Fraudulent figures, sterilization and underpopulation

PM Burros Wild 2 © Carl Mrozek

To:  Heather van Blokland at KJZZ

Rio Salado College and Maricopa Community College, Arizona

I am emailing you directly because comments cannot be posted to your article.

First, let me commend you for correctly identifying PZP as a “sterilization drug.” The Bureau of Land Management (BoLM) and the Humane Society of the United States (HSUS) both like to refer to it as “birth control,” but PZP is actually a sterilant.  More on that later.  The reason for my email is to alert you that BoLM has given you false information regarding the wild horses and burros.

While a reporter or any member of the public should be able to secure accurate data from government agencies, BoLM’s data is fraudulent as concerns wild horses and burros.  BoLM is aggressively pursuing a disinformation campaign against the mustangs, concocting a crisis that does not exist, and using scare-tactics to secure increased funding for itself.  Let me now address certain points cited in your article.

Herd-growth rates:  Equids are slow-growth species when it comes to reproduction. The gestation period for horses lasts 11 months, and a mare produces just 1 foal.  The gestation period for burros lasts 12 to 14 months, and a jenny is less fertile than a mare.  While an independent study of BoLM’s records did confirm an almost 20% birth rate for wild-horse herds, and an almost 15% birth rate for wild-burro herds, the study also found that 50% of foals perish before their first birthday.  Thus, the effective increase in population from new foals is just 10% for wild horses and 7% for wild burros.  Adult mustangs also die.  They succumb to illness, injury, and predation at a rate of at least 5% a year. So, what is a normal herd-growth rate?  Around5% for wild horses and about 2% for wild burros, probably less in each case.  Thus, a herd could not double every four years — that’s just BoLM propaganda.

Fraudulent figures:  There is no overpopulation except on BoLM’s falsified spreadsheets.  Reviews of the agency’s population-estimates reveal biologically-impossible herd-growth rates.  For instance, in Arizona, BoLM reported that the Big Sandy herd grew from 250 burros to 754 burros in one year, a 202% increase.  In Nevada, BoLM would have us believe that the Lava Beds herd grew from 40 burros to 350 burros in one year, a 775% increase.  In Wyoming, BoLM declared that the Salt Wells Creek herd grew from 29 horses to 616 horses in 6 months (yes, months), a 2,024% increase.  The agency’s “data” is chock-full of such preposterous growth-estimates.  So, when you hear talk of how the wild horses are reproducing “exponentially,” that’s a sure sign that the numbers have been falsified.

Wild horses and burros are underpopulated:  Per the guidelines of BoLM’s own geneticist, 83% of the wild-horse herds and 90% of the wild-burro herds suffer from arbitrary management levels (AMLs) set below minimum-viable population (MVP).  Low AMLs enable BoLM to claim an “excess” in herds whose numbers, even if they were over AML, would still not reach MVP.  For instance, the AML for Arizona’s Black Mountain herd was set at 382 to 478 wild burros.  The Black Mountain Herd Management Area comprises 925,425 acres, or 1,446 square miles.  Thus, per the AML, BoLM implies that each burro needs 1,936 to 2,423 acres, or about 3 to 4 square miles per burro.  If BoLM projects there to be 2 burros per 3 square miles, the agency declares an “overpopulation” because there is “double the number” that the AML allows.  As you can see, being “over AML” is meaningless as well as misleading.  But the low AMLs, combined with falsified, biologically-impossible herd-growth estimates, give BoLM an excuse to scapegoat those few wild horses and burros for the range-damage done by the millions of livestock that overgraze the public lands.

Adoptions:  Have not declined — let alone “disappeared” — contrary to what BoLM led you to believe.  It’s just that BoLM used to count the thousands of sales-for-slaughter as “adoptions.”  Now that only true adoptions — “forever-family” placements — qualify, it just seems as if the number has declined.  However, wild horses are not homeless horses.  They have a home — where they belong — on the range.

HSUS:  Is the registrant of PZP / ZonaStat-H with the Environmental Protection Agency.  Thus, HSUS’ information is not impartial because the organization has its reputation to protect.  Further, HSUS has submitted a proposal for a multi-year project in which BoLM would pay for HSUS staff to experiment on Arizona’s burros via “opportunistic” darting with PZP.

Pesticide:  PZP is not just a sterilant but also a registered pesticide that was approved by the EPA for use on wild horses and burros “where they have become a nuisance.”   However, PZP was registered without the standard testing requirements.  There is currently a lawsuit challenging the legitimacy of the registration, especially in light of new studies that have disclosed PZP’s many adverse side-effects.

