The use of the contraceptive agent PZP can seriously compromise the natural adaptation of wild horses, writes wildlife ecologist Craig Downer. This, he suggests, subverts the true intent of the Wild Free Roaming Horses and Burros Act, passed in 1971 to safeguard the animals.
Many serious damaging effects upon wild horses and burros are caused by PZP (Porcine Zona Pellucida) administration. These effects pertain both to the mares who are injected with this inoculation, either manually when held captive or remotely by darting with a rifle in the field aimed at the hip and to the rest of the band whether stallions, other mares or young.
These effects have been documented and analyzed by professional biologists, and many ordinary people have also observed and reported them. An honest reading of the Wild Free-Roaming Horses and Burros Act (WFHBA) should reveal how out of tune PZP interference is, for it violates the most intimate parts of mares and causes an aftermath of stress, anguish and social disruption. It should be considered antithetical to this law’s core intent. Basically, PZP interference with the natural lives of the wild horses (or wild burros) is a form of domestication that contradicts the WFHBA, which mandates “minimum feasible management” and that the horses and burros be allowed to become “integral” parts of the public lands’ ecosystem where they attain a “thriving natural ecological balance”. To those who hold the noble purpose of this law in high esteem, what has and continues to happen is both a shame and a disgrace to America! This is an intolerable situation that needs to be quickly corrected.
Recently, I have been digging deeper into this serious matter. A penetrating analysis concerning PZP, was made by the incisive researcher Marybeth Devlin of Florida to whom I owe so much for her factual analysis and insights. What I earlier wrote about PZP can be perused at here, where Devlin’s work is fully cited.
Some of the most alarming effects of PZP are:
(1) The undermining of the immune systems of the wild horses over the generations. This sets them up for decline and die-out due to disease, inclement weather or other stressful situations.
(2) The serious stress and discontent experienced by the PZPed mares in not being able to complete their natural reproductive life cycles. This leads to their frustrated rejection of stallion after stallion.
(3) The disruption of the social bands and their hierarchies because of the above, which throws both the individual bands and, consequently, entire herds into disarray. This breakdown of education passed from the older stallions and mares to their progeny affects their ability to survive in the long-term.
(4) The lack of customary reproductive inhibition of younger by older horses, as occurs in mature and natural horse societies, throws the social order into disarray and negatively affects the survival ability of the horses. (The same applies to burros.)
(5) The out-of-season, deformed and stillborn foals documented to be born (or nearly) from those mares who are coming off of PZP. This has been reported by scientists as well as ordinary concerned citizens. And the list goes on!
Many of the biologists who have observed the detrimental effects of PZP have warned of these and other adverse effects, usually in a non-emotional, objective and professional way. But we should not confuse their intellectual style with a lack of concern and even alarm. One recent article that was co-authored by five leading equine biologists has this to say: “Careful consideration to the frequency of PZP treatment is important to maintaining more naturally functioning populations; the ability to manage populations adaptively may be compromised if females are kept subfertile for extended periods of time.”
Also: “… the use of PZP with small populations and/or those of conservation concern should be approached with caution (Ransom et al., 2014).”
And again also: “… the fact that mares do not easily return to fertility after the cessation of treatment could limit the ability of populations to rebound in the face of stochastic declines. In the case of Shackleford Banks horses, prolonged PZP-induced subfertility has likely reduced the ability to adaptively manage the population; stopping treatment has not resulted in increased fertility, particularly for mares that previously received 4+ treatments.”
While the article does not make a point to fend for the wild horses, its revealed facts indicate that PZP can seriously compromise the natural adaptation of wild horses to each particular ecosystem, which would be a subversion of WFHBA’s true intent and purpose. Clearly, when we humans thwart the ability of the horses to naturally adapt to their surroundings, and when we replace natural selection with artificial selection by humans concerning which individuals survive and procreate, we are domesticating these horses and creating a disharmonious situation. And this is contrary to the WFHBA!
As I reviewed the wild horse population and removal statistics from the BLM in their report of March 1, 2019, it became increasingly obvious that the very wild horse herds that have been most heavily PZPed and for the longest durations are still being rounded up and taking drastic cuts in their numbers. Also, the above quoted caveat about PZPing small, genetically sub-viable herds or rare endangered lineages is not being heeded. And this concerns such living treasures as the Curlies (still found in parts of eastern Nevada and western Utah but rapidly being removed) or the purer Spanish Mustang herds, e.g. Montana’s Pryor Mountain herd. The following are but a few of the many herds throughout the West (as elsewhere) whose future on Earth is being jeopardized by PZP injection and other crude means that are heavy on “management” and lacking on “protection and preservation”.
