Mohave National Preserve bighorn sheep hit by pneumonia

Suspected to have come from a domestic goat-

The entire population of bighorn sheep in the Mohave National Preserve could die from pneumonia transmitted, probably, by a lone domestic Angora goat found in the desert near where the outbreak originated.

The number of bighorn near Old Dad Mountain (200 to 300) has clearly declined and the dead bighon found test positive for a microbe that is carried by domestic sheep and goats and is 50 to 90% fatal to bighorn sheep. The bacteria that cause this pneumonia are one or more of  following: Mannheimia haemolytica, Bibersteinia trehalosi, Pasteurella multocida, and Mycoplasma ovipneumoniae

It is feared that migration of bighorn rams could infect the entire preserve which holds the majority of the desert’s bighorn.

Bighorn are absolutely intolerant of domestic sheep and goats, which carry the infectuous agents silently most of the time. It has been demonstrated that the bighorn and the domestics do not have to actually come into contact. Mere trailing of sheep or goats through bighorn country often does infect the bighorn. This connection was a one time controversial, but research at the University of Idaho proved the casual relationship.

There is no vaccine for the disease. Typically the infected bighorn are shot to prevent spread to other herds.

Pneumonia is probably the largest source of bighorn deaths in the United States.  Recently a major herd near Yakima, Washington largely died off and was shot, after, as predicted, they were exposed by domestic sheep. While a half-dozen or so are killed on highways in sporadic accidents nationwide, highway deaths hardly compare to pneumonia.




  1. timz Avatar

    While there is no vacine to prevent this can the sheep be treated. I know it would be hard and costly but worth it.

    1. Ken Cole Avatar

      There is no treatment.

  2. Ida Lupine Avatar
    Ida Lupine

    This is why I have difficulty with the concept of wildlife management. Keeping the numbers artificially low makes them only one disease or disaster away from extirpation. I don’t know why ranchers won’t take steps to cooperate to try and live with wildlife. I don’t want to think of a country with nothing but people and their cars, cattle and sheep. I do smile when I think that we’ll always have coyotes.

  3. zach Avatar

    I am waiting for rancher denial over this…

  4. mikepost Avatar

    Souther/Central California was once home to a large and vibrant wild sheep population that was in large part destroyed by market harvesting AND the large scale domestic sheep ranching that began in the early 1800’s.

    This disease transmission has been going on for over 150 years and it is troubling that there does not seem to be a building of resistence in the surviving populations.

  5. Barb Rupers Avatar
    Barb Rupers

    What may be the source of the “one angora goat” that caused this disease transmission?

  6. SEAK Mossback Avatar

    Years ago, I worked with a guy who had transferred from Cal Fish & Game in the late-1960s. He was full of stories of absurd happenings during his tenure in California that were both comical and sad. Sad because of how they portrayed the overwhelming impact of humans on fish and wildlife and their habitat, and because they highlighted the huge disconnect between the majority of the California public and nature as most of us have come to know it. In one case, an area wildlife biologist finally went postal after years of county commission meetings over deer seasons in which the institutional supremacy and idiocy of “single sex” deer management was persistently upheld — and still is today, at a huge loss in reduced hunter harvest, agricultural damage and vehicle collisions. After enduring one too many hypocritical lectures in front of the commission by a local rancher (“What this young man is asking us to do is to shoot our seed stock, and I learned in this business long ago that the last thing you ever do is kill your seed stock!”), he went out and began shooting does by the pickup load and distributing them to needy families. It didn’t take long for the hounds of hell to catch up to him, and normally you might think that such a flagrant breach of law would be grounds for both dismissal and prosecution. However, what he had done, besides stirring the anger and horror of a biologically illiterate public and political class, was to act out the secret dream of every wildlife professional in the agency. After due deliberation, he was issued a severe punishment — banishment to the Mojave Desert to conduct research on desert bighorns — a move that killed three birds with one stone (gave the appearance of substantial punishment — including banishment, removed him from the area of controversy to circumstances where he would be less likely to stir public ire, and rewarded him with the most plumb wildlife position in the state).


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

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Ralph Maughan