Sterilizing mustangs:  PZP is a potent weapon in BoLM’s arsenal — for its biological warfare against the wild horses.  But population control for wild horses is unnecessary because there is no overpopulation.  Why would we contracept herds whose population is inadequate for genetic viability?  Why would we contracept herds based on falsified figures?  Logically we wouldn’t and ethically we shouldn’t.  Further, if PZP were going to stop the roundups, it would have done so long ago for the famous Pryor Mountain herd, home to Cloud, the stallion who was the subject of a number of documentaries that aired on PBS.  The Pryor Mountain mares have been darted with PZP for nearly two decades.  Yet roundups have been scheduled there like clockwork every 3 years and, in spite of intensifying the PZP treatments recently, BoLM tried to implement yearly roundups until stopped by a Friends of Animals lawsuit.

PZP — the anti-vaccine:  PZP causes disease — auto-immune disease.  PZP “works” by tricking the immune system into producing antibodies that target and attack the ovaries.  The antibodies cause ovarian dystrophy, oophoritis (inflammation of the ovaries), ovarian cysts, destruction of oocytes in growing follicles, and depletion of resting follicles.  The mare’s estrogen-levels drop markedly as PZP destroys her ovaries.  Ultimately, PZP sterilizes her.  Because PZP stimulates the immune system, it ironically works “best” — sterilizes faster — in mares that have strong immune-function.  Such mares respond to the anti-vaccine and produce quantities of PZP antibodies that destroy their ovaries.  But, conversely, PZP may not work at all in mares whose immune-function is weak or depressed.  Those mares fail to respond to PZP.  They keep getting pregnant and producing foals who, like their dams, suffer from weak immune-function.  So, the PZP pesticide works against the very horses that Nature has best equipped for survival-against-disease while favoring and selecting for the immuno-compromised.  Worse yet, radioimmunoassay tests indicated that PZP antibodies are transferred from mother to female offspring via the placenta and milk.

Health-risks to volunteers:  As for the well-meaning volunteers who dart wild horses, EPA’s Pesticide Fact Sheet for PZP advises that Personal Protective Equipment requirements include long sleeved shirt and long pants, gloves and shoes plus socks to mitigate occupational exposure.  EPA specifically warns that pregnant women must not be involved in handling or injecting ZonaStat-H, and that all women should be aware that accidental self-injection may cause infertility.  Unfortunately, PZP’s manufacturer misrepresented PZP as “so safe it is boring.”   But research shows that PZP is a powerful hormone disruptor.  Further, consider the magnitude of the risk — the PZP-in-question is a horse-sized dose.  If volunteers think PZP is safe, they will be less likely to protect themselves from this dangerous pesticide.

Mengelian experiments:  The Big Lie of “overpopulation” is the pretext for BoLM’s war against the wild horses, and the wild horses are prisoners of that war.  It’s BoLM’s version of the “Shock Doctrine,” wherein the agency concocted a phony crisis to push through policies antithetical to the Wild Horse Act against the will of The People.  Now, BoLM is funding surgical-sterilization studies on the equine POWs to develop a Final Solution to the “problem” — handing out $11 million for these diabolical experiments.  The grant money is surely intended to buy loyalty and silence potential criticism from academia.  Plus, BoLM, a corrupt, rogue agency, gets to cloak itself in respectability by affiliating with prestigious universities.

Should you wish to learn more about how BoLM is mismanaging Arizona’s wild burros, I would be happy to send you a copy of comments recently submitted.  Just let me know.


Marybeth Devlin

Miami, FL

Protect Mustangs is a 501c3 nonprofit organization who protects and preserves native and wild horses.

Conversation about fertility control with Brett Hass, retired biologist previously with NSA (part 1)

Don’t let pesticides like Gonacon™, PZP or SpayVac® manage native wild horses to extinction. The Spin Dr.’s and some ignorant horse advocates are pushing fertility control on underpopulated wild horses. Know the truth and expose those spewing the spin.

PM Gonacon Pesticide Fact Sheet

Read the entire Gonacon™ Pesticide Fact Sheet


John Cox: Brett, you’re a retired biologist, previously with the NSA for how many years?

Brett Hass: 46 long years John. We met in Vietnam, when we a lot younger my friend (smiles). We were doing wildlife and vegetation studies in your AO (area of operations). That was my first assignment with the NSA, as a matter of fact.

John Cox: Let’s cut through all of that. What do you think of Gonacon™ and some of the other fertility controls BLM is using?

Brett Hass: As usual, and as government agencies do and BLM and DOI are extremely guilty, they pretend that science guides its wild horse and burro management strategies. So the agencies involved go forth and resolve issues, supposedly, with experimental drugs–in this case GonaCon™. The question is, in reality, does it resolve anything at all, or is it simply to further experimentations with this drug and the wild horses the most expendable of situations currently?

