Why PZP and wild horses do not belong together

A band of Kiger mustangs on the range. The Kiger mustang is a strain of mustang horse located in the southeastern part of the U.S. state of Oregon.
A band of Kiger mustangs on the range. The Kiger mustang is a strain of mustang horse located in the southeastern part of the US state of Oregon. © Craig C. Downer

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!

Attention All: Wild horses on the Flowery Range in Nevada. The area is a mountain range associated with the Virginia Range in Storey County, and is named on account of wildflowers which bloom when watered by melting snow.
Wild horses on the Flowery Range in Nevada. The area is a mountain range associated with the Virginia Range in Storey County, and is named on account of wildflowers which bloom when watered by melting snow. © Craig Downer

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”.

A wild stallion from the Pine Nut Mountain area of Nevada. 
A wild stallion from the Pine Nut Mountain area of Nevada. © Craig C. Downer 2017
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.

Pryor Mountain wild horses on the Montana-Wyoming border.
Pryor Mountain wild horses on the Montana-Wyoming border. © Brad Purdy, BLM Montana/ Dakotas
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.

Pryor wild stallion Cloud.
Pryor wild stallion Cloud. © The Cloud Foundation

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).

Wild horses at the Sulphur Herd Management Area in Utah before last winter's Bureau of Land Management helicopter roundup there. © Steve Paige.
Wild horses at the Sulphur Herd Management Area in Utah. © Steve Paige
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.

A wild horse in the Kiger Mustang HMA in Oregon. © Craig C. Downer
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.

Wild horses in the BLM's McCullough Peaks herd management area.
Wild horses in the BLM’s McCullough Peaks herd management area. © 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.

Horses in the Sand Wash Basin Wild Horse Herd Management Area in northwestern Colorado.
Horses in the Sand Wash Basin Wild Horse Herd Management Area in northwestern Colorado. © BLM
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.

Raúl Grijalva
Raúl Grijalva

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.

Craig C. Downer

Craig C. Downer, Wildlife Ecologist, A.B. (UCB), M.S. (UNR), Ph.D. C. (U. Durham-UK) P.O. Box 456, Minden, NV 89423 USA. Cell. (775) 901-2094

29 thoughts on “Why PZP and wild horses do not belong together

  • March 24, 2020 at 12:09 pm

    A very interesting and humane approach to the wild horse issue. I am impressed with the detailed information and research behind this article. I wish every government person involved with these animals would listen to what is being presented. Most importantly, I wish we as humans would treat these magnificent animals with the respect any living being deserves. Thank you for this article. I, too, am a supporter of free and wild horses….of the historic lineage they represent. They bring much joy to many of us, and we will continue to fight for their freedom and right to live naturally.

    • March 28, 2020 at 9:19 am

      Thanks so much for supporting — and recognizing the true importance of the naturally living burros, Sharon. This is what is so sorely lacking among too many today. But the good news is that we can change this. We must! They deserve it and so does our world …

    • July 20, 2020 at 4:14 am

      This was a pleasure to read and the absolute evidence of what “Our government “ is actually doing on a daily basis. Are our tax dollars PayIng their continually raising wage and benefit package?
      I say
      IF EVERYONE sent this reminder to each politician and those running running for office in their state, By BOTH email AND email. Post it on all their media page(s) Ask your paper to run this rebuttal – Ten maybe they would get the message!
      Let’s make EVERYONE aware!
      It certainly wouldn’t hurt.
      Involve children with and essay or story about “their wild mustangs or burro?!

