Here are the Facts: Bighorn Sheep vs Domestic Sheep

This morning the Idaho Statesman published the view of Margaret Soulen-Hinson, the President of the American Sheep Industry Association. The letter was a response to a letter submitted to the Idaho Statesman co-signed by John Gale, National Wildlife Federation; Rob Fraser, Idaho Wildlife Federation; Craig Gehrke, The Wilderness Society; John Robison, Idaho Conservation League; and Jennifer Schemm, Hells Canyon Preservation Council, as well as comments that I’ve made here and elsewhere.

In the piece, which she titled “Woolgrowers want fact, not emotion” she takes issue with the idea that domestic sheep are “disease ridden”, a term that I used here and in comments to articles and letters written about the issue. I use that term because it’s true, virtually all domestic sheep carry parasitic bacteria, and other life forms which cause disease in themselves and other animals, particularly bighorn sheep and probably in mountain goats as well. It has been shown over and over again that bighorn sheep die when they come into contact with domestic sheep. Virtually all domestic sheep are carriers of Mannheimia haemolytica, Bibersteinia trehalosi, Pasteurella multocida, and Mycoplasma ovipneumoniae. All of these pathogens have been implicated in bighorn sheep die-offs but Mannheimia haemolytica has been unequivically shown to be transmitted from domestic sheep and to then kill bighorn sheep in a study where the bacteria were tagged with a plasmid carrying the genes for green fluorescent protein and ampicillin resistance.

She then goes on to quote “one prominent researcher” who said that:

“Transmission didn’t occur between domestic and bighorn sheep maintained at a distance of 10 meters for one month. … Transmission but not clinical disease occurred when these same groups were maintained with fence line contact for two months.”

This same researcher has made the assertion that:

“Transmission under range conditions is complex, experimental conditions shows that fence line contact for 2 months didn’t lead to disease, disease development required 2 to 9 days of commingling.”

This seems to contradict the statement in the study which says:

“It is conceivable that the bighorn sheep that acquired the tagged M. hemolytica during the fence-line contact would have died even without commingling with the domestic sheep. This notion is supported by the fact that one bighorn died only 2 days after commingling with the domestic sheep. However, in order to determine with certainty whether fenceline contact is adequate for induction of pneumonia and death of bighorn sheep, the experiment would need to be performed with a longer period of fence-line contact.”

The notion that it “required 2 to 9 days of commingling” was not tested in this study. The study only confirms that transmission can occur when bighorn sheep and domestic sheep share a fenceline and when they commingle. It did not seek to determine the length of time required for transmission to occur and disease and death to ensue but the results of the study seem to indicate that even if commingling took place for even a short period that disease and death ensues within 2 to 9 days.

What is at issue here isn’t whether domestic sheep can transmit deadly pneumonia in open range conditions, but, rather, what the risk is that domestic sheep will transmit deadly pneumonia to bighorn sheep in open range conditions. Frankly, this scenario has played out over and over again in open range conditions and a population of what used to be up to 2 million bighorn sheep has been reduced to 30,000 nationwide. In Idaho the population has been reduced to half of what it was in the mid 90’s to just 3,000-3,500 bighorn sheep statewide. One of the populations, the central Idaho population, consists of native bighorn sheep. This population, even though it is somewhat isolated from domestic sheep has still undergone steep declines due to diseases found in domestic sheep. While this population isn’t undergoing an all age die-off like some other populations are currently seeing, it still suffers from extremely low lamb recruitment as a result of previous disease events and could, over the long term, be doomed to extirpation because the population is unable to replenish itself. Many of the bighorn in this population are older survivors of the previous disease outbreak and carry diseases which their lambs cannot survive. The effects of any outbreak of disease can persist in a population for a decade or more.

The same problems are occurring with the reestablished bighorn sheep population in Hell’s Canyon, while these sheep are giving birth to a good number of lambs each year, an unsustainable number those lambs are succumbing to pneumonia carried by bighorn sheep as a result of previous disease transmission events from domestic sheep. They aren’t able to replenish their population at a sustainable rate to maintain their population. If another disease transmission event were to occur then this population would almost surely suffer from an all age die-off and drop to even lower levels and the cycle of low lamb survival rates would persist even longer.

The Western Association of Fish and Wildlife Agencies (WAFWA) recommends a 9-mile separation between bighorn and domestic sheep to prevent the transmission of deadly domestic sheep diseases. Some question this recommendation but even this is a compromise. It is based on the behavior of ram bighorns who tend to disperse long distances (up to 45 miles) outside what is considered core bighorn habitat in search of ewe groups. These rams often return to the core areas that they left in search of a mate to mingle with the herds of bighorn. If they happen to come into contact with domestic sheep, which they have an affinity for, they can easily spread the disease they contract to other bighorns in the herd. The disease then can rapidly spread causing an all age die-off which can kill up to 95% of a herd.

