Thursday, 14 February 2008 12:40

Erroneous statements concerning bighorn sheep and domestic sheep in recent news articles.

Written by Floyd Rathbun
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Two recent news articles described Nevada Department of Wildlife (NDOW) efforts to transplant bighorn sheep from one mountain range to another.  The Fallon newspaper (Lahontan Valley News, December 20, 2007) printed a story about transplanting bighorn sheep from Churchill County to Mount Grant in Mineral County. In January 2008, the Nevada Rancher news magazine printed a story circulated by the Associated Press about transplanting bighorn sheep from both the River Mountains and Muddy Mountains in Clark County to the Delamar Range in Lincoln County.

Read into the minutes of February 8th 2008 Commission Meeting...

 

FLOYD W. RATHBUN                                          (775)423-4267

CERTIFIED RANGE MANAGEMENT CONSULTANT                       P.O.BOX 1612

                                                                                                   Fallon, NV  89407

                                                                                                   This e-mail address is being protected from spambots. You need JavaScript enabled to view it

 

DATE:            February 8, 2008

 

TO:                 Nevada Board of Wildlife Commissioners

                        Ken Mayer, Director of Nevada Department of Wildlife

                        (Note this letter will be delivered rather than mailed)

 

Subject:  Erroneous statements concerning bighorn sheep and domestic sheep in recent news articles.

 

QUALIFICATIONS AND BACKGROUND OF FLOYD RATHBUN

My background includes both experience and education in Range Management and Wildlife Biology.  My professional career includes over thirty years of employment by State and Federal agencies in the capacity of Wildlife Biologist, Soil Conservationist, and Range Conservationist, mostly in Nevada.  I am currently self-employed as a Range Management Consultant. 

 

The following observations and statements are directly from the perspective of my technical and scientific background in natural resource management.  I also enjoy hunting, camping, botany, and other outdoor recreation.  As both a professional in natural resource management and as a sportsman, I whole-heartedly endorse biologically sound, rational management efforts that are designed to provide a variety of wildlife and healthy wildlife habitats:

 

INTRODUCTION

Two recent news articles described Nevada Department of Wildlife (NDOW) efforts to transplant bighorn sheep from one mountain range to another.  The Fallon newspaper (Lahontan Valley News, December 20, 2007) printed a story about transplanting bighorn sheep from Churchill County to Mount Grant in Mineral County. In January 2008, the Nevada Rancher news magazine printed a story circulated by the Associated Press about transplanting bighorn sheep from both the River Mountains and Muddy Mountains in Clark County to the Delamar Range in Lincoln County.

 

Both articles indicated that the extraordinary efforts of volunteers and the money provided by sportsmen made the transplanting possible.  Nevada Bighorns Unlimited and the Fraternity of Desert Bighorns are to be commended for genuinely "putting their money where their mouth is."  They have provided money for habitat improvements and water developments for bighorn sheep and other wildlife through out Nevada.  Their water developments and their control of the spread of pinyon and juniper trees that crowd out plants needed for wildlife habitat have been very effective at many locations.

 

For some reason, both of these news articles included statements made by participants in the transplanting work that erroneously blame diseases from domestic sheep (ranchers) and hungry miners for causing there to be so few bighorn sheep in Nevada.   

 

Neither news article indicates the real problems that are known to result in bighorn sheep dieoffs including: malnutrition, disease pathogens and parasites endemic to bighorn herds, predators, bad weather, lack of water, and other sources of stress. When NDOW employees fail to identify and solve the real problems faced by bighorn sheep (or any species) they will fail to provide us with thriving bighorn herds well into the future.

