bighorns to save them, but we can’t allow an atomic ram to go back into the population and infect the rest of the band. It’s like gangrene — you cut off the toe to save the leg,” said Wyoming’s Hurley. …

Rocky Mountain bighorn sheep ravaged by disease