Additionally, the woolgrowers and their allies seem to clearly not accept the germ theory of disease which has clearly been validated since the 19th century. They try to insinuate that many of the disease outbreaks seen among bighorn sheep appeared out of nowhere and that domestic sheep were nowhere near the outbreaks. This is simply not the case.

A case in point that the woolgrowers point to on a regular basis: they say that there was no documented commingling of domestic sheep and bighorn sheep during the 2009/2010 outbreak. This is false, there was documented commingling between the two species according to a report by Western Association of Fish and Wildlife Agencies, Wild Sheep Working Group, and in all of the outbreaks there were domestic sheep in close proximity to the impacted bighorn populations which I summarized in this post of March 29 of 2010: WAFWA report summarizes pneumonia outbreaks in bighorn sheep.

The letter goes on to professes that the sheep industry is galled that, what they term as an agreement from 1997 (which should more appropriately be called a letter) was not followed. They believe the letter gives the sheep industry immunity from any consequences if disease transmission were to occur between domestic sheep and bighorn sheep in Hell’s Canyon. The courts have held that this letter is not enforceable because it violates the National Forest Management Act (NFMA) requirement of the US Forest Service to maintain the viability of bighorn sheep within its purview. The letter was signed by representatives of various groups and agencies who did not have the authority to make such an agreement. To depend on this letter to would be analogous to me depending on a letter from a bank branch manager stating that I could have all of the money in the bank without the approval of the bank president or its depositors.

The sheep industry and Representative Simpson claim that his bighorn rider is just a way of getting people back to the table to develop a plan more amenable to the sheep industry. We have tried that over and over again while the sheep industry denies that there is a problem and gets their pet legislators to throw obstacles in the path of collaboration.

To them collaboration means that everyone throws out science and the law and gives them everything they want. That is simply not acceptable. When the collaborative group formed at the request of Governor Otter in Idaho, one of the ground rules was that disease issues could not even be discussed. When bighorn advocates protested this, the collaborative group dissolved for a period. The collaborative group was then reformed but, when it became apparent that the sheep industry wasn’t going to get everything that they wanted, Idaho State Senator Jeff Siddoway, a woolgrower himself, introduced legislation that undermined the collaborative group. While the legislation ultimately changed before it was passed and signed by the Governor, the effect was the same, it undermined the collaborative efforts of the group and tried to give the sheep industry a pass on the issue. Ultimately the collaborative process failed because the woolgrowers failed to accept that domestic sheep can, and do, transmit deadly pneumonia to bighorn sheep.

The sheep industry also claims that the bighorn rider will give scientists time to develop a vaccine to solve the problem of disease transmission between the two species while the scientist, Dr. Subramaniam Srikumaran, a researcher working at Washington State University, says that a vaccine that would be practical for use in wild sheep wouldn’t be ready for at least 10-15 years. That timeline is far too long to realistically stem the declines seen in our bighorn sheep herds.

It is true that I am hopeful that the US Forest Service and BLM will finally develop a policy which restricts domestic sheep grazing across millions of acres of public land and stops putting Idaho’s and the nation’s bighorn sheep in jeopardy. I’m sorry that the sheep industry feels they have to depend on America’s public lands to survive but so do our bighorn sheep and they are suffering far more than the sheep industry that feels entitled to vast taxpayer subsidies.

I am galled too, I am galled by the amount of subsidies these people receive while everyone else is asked to do away with the Medicare and Social Security that they’ve paid into all of their working lives. They receive taxpayer subsidies for sheep meat, wool, and for grain they grow to feed to their own livestock; then they get practically free grazing fees at $1.35/month to graze 5 ewes and their lambs on public lands while the going rate on private lands in Idaho is $13.00 for the same; they also don’t have to pay their herders a decent wage because there is a special program that allows them to hire immigrant workers for just $750/month; they also get the taxpayer subsidized predator killing services of USDA Wildlife Services who preemptively kills thousands of coyotes, hundreds of wolves and other predators to protect domestic sheep and other livestock; and to top it all off they have a congressman willing to write a special law to benefit just them while bighorn sheep continue to die.

It’s time that the domination of public lands and wildlife by a small private industry be put in check. It’s time for the USFS and BLM to consider the welfare of bighorn sheep and make sure that disease becomes an issue of the past on public lands. If that means closing large tracts of lands to sheep grazing then so be it.