Pine Nut Mountain wild horses
In Nevada, a herd both near and dear to me consists of the ever-fascinating Pine Nut Mountain wild horses. But it has just been “gutted” by BLM contractors — drastically reduced by 575 in spite of several years of PZPing the mares. BLM officials have just played a dirty trick on many of us local citizens as well as outside visitors who love these unique horses. As the studies of equine geneticist Gus Cothran reveal, these preserve a unique mixture of significant Spanish Mustang as well as other breeds, such as the shorter ponies, including Shetland, used in pulling out ore carts from mining tunnels in the Virginia Range just to the north, where the world-famous Comstock Lode occurred. Pine Nuts’ original legal Herd Area (HA) is 251,792 acres, but it has been reduced to 104,316 Herd-Management-Area (HMA) acres.
The Appropriate Management Level (AML) is only 118 to 179, for a mean of 148. BLM gathered 340 “excess” wild horses between February 7 and 20, 2019, and began its second phase of gathering on July 29. In my professional opinion as a biologist, by reducing the population to 118 and continuing heavy PZP darting of the mares here, this herd – one special and even beloved by so many – would become seriously endangered. At the mean AML of 148 horses, there would be 705 HMA-acres and 1701 original HA-acres per individual horse. And, yet, Section 2 ( c ) of the WFHBA clearly states that the legal Herd Areas shall be “devoted principally” to the wild horses, or wild burros, NOT to ranchers and their livestock, miners, energy developers, off-highway vehicle (OHV) users (very serious in the Pine Nuts), big-game hunters, loggers, woodcutters, etc. Yet this is precisely what continues to happen! Some have called this a “travesty of justice” and I would certainly agree! (Ask me for my extensive investigative reports concerning the Pine Nut herd and habitat.) Two links that can immediately provide you with revealing facts and insights into this beautiful and venerable historic herd and its biologically rich as well as spectacular habitat and the struggle to save such are to be found here and here.
Montana’s Pryor Mountain herd
Another heavily PZPed and cherished wild horse herd with a high degree of Spanish Mustang is the Pryor Mountain herd in the state of Montana. This is the last remaining of seven original 1971 herds, all of which should have been given protection by the WFHBA. Six of these have simply been zeroed-out, though they are still legal Herd Areas, but totally victimized ones because of scruple-less, uncaring and often mendacious people. The Pryor Mountain itself was declared “national wild horse range” several years before the December 1971 passage of the WFHBA. It contains 44,920 original HA-acres, but sometime after 2003, when I visited the herd, this was cut to only 35,640 HMA-acres by the Billings, Montana BLM District Office. This very unjust “squeeze play” has to do with a lengthy Log-and-Pole fence that very effectively keeps horses from occupying their legitimate summering meadows on Custer National Forest grounds. These beautiful, highland meadows benefited from the horses, as they are natural enrichers of soils and dispersers of germinable seeds of a great variety, including native species. But USFS officials have sided with those who target the horse as being non-native to North America, though nothing could be further from the truth. The horse species greater story upon Earth is that they are ancient and deeply rooted natives in North America, where they have been present for millions of years and that, as a consequence, their restoration as truly genetically viable populations in truly longterm viable habitats actually restores hundreds even thousands of plant and animal species with which they have co-evolved for literally thousands of generations.
It was my privilege to visit this herd in June 2003, back when it still occupied the highland meadows. I even witnessed the famous cremello stallion known as “Cloud” and his lively band. The meadows near where they stood were lush and thriving and, to a large degree, due to mutualistic contributions made by these naturally living horses. I also observed a puma chasing his prey (which includes horses but in this case was a deer) at quite a near distance at the edge of a pine forest. I could sense the electricity of this age-old drama in the very air! Besides one brief visit in early 2015, later in June 2016, I returned to observe this herd and do an ecological evaluation of its habitat. This herd had since been heavily PZPed and was not nearly as lively nor in as exuberant a state of health as before. To me, they are clearly well into the process of being domesticated – which is contrary to the true and core intent of the WFHBA. My revealing protest letter and related investigative report both seek to restore this herd to a genetically viable population level and allow them back into a complete year-round habitat, as existed in 1971.