 

This accusation of conflicts between bighorn sheep and domestic sheep has been around for some time, and has been used to justify agency regulatory decisions against domestic sheep grazing since the late 1970's.  Most biologists say they feel that epizootic (epidemic) outbreaks of pneumonia in bighorn sheep are caused by bacteria such as Pasteurella spp. or Mannheimia spp., which are somehow transferred from domestic sheep to wild sheep.  Pneumonia does occur, with similar symptoms in both domestic sheep and bighorn sheep, but there is no supporting scientific evidence that bighorn die-offs occur because of domestic sheep contact in the wild. Recent scientific research also indicates that Mycoplasma spp. may be present in sick bighorns.  It is very disturbing that after more than 30 years there is no scientific proof of this alleged disease transmission, and yet it continues to be stated as a fact by agency biologists. 

 

Please also note that the early explorers had to eat their horses and mules because they couldn't find game to shoot.  However, the Las Vegas article reports tens of thousands of bighorns flourishing in what is now Nevada in the 1860's, but does not document the source of that statistic.  Both articles claim that there were vast bighorn herds until the arrival of miners and ranchers from the United States.  If the bighorn herds actually existed, it would have been noted in the journals of early explorers because they would have celebrated finding an abundant source of meat for their camps.  The same article claims that early miners were able to cause significant bighorn die-offs by draining water supplies, and again there is no historic documentation to support that accusation.

 

MY REQUEST

Please develop a new bighorn sheep management policy to the effect that there is no measurable risk of pneumonia (Pasteurellosis) as a result of contact between domestic sheep and bighorn sheep.  You should recommend measures that will minimize contact between the species but there is no reason to absolutely prevent all contact.  Please direct the NDOW employees to immediately stop saying that domestic sheep diseases cause die-offs in bighorn sheep.  Please direct NDOW employees to provide this revised bighorn sheep policy to the various federal agencies, and further direct your employees to explain to the non-government organization volunteers and members what the new management criteria will be.  Those old accusations have been a huge cost to Nevada Sportsmen and ranchers, and the money and time spent blaming domestic sheep does not result in more bighorn sheep.

 

DISCUSSION OF POINTS WITHIN THE NEWS ARTICLES

In the Mount Grant story, it seemed odd to the point of irrational to state that this transplanting effort is planned to increase the number of bighorn living at high elevations when the transplanting is being done in the winter.  During the winter the bighorns have to move to the low elevations to escape the deep snows; yet they are placing these new bighorns on a mountain just in time for snow to either kill them or drive them to low elevations.  As animals that are new to the area they won't know where to move to, so if they find suitable winter range it will be by accident.

 

There was no mention of the severity of past mountain lion predation of bighorns on Mount Grant.  Unless NDOW has finally killed some mountain lions in that area, the lions will either eat the new bighorns very soon or if these animals are lucky they will move down near the highway and escape the predators just like the present herd of bighorns has done.

 

By the same token, the Delamar Range story did not mention how many bighorns are already present in that mountain range from earlier transplants and as a result of fairly intensive mountain lion controls.

 

Please note that both articles refer to very effective water developments that the biologists call "guzzlers", which catch rain and snow water and then stores the water in tanks  This is a form of construction that has been used for people and livestock for over 6,000 years.  More specifically known as water harvesting or water harvesting catchments, they are a standard feature of managed livestock grazing in many areas.  Here in Churchill County water harvesting for cattle is referred to as "water reapers".  This technique has long been successfully adapted for wildlife, for example my family constructed water guzzlers for quail and pheasants on our ranch in Oregon in the 1950's, many of which are still fully functional.   

 

Water guzzlers for bighorn sheep now provide water in mountainous areas where natural surface water does not exist, and bighorns transplanted to the water guzzler sites have survived pretty well for the most part.  One awful exception in recent years was the death of a large herd of bighorn sheep near Las Vegas due to the failure of NDOW to maintain a guzzler in good working order.  That location was one of many where there is no water for any animals to drink unless it is constructed --- improper maintenance of such guzzlers means that the bighorn sheep that were transplanted there (do not occur there naturally) will die of thirst.