The problem is very obvious, with the first-time use of an experimental drug, they act like children with a new toy–but this toy is extremely dangerous, to not only the horses and actually lead them to extinction, but the environmental consequences are apparently neglected entirely? (shakes his head negatively). . .

But let’s get real, the very absence of science contradicts any time of sound reasoning for its use whatsoever. So once again we have a government agency, using a Nazi-Type experimental fertility drug on horses and other wildlife–without knowing, or even acknowledging for that matter, what the long-term consequences are–or in perception–the problems that will arise in its actual use.

There is no resolution, as I reviewed the population situation and see first hand there is no over-population if wild horses just within the BLM numbers alone; but livestock, that is a completely different matter, in reality.

John Cox: In your appraisal of the information you’ve read, would you, as a tenured Wildlife Biologist for over 50 years, use this drug?

Brett Hass: Absolutely not! There is no pertinent reasoning to use it right now and especially on wild horses or much of anything else for that matter. Our wildlife and environment is simply too important to be so frivolous with such activity, especially an unknown situation, as fertility drugs used in our natural environment. But as you say, ignorance is quite something, and our government seems to portray ignorance quite well, and frankly the only situation they seem to be competent to accomplish.

Much more on this discussion with Brett Hass later . . .


Below is the original PZP Pesticide Fact Sheet before HSUS seems to have lobbied the EPA to make changes to the chemical class. It’s still only approved as a pesticide to manage pests. PZP is made from slaughterhouse pig ovaries mixed with modified freund’s complete adjuvant.

PM PZP Test mares

(American wild horses used in fertility control experiments)

© John Cox, printed with permission

John Cox is a Vietnam Vet, living in the mountains of the Pacific Northwest who writes about the environment. He’s passionate about saving America’s wild horse herds and wolves. 

Read John Cox’s blog at:

Have you read about the Gonacon™ Experiment on the Water Canyon herd and the UNLUCKY 11 orphans? It all started as a PZP proposal and went down the slippery slope. . .  Read about it here:

PZP Pushers are misleading the public as there is no evidence of overpopulation

PM PZP Auto-immune disease

PZP = Slow Extinction

While touted as a “vaccine,” porcine zona pellucida — PZP — is actually a perversion of a vaccine — an anti-vaccine — whose mode-of-action is to cause auto-immune disease. PZP tricks the immune system into producing antibodies that attack the ovaries, inducing ovarian dystrophy, oophoritis (inflammation of the ovaries), and ovarian cysts. Worse yet, per radioimmunoassay, the PZP antibodies are transferred from mother to young via the placenta and milk. The antibodies cross-react with and bind to the zonae pellucidae of female offspring. Although hyped as a “non-hormonal” method of birth-control, PZP causes estrogen-levels to plummet as the ovaries degenerate. Despite the manufacturer’s claim that PZP is “reversible,” its effects wear off unpredictably. In herds under PZP “management,” the birthing season extends to nearly year-round, putting the life of the foals and mares at risk. Because PZP messes with the immune system, it “works” best on the healthiest fillies and mares — those with strong immunity — ironically, rendering them sterile even with just a few treatments. Filles injected with PZP before they have reached puberty are particularly vulnerable to immediate sterilization. Conversely, PZP has little-to-no effect on fillies and mares with a weak immune system — they continue to become pregnant. Thus, a herd being treated with PZP is undergoing selective breeding for low immunity, which puts the population at risk for disease — and ultimately, extinction. ~Marybeth Devlin, member of The Facebook Forum on PZP for Wild Horses and Burros.

PZP = Slow Extinction

No excess wild horses in the Pryors

PM PZP Betrayal


PZP is a risky pesticide. Will it ruin the treasured herd?

By Marybeth Devlin

The issue underpinning the use of PZP and the continuing cycle of removals of wild horses from the Pryor Mountain Wild Horse Range is: Whether there are excess wild horses. No, there aren’t. BLM creates the illusion of an overpopulation by administratively setting the maximum herd-size below minimum-viable population. The International Union for the Conservation of Nature determined that, if a herd were managed carefully per a stud-book, it could sustain itself genetically at a minimum of 500 individuals. Compare that number to BLM’s maximum: 120.

In fact, according to the latest genetic analysis, the Pryor Mountain herd is evidencing “a general trend for a decline in variations levels of the herd.” The recommendation was to “increase population size.” Yet, BLM stubbornly insists on its own failed approach of artificially limiting herd-size, declaring that it disagrees with the scientific “interpretation.”