The egregiously low AML for this nationally and internationally cherished herd appears to have been dictated by a local rancher. It goes from a low of 90 to a high of 120, with a mean of only 105 wild horses. This means that BLM is allowing only one individual horse for every 428 acres of original HA land and every 339 reduced-HMA acres. Given how much more rainfall and how much more productive the Pryor Mountain ecosystem is compared to so many of the more arid regions of the West, such arbitrary assignments constitute an outrageous injustice to these naturally living horses. They possess a right to not only live but to thrive here, but given the intensive PZPing of the mares, they are being set up for inbreeding and a decline of the requisite natural vigor that it takes to survive over the generations.
BLM currently reports there are about 162 wild horses in the Pryors, and they have been repeatedly trying to again reduce their numbers to the abysmally low-level AML. Also, my inspection of the Pryor Mountain Wild Horse Range (PMWHR) indicated considerable invasion of the sanctuary by cattle, especially along the borders, and too much disruption of the habitat by OHVers (off-road highway vehicle drivers)! The PMWHR is visited by a steady stream of ecotourists throughout the year, and there is even a wild horse tour operation out of the Mustang Center located in Lovell, Wyoming. My impression of this situation is that these uniquely beautiful and historic, largely Spanish Mustangs (related to the Crow Native American herds and possibly to the Lewis & Clark expedition) are being smugly cheated of their rightful land. They deserve more ample freedom and must not be rendered into a frustrated, mere token remnant of what they once were. But the good news is that this deplorable and sick situation need not continue. For, if only the WFHBA were honestly and caringly enforced, these wonderful wild horses could be restored to a population level that is commensurate with the wholesome ecological niche that exists for them in this awesome mountain range (in and around which are found horse fossils dating from centuries to millennia or even millions of years before civilized Europeans arrived here, thus proving the horse’s preexisting niche).
Utah’s Onaqui Mountain herd
Another popular though heavily PZPed wild horse herd occurs on Utah BLM land west of Salt Lake City. This is the pulchritudinous and diverse Onaqui Mountain herd which I visited in mid-June 2019 right after attending a rally for wild horses, wolves and endangered wildlife on the steps of Utah’s state capitol. Nearly all the mares had been PZPed and bore disfiguring brands on their hips. The original HA contains 507,681 acres but the wild-horse-occupied area has been reduced to 240,153 HMA–acres and assigned an unjustly low AML of between 121 and 210 for a mean of 166 individuals. So, at the moment there are a whopping 3058 HA-acres per individual horse and 1447 HMA-acres per individual horse! One would think that if nearly half of the original legal HA-acres were zeroed-out (i.e. wild horses eliminated therefrom) then in the remaining HMA-acres, the wild horses would definitely be treated much more fairly. — But NOT SO! Still they are being targeted and denied their rights to an adequate population and the ability to fill their important ecological niche.
The most recent BLM roundup of the internationally famous Onaqui mustangs occurred on September 19, 2019, and resulted in the removal of 241 wild horses. Clearly the lesson here is that heavy PZPing does not guarantee that our precious and scant remaining wild horses shall be left in peace to occupy their rightful habitat. Rather these continue to be largely monopolized by ranchers’ livestock that strip most of the forage and then are removed for consumption by humans, thus robbing the natural ecosystem where most species contribute their mortal remains after death and are recycled back into the life community that supported them all their lives. Again a classical case of the disharmonious extractive way so-called “civilized” humans destroy the age-old natural order that is exquisitely balanced in every detail and includes the wild horses.
By the way, at least two of the Onaqui mares who were recently rounded up died from roundup-related injuries, despite the ongoing intensive mare-PZPing program in this large HMA. I pray their unique lives and suffering – their true and complete stories – shall be heard and that justice for all, including them, shall some fine day prevail.