Soulen Livestock Co received payments totaling $1,246,818 from 1995 through 2010


  1. DB Avatar

    The Payette NF decision to reduce domestic sheep grazing was not based on emotion but on five years of scientific inquiry, public involvement and sophisticated environmental analysis. The shame is Simpson’s undoing of this site-specific decision for apparently political reasons.

    1. Ken Cole Avatar

      Yeah, that’s another thing that I forgot to mention in this piece. The bighorn rider DOES overturn the Payette Decision despite the false claims made to the contrary. Throughout this whole process there has been nothing offered on behalf of the sheep industry. They just want bighorn sheep advocates to equivocate and give them everything they want whenever they want.

  2. jdubya Avatar

    Well first of all mammals are “disease ridden”. Every species tested is capable of carrying, asymptomatic, a population of bacteria/viruses that are, in a susceptible member of the same species, capable of morbidity and mortality. This is taught in Med school 101 and I would assume the same in vet schools.

    Second, what the hell is “fence line” contact? When the domestic and wild sheep mingle in the wild, public lands, do the sheepherders keep a stand of barbed wire up between them? If not, then what the hell were they doing in “testing” such an experiment? Shitty science gives shitty results… what a new concept!

  3. Larry Thorngren Avatar

    How much money did the various woolgrower groups give to Simpson to get him to support their views?
    I think the Idaho Welfare Woolgrowers are quick to share some of the subsidy money they get from the rest of us with their favorite polititians.

  4. Ken Cole Avatar

    I don’t see the sheep industry as one of his top donors but the National Cattlemen’s Beef Association is #3

    1. Ken Cole Avatar

      That was just 2012

      Here is the giving by them in 2010

      $1500 to Simpson

    2. Ken Cole Avatar

      Going back through the years it appears that they loved Larry Craig.

      1. skyrim Avatar

        ….. and he loved them (and some of the sheep) right back. Bet Larry has some interesting sheep stories from being out “on the range”

  5. B Avatar

    Thanks, Ken, for the update and information. Good job.

  6. Bighorn Hunter Avatar
    Bighorn Hunter

    Simpson’s rider may not overturn the Payette’s decision, but it does eliminate federal funding for current research efforts on the Salmon River for 5 years. A large percentage of the budget for Bighorn research comes from the Forest Service and BLM. Federal land management agencies are obligated to manage for native species, it’s that simple! If this rider passes, say goodbye to Bighorn research on The Salmon…and to the Bighorn sheep themselves.

  7. Bighorn Hunter Avatar
    Bighorn Hunter

    Here’s a link to ICL’s petition. If you enjoy seeing Bighorn sheep, I suggest you sign it and forward it to others. The Senate hasn’t voted yet so it’s not too late!

  8. Barb Rupers Avatar
    Barb Rupers

    From Farm and Ranch News Volume 19, number 6, November/December 2011 “Idaho Sheep, Lamb Growers Report Healthy Revenue”

    Idaho sheep producers made more money in 2010 than in any year since 1984. Receipts last year were 38% above those of 2009. The number of lambs was 6% above the prior year.

    A veterinarian and a Wool Grower Association member from Buhl, Barry Duelke, said the industry faces challenges from more predators, federal policies, and public land issues. Also domestic sheepherders are hard to find.

  9. Leslie Avatar

    Great article Ken. I was wondering: I just finished a good book by Joe Hutto called the Light in High Places. Hutto participated in a several year study in the Winds and Whiskey mountain herd with Bighorns and found that, besides pneumonia and other diseases, the young sheep are suffering Selenium deficiencies due to the acidification of the soils in these high places, from acid rain. The Whiskey Mountain herd is not even exposed to domestic sheep, yet they are having all the same problems that you mention. I did write a short review of the book on my blog (

    Wondering if you have any more info on this or even if this is even being discussed. Of course, the area they studied is adjacent to the Jonas field.

  10. AYRES Avatar

    Please write to your Idaho Senators immediately and oppose the proposed bill 1256 currently on the floor which allows another big horn sheep tag to be auctioned off at trophy hunter conventions. Other wildlife species such as moose and goat will be also be put up to auction if this bill passes. This bill undermines the North American Model of Hunting by excluding the public comment period provided by a Fish and Game Commission hearing. The Commission nor any sportsmen’s group supports the bill. Keep Idaho the last bastion for equal opportunity for hunting and oppose 1256 the “Governor’s” auction tags.


Ken Cole is a 5th generation Idahoan, an avid fly fisherman, wildlife enthusiast, and photographer. He is the interim Idaho Director for Western Watersheds Project.

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Ken Cole