But can the range accommodate more horses? Yes. By way of comparison, BLM allots 38 acres per cow or calf when setting the stocking-rate for livestock grazing. Thus, the 33,187 acres that compose the Pryor Mountain habitat can support 500 to 873 horses. When the WHR is restored to its original configuration, 44,920 acres, the high-bound can be increased to 1,182.

As for PZP, numerous independent studies have disproved the old theory that PZP merely blocks sperm attachment. In fact, PZP’s mechanism of action is to alter ovarian function, causing inflammation of the ovaries and cyst formation. PZP provokes an auto-immune response, wherein the pig-ovary-derived PZP antibodies attack the mares’ ovaries, resulting in dystrophy of those reproductive organs. Despite being hyped as a non-hormonal contraceptive, PZP causes “markedly depressed oestrogen secretion” in mares treated for just three consecutive years. The latter finding was disclosed by Dr. Kirkpatrick himself 23 years ago. PZP-use is associated with stillbirths, altered ovarian structure and cyclicity, interference with normal ovarian function, permanent ovarian damage, prolonged breeding season, and unusually-late birthing dates. A particularly troubling finding suggests that PZP can be selective against a certain genotype in a population.

PZP is touted as reversible; however, a recent study warned that just three years of treatment, or administration of the first PZP injection before puberty, may trigger infertility in some mares. Thus, only two PZP injections could be viewed as relatively safe, but it appears that even one injection is risky. The researchers warned that inducing sterility may have unintended consequences on population dynamics by, ironically, increasing longevity while eliminating the mares’ ability to contribute genetically.

Most pertinent to the Pryor Mountain herd is a longitudinal study on three herds treated with PZP — Little Book Cliffs, McCullough Peaks, and … Pryor Mountain. The researchers found that the birthing season lasted nearly year-round: 341 days. Out-of-season births put the life of the foals and the mares at risk. That same longitudinal study found that, following suspension of PZP injections, there was a delay in the mares’ recovery of fertility that lasted 411.3 days (1.13 years) per each year of PZP treatment. Thus, mares injected for four consecutive years (per BLM’s “prescription”) would be expected to take 1,645.2 days (4.51 years) to regain reproductive capacity. If disaster were to befall the Pryor Mountain horses, even if PZP were stopped immediately, it would take years for the herd to recover, if ever.

PZP has neither stopped nor slowed the roundups. Only lack of holding space has done that. Even the Pryor Mountain herd, injected for decades with PZP, is facing removals again this summer (per the usual three-year cycle) in addition to an intensified PZP “prescription” to be administered per an “equal opportunity program” eerily similar to Communist-China’s one-child policy. What’s ironic is that, for all the interference, BLM has achieved basically the same — or worse — record as has been attained the International Society for the Protection of Mustangs and Burros. ISPMB complies with the “hands-off” minimum-feasible management approach stipulated by the Wild and Free-Roaming Horses and Burros Act. ISPMB’s two wild herds grew 8.73 and 5.08 percent, respectively, without PZP and without removals. Pryor Mountain’s most recent report — reflecting management with PZP and with removals — grew by 8.26 percent.

BLM needs to get out of the way of Nature. Let the Pryor Mountain herd find its own appropriate population level.

(Note: Beware of petitions pushing PZP. Be sure to read everything you sign these days especially the fine print!)

Please donate to Protect Mustangs’ Legal Fund: to help the voiceless in court. Thank you!

Is PZP causing young fillies to be raped by mobs of studs?


By U.S. Government [Public domain], via Wikimedia Commons

By U.S. Government [Public domain], via Wikimedia Commons

Anne-Marie Pinter writes in the Forum on PZP, “Encore the yearling filly stolen by a band of bachelors and held hostage by a BAND of mature bachelor’s, that filly is too small to fight off an adult stallion let alone a band who will rape her whether she is heat or not because she cannot fight them off,and cannot outrun them- so not to worry if she lives thru it -she will be sterile as the cervix will be so badly torn it will never form a seal..Is it because of PZP-well go to BLM’s website and read under the fertility program management where they acknowledge since the use of PZP it has been “noted” stallions have started breeding yearlings and mares are foaling as 2-year-olds. underdeveloped and not mature enough to know how to be a good mother..this is NOT behavior ever noted by Ginger before the use of PZP..hope all you sleep well tonight, and realize-there are consequences to the use of PZP..this is one among many.”

JOIN the Forum on PZP to learn the TRUTH about PZP (Native, 22, etc.) Once informed people can’t support PZP and that’s why the PZP Pushers are trying to hide the information.

Ecologist Craig Downer speaks out against using PZP in the Pryors

Craig Downer

Craig Downer (Photo © Cat Kindsfather, all rights reserved.)