Oregon’s Kiger mustangs
Another cherished group of quite pure Spanish heritage that should be preserved is the Kiger Mustang Herd. It is to be found at the northern end of the majestic Steens Mountains and is under the jurisdiction of the Burns BLM Office in central south-eastern Oregon. On several occasions spanning over a decade, I visited and photographed these spirited beauties in their legal HMA, but so few of them remain at present; and their HMA is largely given over to ranching and hunting interests. So I am sad to report that their legal area is fraught by fences and cross-fences, overwhelmed by cattle and overly manipulated to favor deer hunters. However, I was lucky to observe a couple of bands during my last visit there a few years ago. As indicated in my report (see link below), OHVers are really tearing this HMA up, as are cattle, though the latter through no fault of their own.
According to BLM’s March 1, 2019 statistical report, this HMA contains 30,305 acres with an established AML of only 51 to 82 for a mean of only 66 individuals, which corresponds to 459 HMA-acres per individual wild horse. This AML is far below true genetic viability; and, though the Burns BLM office claims it will remedy this situation by combining the Kiger herd with the nearby Riddle Mountain herd, the latter 32,666-HMA-acre HMA has an assigned AML of only 33 to 56 wild horses, for a mean of 45 (one horse per 726 acres). So even in combination, there would only be 111 wild horses, which is far below genetic viability.
And though 150 is often used by BLM as being minimally viable, an objective estimate by the Equid Specialist Group of the IUCN Species Survival Commission (to which I belong) is 2500 individuals for the long-term survival of wild equid species. (Duncan, Patrick. 1992. Zebras, Asses, and Horses: An Action Plan … IUCN SSC, ESG. Gland, Swit.)
In their March 1, 2019, report, BLM indicated 91 Kiger mustangs and 79 Riddle Mountain mustangs still being present. PZP injection of mares would clearly jeopardize the future genetic heterogeneity of this tiny remnant of Spanish mustangs, placing it at severe risk of inbreeding, decline and die out. Yet, this sort of treatment is typical of BLM. And if you think the situation here is serious, consider what the Burns’ BLM office did to the nearby Warm Springs wild horses and wild burros within their 499,457-acre HMA. They recently rounded up nearly all of the about 1000 horses and burros here. They then reported there were 30 wild horses and 30 wild burros left in this immense area, which is tightly fenced and cross-fenced to accommodate a true monopoly by cattle ranchers. The captured wild horses and burros languish in the Hines BLM Holding Corrals (which I visited and photographed). Ever since the massive roundup, BLM officials have been continually trying to get approval to do gruesome and unsanitary in-field spayings (called ovariectomies by colpotomy), geldings and other Frankensteinian procedures that are totally contrary to the true spirit and intent of the WFHBA.
PZP could also be part of their reprehensible plan, a plan that could only be hatched by persons who have abandoned their sworn oath to uphold fairly and equitably all the laws of the United States of America in order to favor the wild horses’ and burros’ worst enemies. To gain further insight into the ongoing plight of these wonderful, though victimized, horses and burros, read my complaint to BLM.
Wyoming’s McCullough Peaks herd
Another herd of heavily PZPed wild horses I have visited is Wyoming BLM’s McCullough Peaks herd. These occupy an HMA of 120,412 acres, but have an assigned AML of only 70 to 140, for a mean of, again, only 105. And this is neither a prescription for genetic viability nor for the mustangs being allowed to fill their legal and natural niche here. Currently reported to have 164 horses left, this herd was recently rounded up in January of 2016. When I visited this herd in late June, 2016, I observed some very stressed out wild horses, particularly one stallion that I saw performing some nervous “displacement behaviors,” including frantically pawing the ground. He was off by himself, sweating profusely and very shaky and trembling. I truly sensed his profound misery, and my heart went out to him. As indicated earlier, wild mares who have been PZPed often reject one stallion after another when they fail to conceive. And this creates much anguish and stress for all concerned, including the rejected stallion. To me, this is the exact opposite of what the WFHBA intended and still intends; and for this reason I am proposing Reserve Design as the true “way or path forward” – the true and honorable wild-horse-and burro-respecting implementation and fulfillment of the WFHBA.
My ongoing Reserve Design project, which I have been working on since 2015, does not involve the very invasive PZP darting or other disruptive and disrespectful ways of “managing into extinction” these wonderful “national heritage species,” returned North America native species, and unique and wonderful conscious presences – most of all.