 

Both articles imply that there were abundant wildlife populations in the Great Basin in the mid-1800's, and the wildlife died out when immigrants began mining and ranching in our area.  Please note that Nevada history shows that the early explorers in the Great Basin could not find game to eat.  Fremont, Ogden, King, Bidwell, and literally all of the others report the scarcity of game for sustenance.  Walker reports that his two trips into the Sierras involved severe hardship because of the lack of game in the Sierras.  There were a few locations with bighorn, deer, sagegrouse, or other food sources, but those were widely scattered and unpredictable.  In other words, what is now Nevada did not lose bighorn sheep herds to hunting in the 1800's, there were never any extensive herds to began with. 

 

Please remember that there were nearly 300 years of mining and ranching by people moving north from Mexico before the most recent immigration of people from the United States seeking gold and silver in the mid 1800's.  Native wildlife, including bighorn sheep, have had centuries to develop immunity to diseases of livestock and have presumably done so.  The establishment of ranching as we know it, beginning about 1860, resulted in habitat changes, predator controls, water developments, and other improvements that benefit wildlife to this day.  It can be shown that wildlife of all types, and especially bighorn sheep populations increased during the 1900's in the presence of ranching and livestock.  Records also indicate that bighorn sheep, deer, and the recently introduced elk all increase for periods of time and suffer catastrophic die-offs that are unrelated to livestock.  Some of the most obvious cause of die-offs is winter weather, over population of the most limited area of habitat, and predation.  Records show that the winter of 1889, followed by at least a half-dozen severe winters since 1900, resulted in the deaths of large herds of livestock and wild animals alike.

 

Both articles include a statement alleging disease transmission, such as the statement in the Mt Grant article apparently by the NBU representative: "Bighorn sheep populations in Nevada dwindled in the early 1900s due to overhunting and their susceptibility to diseases from domestic sheep."  In the Delamar Range article they quoted the Fraternity of Desert Bighorns representative as believing that: "The other reason [for bighorn dieoffs] was the vast array of ranchers that had domestic sheep.  There's no immune system in our wild sheep.  Many were lost by diseases from domestic sheep."  These statements are attributed to the bighorn organization representatives, but those people learned to say this, they didn't just make it up.  If NDOW disagreed with those statements then any one of the numerous NDOW employees who were present and supervising the transplanting efforts should have spoken up and corrected the NBU or FDB representatives.  It appears that the NDOW representatives passively allowed the accusation of disease transmission to show up in print once again.

 

Bighorn sheep diseases and parasites occur naturally in bighorn sheep; it is now well known that the various disease-causing organisms are endemic.   Often some unusual stress triggers disease, especially pneumonia, as found in events such as the recent die-off in Hayes Canyon in Washoe County and the die-off a couple of years ago in the Santa Rosa Range north of Winnemucca.  In each of these cases there was an immediate accusation that the cause was disease of domestic sheep, with no scientific proof.  Because they spend so much time condemning domestic livestock and the ranchers, our local biologists cannot identify the real problems.  Solving the real problems will result in more bighorn sheep.

 

There was no indication in either article that appropriate Veterinary precautions were applied to these two transplanting efforts.  Apparently NDOW did not complete assessments of the strains of particular disease organisms present in the isolated herds of bighorns prior to transplanting, or even quarantine the animals they caught.  It is obvious that their technique for determining if the various bighorn herds have established immunity to the pathogens they would encounter as a result of the transplanting, is simply a matter of mixing them together and waiting to see if any die. 

 

In the literature there is an obvious correlation of bighorn sheep dieoffs that occur after a transplanting effort.  There seems to be a huge risk of disease transmission from bighorn sheep to bighorn sheep as a result of transplanting bighorn sheep into an already occupied bighorn sheep habitat.   When bighorns or any wildlife is transplanted, all of the disease and parasite organisms that the animals carry are transplanted with them.  A Nevada example occurred in Elko County when NDOW tried to improve the genetic diversity of Rocky Mt Bighorn Sheep by transplanting bighorns from one herd and releasing them into another herd.  Following that transplanting effort, bighorns died of disease carried by the bighorns with no domestic sheep involvement.  Biologists fooling around with bighorn herds are one of the greatest dangers or threats to the health of bighorn sheep; nearly as dangerous as predators and winter-kills.