Protect Mustangs’ Advisory Board member offers holistic management based on Reserve Design as opposed immunocontraceptives approved by the EPA as pesticides 

April 15, 2013

Mr. James M Sparks, Billings Field Manager
BLM, Billings Field Office
5001 Southgate Drive
Billings, MT 59101-4669
Re: 4700 (MT010.JB): Scoping Notice for Increased Use of Fertility Control on Wild Horses within the Pryor Mountain Wild Horse Range

Dear Mr. Sparks and To Whom It May Concern:

Montana BLM has zeroed out six of its seven original wild horse Herd Areas. The only one that still has any wild horses left is the Pryor Mountain Wild Horse Refuge, which was established prior to the 1971 Wild Free-Roaming Horses and Burros Act (WFHBA). In fact, Montana BLM has decided to zero out 82% of the original legal acreages that should have been set aside “principally” for the wild horses in the wild. This is a greater percentage of zeroing out than any other Western state. New Mexico comes closest at 77%. Given this initial injustice, it would seem that in the remaining area still home to wild horses, they would be treated much more fairly and given the resources and the Appropriate Management Levels (AML) that would assure their long-term viability. But such has clearly not been the case in the Pryors, where the AML range of 90 to 120 falls far short of the 250 individuals that is recommended for long-term viability in the wild by the IUCN SSC Equid Specialist Group (1992).

So I take this opportunity to thank you for sending me this scoping notice. I have reviewed this and wish to oppose the intensified use of PZP on the Pryor Mountain wild horses. They have been assigned an AML that is non-viable; and the further tampering with and inhibition of their reproduction would make them even more non-viable, especially in view of their long-term future survival, as well as their ecological adaptation to the Pryor Mountain ecosystem.

As a wildlife ecologist who appreciates these animals for the returned North American natives they are, I am particularly concerned that BLM’s repeated semi-sterilization of mares (often resulting in permanent sterilization of the mares) will cause serious social disruption. The logic is this: those mares who fail to achieve pregnancy quickly become disaffected with their band stallions and go off with other stallions in their futile attempts to achieve pregnancy. Similarly the stallions become desperate in their repeated futile attempts to impregnate the mares. This leads to widespread discontent and disruption, both within and between the wild horse bands composing the Pryor Mountain – as any – herd. This results in the serious neglect by adults of their duties to educate the younger members of their bands who are not as inhibited in their breeding as before. These immature individuals attempt to breed prematurely when the social units are in disarray. If intact they would be learning the very important lessons for survival in the demanding Pryor Mountain ecosystem, with its harsh winters, etc. As the effect of PZP wanes and some mares come back into a fertile condition, many give birth out of the normal Spring and early Summer birthing season, even in the late Fall or Winter when cold and storms cause them to greatly suffer and even die, along with their offspring. This is totally opposite the true intent of the WFHBA!

The intensified PZP approach to reducing reproduction in the Pryor Mountain wild horse herd is not the correct policy to adopt. It does not adhere to the core intent of the WFHBA. It is a major step toward domesticating these wild horses and seriously compromises their true wildness and natural adaptiveness. What I am offering in place of this “quick fix drug” approach to preserving, protecting, and managing this cherished herd (and all herds should be cherished) is a major and widely employed branch of the science of wildlife conservation known as Reserve Design. If properly and conscientiously applied, this would: (a) obviate the need to drug the Pryor Mountain mustangs by creating a naturally self-stabilizing horse population that would truly become “an integral part of the natural system of public lands” (preamble of WFHBA); and (b) “achieve and maintain a thriving natural ecological balance on the public lands” and “at the minimum feasible level” of interference by man. Both of these mandates come directly from Section 3 a of the WFHBA and should be adhered to by authorities of the BLM and USFS, the two agencies charged with fulfilling the act.

To accomplish these goals, you should:
(1) Incorporate the Pryor Mountain’s natural barriers such as the steep cliffs along the eastern side of the refuge that lead down to the Bighorn River. These will limit the expansion of the herd. Where necessary they could be complemented by artificial semi-permeable barriers.

(2) Restore natural horse predators such as the puma and wolf whose effect upon the wild horses would accord with natural selection and produce a more fit and well-adapted population in the Pryor Mountains. It has been a mistake to have puma hunting season reopened in the Pryors, and this should be rescinded in collaboration with Montana’s wildlife department.