Colorado’s wild herds
Before closing, I would be renege was I not to mention a couple more distinguished herds from Colorado. The first being Colorado’s Sand Wash Basin wild horse herd. This is another that has been heavily PZPed and, yet, where BLM continues to round up the wild horses. About 92% of the forage in this HMA goes to sheep ranchers. There are 156,502 HMA acres here, but the AML is only between 163 and 362, for a mean of 263, corresponding to 595 acres per individual horse. There is relatively high forage productivity here due to greater precipitation than in more arid areas of the West, so there should be considerably more horses. But the problem is getting the ranchers to cut back on their livestock. This is a famous herd visited by thousands of ecotourists with cameras and telephoto lens, and it is famous among wild horse photographers.
The famous Medicine Hat stallion Picasso resides here and is, indeed, a majestic presence, as I recall from my visits. Yet, in spite of this being a very treasured herd, the horses continue to be tortured and their future jeopardized by the heavy PZPing of mares and frequent herd-gutting roundups. By the way, these herd-gutting roundups also greatly increase the risk of catastrophic wildfires, since the horses are no longer in adequate numbers to reduce dry flammable vegetation. Consequently, often shortly after these roundups, there occur devastating and widely sweeping wildfires. This link has been proven in many states throughout the West. (See my book The Wild Horse Conspiracy for examples or from me via my website at www.thewildhorseconspiracy.org.)
The second herd of concern in Colorado is the Little Book Cliffs Wild Horse Range. It has an HMA of 190,016 acres, but an AML of only between 90 and 150 for a mean of 120 horses, corresponding to 1583 acres per individual wild horse. Though this is nearly a wild-horse-empty habitat, within their legal HMA this unique herd, which contains many gorgeous palominos, is supposed to be the principal recipient of resources, space, water, forage, shelter and other survival requirements.
Little Book Cliffs’ mares have been PZPed for many years, which has caused serious inbreeding risk. BLM officials have responded to this admitted risk, by bringing in horses from outside to breed – but this waters down the precious genetics of this special and historic mustang lineage. And some serious signs of inbreeding have already been reported by frequent observers. For this reason, I propose these outstanding mustangs be protected under the Endangered Species Act as well as the WFHBA so that this unacceptable situation can be remedied by people who actually value and care for these horses.
Other examples of PZPed herds and their continued roundups, over-fencing, restrictions from water sources and general unfair treatment are to be found throughout the 10 Western states where BLM and USFS still “manage” for wild horses and burros. These agencies’ reports make it difficult to get at the greater picture concerning what is actually happening, so FOIA requests have been made to expose what is wrong with this publically valued program in order to quickly correct it and save the horses and burros from oblivion. They must be restored to their rightful land and freedom and at long-term viable population levels with commensurate viable resources.
Bills such as ROAM (Restore Our American Mustangs) introduced by Arizona Representative Raul Grijalva have nearly passed (2009), but so far the smug cabal of public lands ranchers has shamelessly crushed every further attempt at remedy. A current bill seeks to reduce the public lands rancher monopoly, and it is my hope that it will succeed, perhaps after this year’s crucial election.
Meanwhile, BLM continues to drastically cut the herd populations and zero out more millions of their legal habitat acreages.
For the sake of these magnificent presences we call wild horses and burros and their right to live freely and naturally as viably sized populations within viable habitats where they are allowed to harmoniously fill their beautiful age-old niches and play their benign roles, I remain, one of many proud wild horse defenders, and one who knew and worked with Wild Horse Annie of ISPMB.
A pioneer-descended Nevadan, as a boy Craig Downer fell in love with the natural world, oft while riding his best friend Poco. This passion led him to pursue a career in wildlife ecology and to earn an A.B. in Biology with specialization in Ecology from the University of California-Berkeley, an M.S. from the University of Nevada-Reno, and to attain Ph.D. candidature at Durham University in Britain. His studies and observations of wild horses led him to work with Wild Horse Annie in insisting that the true intent of the Wild Free-Roaming Horses and Burros Act be implemented throughout America. He served as a Peace Corps wildlife ecologist in Colombia and is the first biologist to have successfully captured, radio-collared and tracked the endangered Mountain, or Andean, Tapir as part of his doctorate studies, His organization, the Andean Tapir Fund, continues to successfully defend and protect this dwindling species, along with its diminishing cloud forest and paramo habitats. He is a member of the IUCN Species Survival Commission and his organization works to save all members of the Horse, Tapir and Rhino families (Order Perissodactyla) in their natural habitats. Visit Craig’s website.