 

Stating or implying that disease from domestic sheep is the single most dangerous risk to bighorn sheep is purely conjecture.  This allegation is very pervasive, it appears in a number of NDOW publications and is frequently heard when biologists gather to discuss bighorn sheep.  It has been repeated so often by agency and university biologists that even the bighorn NGO's state that disease transmission is a fact.  However, Nevada Veterinarian, Dr. Rink, has studied the available scientific literature and recently wrote (April 2007) that there is no scientific proof that contact between domestic sheep and bighorn sheep in natural habitats has caused either death or sickness in bighorn sheep.  Dr. Marie Bulgin, Caine Veterinary Center in Idaho, went one step further by saying that the threat of disease transmission from domestic sheep is a myth.  Please see the detailed discussion below. 

Allegation of the threat of disease from domestic sheep

 

Following is material extracted from a letter sent by F.I.M. Corporation, a Lyon County Nevada sheep ranch to the U.S. Fish and Wildlife Service, May 15, 2007; regarding the 5 year status review of the Sierra Nevada Bighorn Sheep (SNBS).  F.I.M. Corporation has incorporated much of the current knowledge about disease in both domestic and bighorn sheep in these comments.

 

 

I agree with their conclusions and I couldn't have written them better myself.

 

I have inserted several comments in Italics where clarification was needed.  Please accept these paragraphs as if the statements addressed to FWS were addressed to NDOW since the statements are technically sound concerning Nevada bighorn sheep:

 

"Literature cited by the US FWS in support of the conclusion that diseases of domestic sheep cause catastrophic epidemics in bighorn sheep have now been shown to be reporting coincidental losses of bighorn populations, they provide circumstantial evidence at best.  Careful scientific study of disease in bighorn sheep and domestic sheep has it's beginning in the 1990's, including genetic analysis of the pathogens isolated from the animals.  In the words of Dr. Rink (July 2007): "To date not a single report has been published where disease transmission from DS to BHS was proven to be the cause for morbidity and mortality in BHS in their natural habitat."

 

Deficiencies of the literature chosen [by Biologists] to illustrate a threat of disease transmission were explained by Tom McDonnell in the paper submitted to the USFWS during the Listing comment period entitled "Bighorn Sheep and Domestic Livestock Conflict"  (March 16, 2000).  Dr. Anette Rink, State Veterinary Laboratory Supervisor, Nevada Dept. of Agriculture, provided an additional critique of the scientific literature in "Review of published and current research and proposal for future research to assess the role of domestic sheep/bighorn sheep contact in bighorn sheep die-offs." (June 10, 2004).  Dr. Rink presented this document to Bob Vaught, Forest Supervisor, Humboldt-Toiyabe National Forest and a fairly large group of participants on June 10,2004.  She was joined by Dr. David Thawley (UNR), Dr. Hudson Glimp (UNR), and Dr. David Thane (Nevada State Veterinarian) in a discussion of pathogens, hosts, disease and disease transmission.  Dr. Rink's presentation was described as compelling testimony by a credible scientist in the Forest Service account of this meeting.  As a result, the Forest Service (Mr. Vaught), University of Nevada Reno, and F.I.M. jointly sponsored a seminar, the "SNBS Technical and Scientific Roundtable Discussion" held in Reno in February 2005.  This information, including the transcription of presentations at the Scientific Roundtable have been provided to the FWS in previous correspondence.  [Please note that NDOW was a participant in this 2005 seminar]

 

In 2005, the Payette National Forest completed a "Risk Analysis" concerning contact of bighorn sheep in the Idaho portions of Hell's Canyon with domestic sheep.  Written comments concerning this risk analysis were submitted by Dr. Marie Bulgin,  Dr. Al Ward, and Dr. Glen Weiser all Veterinarians with the Caine Veterinary Research Lab, and include the following, all of which have previously been provided to the FWS:

        1.   Bulgin, Marie S., July 2006, letter to Pattie Soucek, Forest Planner, Payette National Forest,  Re:  Comment Concerning the Risk Analysis of Disease Transmission Between Domestic Sheep and Bighorn Sheep on the Payette National Forest (2006). (7 pp.)