(3) Avail yourself of options provided by Section 4 and 6 of the WFHAB in order to secure truly long-term-viable habitat for a truly long-term-viable wild horse population that is not subject to inbreeding and decline. Section 4 allows private landowners whose properties lie adjacent to the Pryor Mountain wild horse refuge to maintain wild, free-roaming horses on their private lands or on land leased from the government provided they protect them from harassment and have not willfully removed or enticed them from public lands. This is an outstanding opportunity for the public to help in preserving and protecting the wild horse herds at healthy population levels, i.e. to complement federal Herd Areas (BLM) and Territories (USFS). Section 6 of the WFHBA authorizes cooperative agreement with landowners and state and local governments to better accomplish the goals of the WFHBA. This allows for providing complete and unimpeded habitat for long-term viable wild horse populations. BLM should invoke Section 6 to establish cooperative agreements with both the National Parks Service (USDI, same as BLM) re: McCullough Peak national monument (which I believe already has such an agreement) and Bighorn Canyon National Recreation Area, as well as the Custer National Forest (USDA) in order to expand available habitat for the Pryor mustangs. As concerns the Custer National Forest, the USFS officials should not be allowed to get away with the fence they have erected and that restricts the wild horses’ traditional access to summer grazing meadows. This is on the west side of East Pryor Mountain and consists of a two-mile long buck and pole fence. This area was occupied by the wild horses in 1971 and should be a recognized legal area for them, as was documented by Dr. Ron Hall who did his study of the Pryor Mountain wild horses. It is also a prime public viewing area with great scenic visits, as I recall from my visit there in June of 2003. By erecting this fence, Custer National Forest officials defied their mandate to protect and preserve wild horses under the WFHAB; this is subject of an ongoing legal suit. BLM officials must insist this fence be taken down!

(4) Once a complete viable habitat is secured with adequate forage, water, minerals, shelter, wintering and summering habitat components, etc., the Pryor Mountain wild horses should be allowed to fill their ecological niche here and to naturally self-stabilize. This they will do as ecological climax species, as species belonging to the mature ecological sere, if only given the time and the space and the requisite non-interference by man. Thus, the socially and ecologically disruptive roundups will come to a halt; and the wild horses will harmonize with all the unique and fascinating animal and plant community that is found here. Given the opportunity, the wild horses will enhance the Pryor Mountain ecosystem and people will come to appreciate the virtue of a wild-horse-containing ecosystem.
(5) Semi-permeable fences could be constructed along the refuge’s peripheries but only where necessary. Buffer zones around the Pryor Mountain wild horse refuge should be established in order to contain the wild horses and keep them out of harm’s way. Within this buffer zone, mild forms of adverse conditioning techniques could be employed to keep the horses within their refuge. Win-win cooperative agreements with local people whereby they benefit from the wild horses as through giving paid eco-tours, providing lodging and meals, participating in monitoring and protection of the horses, etc., should be stressed. These positive opportunities should be expanded in order to make Reserve Design a success.

I go into greater detail as to how Reserve Design can be successfully applied in my recently published book: The Wild Horse Conspiracy, where I also describe the Pryor Mountain situation. I hope that you can get a copy and read it with an open mind. Look under Reserve Design in the Index. Let me know if you want a copy.

Hoping you will give serious consideration to the points here raised. Anxiously awaiting your response.

Craig Downer

Craig C. Downer
P.O. Box 456
Minden, NV 89423

Craig C. Downer is a wildlife ecologist (UCalifBerk, UNevReno, UKanLawr, UDurhamUK) who has extensively studies both the wild horses of the West and the endagered mountain tapirs of the northern Andes. He has given speeches and written many articles, including encyclopedic, and several books. His works are both popular and scientific, in English, Spanish and translated to German. Several of these concern wild horses, their ecological contribution, their North American evolutionary roots, their great natural and social value and their survival plight. Downer is an Advisory Board member for Protect Mustangs, a member of the World Conservation Union, Species Survival Commission, a Board member of The Cloud Foundation and has written the Action Plan for the mountain tapir (1997). Downer’s current book, “The Wild Horse Conspiracy” points directly to the root cause of the disappearance of America’s wild horses. The book is on sale at Amazon

Observations of PZP contraceptive use in the Pryors

Cross-posted from The Cloud Foundation

TCF does not support or recommend the continued use of the experimental immunocontraceptive drug, PZP, for the Pryor Wild Horse Herd because the drug continues to have an unusual and unpredictable impact on the mares that have received the drug.

PZP treatment was first administered to young females (seven yearlings and one two-year-old) in 2001 when they were given shots in the corrals after a roundup in September 2001. The drug was designed to extend one year of infertility to this group. It was given in two consecutive years. The second year the drug was administered via field darting.

Of these eight young mares, one died and four have foaled. The only two-year-old, Moshi, foaled in 2002, as she was already pregnant. Moshi didn’t foal again for 6 years until her out-of-season filly was born in September 2008.

Of the six remaining yearlings, four have produced a foal. Of the four foals, three were born in September. Administration of PZP was stopped on younger mares in 2005 due to a natural decrease in population largely because of mountain lion predation, and the unexpected absence of foal production by the young mares.

Nearly 50% of the young mares receiving the drug in the years 2001-2004 have never foaled. Of the 34 young mares to receive the drug between 2001-2004, 11 have died, 13 have foaled and 12 have not foaled.  Two veterinarians (from Switzerland and Colorado) have independently expressed the same concern to us: mares not producing foals at a typically younger age (i.e. three-seven years) will have a more difficult time conceiving. They point out that this is true not just in horses but in humans as well as other species.

Of the 13 young mares that have foaled, eight foals have been born out of season, including three in September of 2008 alone. One foal born in September, never grew to full-size and was subsequently bait trapped and adopted out in September 2006. Another foal, born to Cecelia, #2224, a mare darted as a yearling and two-year-old in 2003 and 2004, was born in December of 2006. The majority of Pryor Mountain mares foal from May 15- June 15.She didn’t foal in 2007 and then foaled in September of 2008.

Photo evidence attests to the masculine and aggressive behavior of certain PZPed fillies as well as the masculine appearance of Aurora #2036. She has a stallion-like cresty neck and physique. It is obvious that the hormones of these young mares have been altered by PZP.

Of 21 older mares (11 years of age and older) given PZP from 2003-2007, 57% or 12 mares have foaled in spite of the field darting with Porcine Zona Pellucida. Only 43% or nine mares have not foaled (drug worked as designed).  One mare, Tonopah #8603, produced a foal at the age of 21 in 2007.

Aside from the cruelty of raising a newborn foal going into a Montana winter, the drug has had other negative side effects in the form of abscesses, bleeding, and swelling on the hips of field darted mares. Of the 54 mares listed on the PMWHR Injection and Reaction Observations –updated June 2007 (BLM-03262), 41 mares are listed with swelling, nodules, bleeding or a combination of all these. 20 mares still have visible signs of nodules even years after they were injected. One mare, Hightail #8901, had an abscess from darting in 2007 which has since healed on its own.

Phoenix #9104 had a major wound at the location of an injection site lump from the last field darting prior to the observed wound. Photo comparisons indicate the wound, which appeared in June 2007 matches the left hip nodule from a previous darting with PZP.  (Photos included). The mare and her foal were captured and treated in the corrals at the base of the mountain. Upon release to her band, the abscess looked to be healing although the mare had lost weight while in the Britton Springs corrals. Despite continued weight loss, the mare survived a long winter with deep snow at times, and looks remarkably fit at present.

The BLM has reported that density dependence (the ability for a wildlife population to self-regulate its numbers based on available resources) and compensatory reproduction (over-production by females to increase an under-represented population) have taken place on the Pryor Wild Horse Range. In other words the older mares that continue to reproduce despite the use of PZP are responding to an under-population. Generally the core reproducers as well as the older females share this burden. One older mare, Madonna #8913, who has been darted with PZP yearly since 2003, foaled in June 2007. The foal appeared to have trouble suckling and milk ran out its nose when nursing. The foal likely died during the night, as she was not with her mother the following morning.

To our knowledge this is the only herd in the West to receive PZP via field darts (Assateague Island off the coast of Virginia uses field darts with few reported problems). We believe that the many problems with swelling, bleeding and abscessing may be partially blamed on field darting. The projectile is shot through unclean surfaces on the hips of the mares.

Of the original group of young mares given the shot by hand while in the corrals, only one had any swelling. The other seven had no swelling, nodules or abscesses. This compares with 41 of 54 mares (a staggering 76%) with reported swelling, nodules and bleeding from at least one field darting experience. 43% of the mares darted in 2007 have nodules or bleeding and one mare had an abscess (Hightail #8901).

According to scientific reports, not all darts are recovered. Some needles may break off and remain in the mare where they could cause later abscessing. Significant problems may not be immediately observed, rather bacteria may linger and the problem area might be walled-off for some time then suddenly emerge as in the case of Phoenix #9104. This was mentioned as a possibility by four of the six equine veterinarians with whom we consulted. These veterinarians practice in California, Oregon, and Colorado and were asked for their opinions regarding the efficacy of field darting mares in the PMWHR, the potential hazards of this practice, and the possibility for a late abscess to appear months after the darting.  One veterinarian expressed concern that the mare was darted again, thereby placing more strain on the immune system. Phoenix is one of the older mares who has produced a foal despite being darted.