  1. Rink, Anette., July 2006, letter to Pattie Soucek , Payette NF,                   re: Comments on the ‘Risk Analysis of Disease Transmission between Domestic Sheep and Bighorn Sheep on the Payette National Forest, 2006' (3 pp.)

  2. Ward, Alton C.S. and Glen C. Weiser. July 2006.  A Bibliography labeled "PUBLICATIONS AND PRESENTATIONS (past 16 years) REGARDING ORGANISMS ASSOCIATED WITH RESPIRATORY DISEASE IN BIGHORN SHEEP." (4 pp.)

  3. Ward, Alton C. S., July 14, 2006, letter to Ms. Pattie Soucek, Payette NF

re: Risk Analysis of Disease Transmission Between Domestic Sheep and Bighorn Sheep on the Payette National Forest, February 6, 2006 (8 pp.)

  1. Weiser, Glen C., July 12, 2006, letter to Pattie Soucek, Payette NF   

re: Risk Analysis of Disease Transmission Between Domestic Sheep and Bighorn Sheep on the Payette National Forest (2006). (6 pp.)

  1. Weiser, Glenn C.  July 18, 2006.  Letter to Pattie Soucek , Payette NF.  

re: Risk analysis of  disease transmission between domestic sheep and bighorn sheep on the Payette National Forest (February 2006); Critique of Forest Service (Schommer and Woolever, 2001) use of a Summary Judgment by Judge Ashmanskas as a scientific reference (2 pp.)

 

Disease transmission referred to in the FWS Listing requires the transfer of pathogens (Pasteurella sp.) from the respiratory tract of one animal into the respiratory tract of another through direct contact such as licking or within aerosols when a sick animal coughs.  The bacteria are very short lived outside of the host animal.  In an effort to help people better understand the nature of respiratory disease caused by Pasteurella spp., Dr. Nancy East  and Dr. Don Knowles have both provided some technical background this past winter.  Both are highly qualified Veterinarians. 

 

Dr. Nancy East confirmed that it is nearly impossible for Pasteurella to be passed between domestic sheep and bighorn sheep in the wild.  Dr. East explained to the SNBS Stakeholder subcommittee meeting held on January 16, 2007, that detailed knowledge of sheep behavior indicates that neither wild sheep nor domestic sheep will tolerate other sheep in close proximity to their faces.  That is due to the trait of "facial recognition" exhibited by sheep.  Since the most effective mode of transmission of Pasteurella is by direct exchange of mucous from the nose or saliva, the innate avoidance of facial contact means that the primary opportunity for Pasteurella transmission does not exist in unconfined sheep in the wild.  Dr. East referred the committee to a book entitled "The Behaviour of Sheep, Biological Principles and Implications for Production", J.J. Lynch, 1992.  These same authors provide clear illustration of the likelihood of various sheep breeds to travel independently of their herds or otherwise stray.  Their data illustrate the fact that Merino breeds of sheep, such as FIM's are very gregarious and this feature makes the management of herding on open range not only possible but successful.

 

Dr. Don Knowles (personal communication on January 22, 2007) explained that from the standpoint of epidemiology, an outbreak of disease is controlled by the conditions required for the "disease threshold".   Dr. Knowles is the Research Leader, USDA Agricultural Research Service, Animal Disease Research Unit located at Washington State University and University of Idaho.  A number of conditions must be met before a given pathogen can cause disease, consequently when one or more of the conditions are eliminated then the pathogens become less and less able or likely to initiate disease.  These conditions include such features as: (1) the amount of pathogen (dose); (2) virulence of the pathogen; (3) amount of contact; (4) genetic background of new host (innate resistance or immunity); (5) behaviour of hosts; (6) nutritional status; (7) parasite loads; and (8) various other sources of stress. 