Ironically, the initial stated reason for the administration of PZP by BLM was “purely from the standpoint of compassionate use”. Compassionate use was defined as “the use of the tool (or in this case a fertility control agent) to improve the quality of life of another (in this case younger or older wild mares).” (BLM Field Manager, Sandra S. Brooks-June 3, 2004). BLM sought to prolong the life of the older mares by causing them not to foal and to delay the foaling of the younger mares for one year.

The stated goal of the scientific community regarding an ideal wild horse fertility control agent was that it should be “at least 90% effective” (Wild Horse Contraceptive Research document, 1991 USGS website, posted 2-21-06). While the drug appears to be over 90% effective on Assateague Island, it has not performed in a similar manner in the Pryors. It has not prevented the foaling by a majority of the older mares and it has prevented foaling by the majority of the younger mares, in some cases, for seven years.

Most importantly, instead of trying to manage the Pryor Mountain Wild Horses in a natural way, allowing for a predator-prey balance and only conducting a roundup when truly necessary, wild horse managers opt for the use of PZP in combination with helicopter roundups and bait trapping. These policies threaten the health of the unique Spanish mustangs of the Pryor Mountains.

In addition to the statistical analysis of PZP use, it is hard not to comment on the social stress placed on both mares and their bands stallions when the mares cycle monthly and are repeatedly bred but do not settle. In July of 2008, we witnessed one young mare (#2315) being bred three times in a fifteen-minute period while she struggled to get away.  Mares that cycle monthly attract the attention of bachelors and other band stallions on a regular basis and the stallion expends energy both in defense of his mare and in breeding her.  This social unrest has not been reported on Assateague Island, but is easily observed in the Pryors, when individual horse bands come in close proximity to each other during the summer months.

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Stop the Roundups Rally in Sacramento July 10th at 2 pm outside the Federal Courthouse

Come to the rally to show that you care about the wild horses and burros in America.

Terri Farley speaks at the Rally to Stop the Roundups (Photo © Anne Novak.)

The Sacramento Stop the Roundups Rally and Press Conference is at 2 p.m. July 10th on the sidewalk outside the Federal Courthouse across from the Amtrak station. ( 501 ” I ” Street at the 5th Street intersection in Sacramento, CA 95814)

Here is a list of speakers:

Carla Bowers, National Wild Horse Advocate

Tina Brodrick, Owner of Sonny Boys Tours

Craig Downer, Wildlife Biologist and acclaimed Wild Horse and Burro Expert

Terri Farley, Award winning writer and beloved author of The Phantom Stallion series

Cat Kindsfather, Award winning wild horse photographer

Marilyn Kroplick, MD, Board President for In Defense of Animals

Simone Netherlands, President of Respect for Horses

Anne Novak, Executive Director of Protect Mustangs

Jetara Séhart, Executive Director of Native Wild Horse Protection & Marin Mustangs

Robin Warren  (Wild Mustang Robin), Director of The Youth Campaign for Protect Mustangs

Bring homemade signs and your friends. It will be hot so bring a rain umbrella for shade and plenty of water. Protect Mustangs encourages members of the public to carpool or take Amtrak to save on fuel and reduce pollution. Oil and gas extraction–on public land–is one of the main reasons wild horses are being wiped off their home on the range.  Be part of the solution and take the train if you can.

The voiceless wild horses and burros need your help after the rally too. Give oral or written comment against helicopter roundups and attend the 6:30 pm BLM Wild Horse & Burro Helicopter/Vehicle Use Public Hearing for roundups and management. The meeting runs from 6:30-8:30 PM at the Woodlake Hotel (formerly the Radisson near Arden Fair Mall) 500 Leisure Lane in Sacramento.

“Like” and check for updates on our Facebook page:

Join the dynamic conversation on Facebook about helicopter roundups:

Driving directions from the rally to the meeting:

Driving directions to 500 Leisure Ln, Sacramento, CA 95815
501 I St
Sacramento, CA 95814
1. Head north on 5th St toward H St
194 ft
2. 5th St turns right and becomes H St
0.8 mi
3. Turn left onto CA-160 N/16th St

Continue to follow CA-160 N
2.3 mi
4. Take exit 47A for Leisure Ln towardCanterbury Rd
0.1 mi
5. Keep left at the fork, follow signs forLeisure
79 ft
6. Turn left onto Leisure Ln

Destination will be on the right
354 ft
500 Leisure Ln
Sacramento, CA 95815

Special thanks to Jetara Séhart, Executive Director of Native Wild Horse Protection & Marin Mustangs for her help to put together this event.

If you have any questions or would like to speak at the rally feel free to send us an email at