 

Dr. Knowles explained that the agencies need to show that the threshold conditions found under experimental conditions where disease occurred also occur in nature before they can honestly use the results of laboratory experiments to predict disease in nature.  In scientific studies, the scientist is expected to first, factually describe what a given experiment shows and second, factually state what an experiment does not show.  Much of the literature cited by biologists to conclude that disease transmission occurs in nature are in a third category of projecting things in wild populations that were not measured in the experimental design."

 

 

 

CONCLUSION

The effects of this conjecture about disease transmission include a great deal of time and money spent by government agencies attempting to stop a threat that doesn't exist; a huge cost in money, time, and lost productivity to sheep producers throughout the Nevada; and no increase in bighorn sheep populations as a direct result from regulations based on the alleged threat of disease.

 

Biologists are pulling the wool over our eyes with regard to dangers of domestic sheep to bighorn sheep.  Their allegation of a threat of disease transmission from domestic sheep is a myth not a fact.

 

 

Sincerely,

 

 

 

 

Floyd Rathbun

PO Box 1612

Fallon, NV 89407

(775)423-4267

This e-mail address is being protected from spambots. You need JavaScript enabled to view it

 

 

 

 

 

 

 

 

 

Floyd Rathbun's education includes college degrees in Range Management and in Wildlife Biology and additional education and training throughout his professional career.  Positions held during the past 40 years include employment as a Wildlife Biologist by Oregon Fish and Game, employment in Nevada as a Range Conservationist by both the Bureau of Land Management and the Soil Conservation Service, employment as a Soil Conservationist by the Soil Conservation Service, and employment as a Wildlife Biologist by the Department of Defense (NAS Fallon).  Floyd's education and experience has provided highly technical knowledge and skills concerning the ecology of rangelands and the attributes of wildlife habitats as well as a more generalized knowledge of nutrition and diseases of ruminant animals in Nevada.  Floyd is currently self-employed as a Certified Range Management Consultant. 

 

 

LIST OF ATTACHMENTS

1.     Bulgin, Marie S., July 2006, letter to Pattie Soucek, Forest Planner, Payette National Forest,  Re:  Comment Concerning the Risk Analysis of Disease Transmission Between Domestic Sheep and Bighorn Sheep on the Payette National Forest (2006). (7 pp.)

2.     F.I.M. Corporation, May 15, 2007, letter to the Field Supervisor, U.S. Fish and Wildlife Service, Ventura Fish and Wildlife Office  re: Five year status review of the Sierra Nevada bighorn sheep endangered Distinct Population Segment.(12 pp)

3.     Knowles, Don and Anette Rink. September 27, 2006. Outline of Concerns relating to the perception of disease transmission issues at the Livestock/Wildlife interface in the Western United States. (5 pp)

4.     Rink, Anette., July 2006, letter to Pattie Soucek , Payette NF,   re: Comments on the ‘Risk Analysis of Disease Transmission between Domestic Sheep and Bighorn Sheep on the Payette National Forest, 2006' (3 pp.)

5.      Ward, Alton C. S., July 14, 2006, letter to Ms. Pattie Soucek, Payette NF  re: Risk Analysis of Disease Transmission Between Domestic Sheep and Bighorn Sheep on the Payette National Forest, February 6, 2006 (8 pp.)

6.      Weiser, Glen C., July 12, 2006, letter to Pattie Soucek, Payette NF    re: Risk Analysis of Disease Transmission Between Domestic Sheep and Bighorn Sheep on the Payette National Forest (2006). (6 pp.)

7.      Weiser, Glenn C. July 18, 2006.  Letter to Pattie Soucek, Payette NF.   re: Risk analysis of  disease transmission between domestic sheep and bighorn sheep on the Payette National Forest (February 2006); Critique of Forest Service document (Schommer and Woolever, 2001) including use of a Summary Judgment by Judge Ashmanskas as a scientific reference (2 pp.)

 

Last modified on Thursday, 14 February 2008 15:03
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