  • March 25, 2020 at 12:21 am

    MORE EXPOSURE is needed for this important issue! Why can’t we take more time in our days to cooperate with each other fully to resonate our collective voices in order to effectively DEMAND RESPECT for these magnificent, historic creatures?!? I can fully appreciate the amount of research Craig Downer has achieved and agree with him that we should not mess with the biological functions of protected wild horses in their native habitats as much as the only alternative to their survival is deforming their natural functions to control their numbers to prevent their removal and genocide. I know Craig personally and have spent considerable time advocating for our Nation’s horses publicity alongside him. I also know Neda DeMayo and have personally observed the herds unturned at Return to Freedom American Wild Horse Sanctuary in California. I have seen PZP, properly administrated, be used successfully as a tool for management. That said, I do NOT appreciate the defamatory statements made by some advocates who seek to divide our impact through negative in-fighting and squabbling over the PR generated to gain charitable dollars. I feel that our COLLECTIVE VOICE MUST have an appreciation for the power exhibited over this issue by our Government and our LACK OF EFFECTIVE MEDIA EXPOSURE. I have organized and completed multiple rides for exposure against commercial horse slaughter as an industry. Who is up for an organized ride to Save America’s Mustangs? Who is up for putting down the pitchforks and coming together as a legitimate, organized movement to gather an effective appeal to gain the help of an A-List entertainer/activist like PINK or Ellen DeGeneres??? I have some connections which I have developed for years since my solo ride to Hollywood in 2011 and I am willing to collaborate on a project that will garner some real results for the exposure of this issue through major media and to the general public at large. I challenge anyone who is a top-level advocate to contact me directly at karin@horseactivist.com so we can start a dialogue that can eventually help take this issue into the mainstream to give these invaluable animals a real, effective voice in this modern age.

    • March 28, 2020 at 9:34 am

      Thanks for your well-rounded comment, Karin, and for recognizing the validity of much of what I have presented. I agree with you that we must band together to insist on a greater recognition of the true value of the naturally living burros and horses and would be certainly willing to join together in actions that are aimed at achieving a real breakthrough for much better and fairer treatment of these nationally protected wild equids IN THE WILD (something that is being sorely neglected). A special ride to gain publicity could go a long way and I grew up on a wonderful horse POCO and have ridden horses, mainly, but also mules and even burros throughout my life and they greatly helped me in my various conservation projects, especially those aimed at saving the endangered Mountain, or Andean Tapir (see https://andeantapirfund.com). I strongly urge people who care about the true fulfillment of the WFHBA to support H.R. 5737, the Volunteer Grazing Permit Retirement Act, that was set into motion on Jan. 30, 2020. It would retire grazing permits on a voluntary basis so that the wild burros and horses can get more of their legitimate forage, space, water & other survival needs as truly long-term viable populations, not mere token and semi-domesticated remnants crippled and merely there for show. You can contact your Representative and Senator at http://govtrack.us or by calling 202-224-3121. Thanks and stay safe and well! Take precautions against Corona.

  • March 25, 2020 at 1:28 am

    Why wasn’t this release to the public before by blm? Why so many secrets? I believe that the department should be investigated & fired if seen fit! When is the public going to be properly informed of side effects & actual thinfs tgat happen? We have to revamp the system.

    • March 28, 2020 at 9:37 am

      I so agree, Walt! Why are BLM officials ignoring the obvious and the scientifically proven? We must speak up and stand up and ACT to change the situation and stop the persecution of the wild naturally living burros and horses. As with so many things in life, if we don’t care enough to stand up and insist on the greater truth and justice, then the consequences are tragic. The wild horses and burros of America are worth the effort.

  • March 25, 2020 at 8:35 am

    So for those of us who are still learning … what is a “pesticide” versus a “vaccine”?
    By definition, a pesticide is a product designed to DESTROY organisms deemed to be undesirable or noxious.
    PZP or brand name ZonaStat-H, EPA Reg. NO. 86833-1, was approved for use in wild burros and horses by the EPA. ZonaStat-H is a PESTICIDE, registered in January 2012 by The Humane Society of the United States.

    Chemical or biological substance designed to KILL or retard the growth of pests that damage or interfere with the growth or crops, shrubs, trees, timber and other vegetation DESIRED BY HUMANS. Practically all chemical pesticides, however, are poisons and pose long-term danger to the environment and humans through their persistence in nature and body tissue. Most of the pesticides are non-specific, and may kill life forms that are harmless or useful.
    Any preparation used as a preventive inoculation to confer immunity against a specific DISEASE usually employing an innocuous form of the disease agent, as killed or weakened bacteria or viruses, to stimulate antibody production.

    PZP is NOT a vaccine … it is a PESTICIDE.

    The BLM and USFS & HSUS make it sound like they are helping to prevent a disease when they are actually supporting the eventual demise and extinction of our wild horses and burros.
    See for yourself:

    • March 28, 2020 at 10:00 am

      Thanks for your comment, Kathy. It is true that PZP is classified as a Pesticide by the FDA. There would definitely seem to be a reason for this, since the implication is that the wild horses and burros are pests in America. My investigations and that of others do indicate that PZP has a very harmful effect especially concerning their long-term survival in the wild. That said, the PZP vaccine is injected by a jab stick or via a dart shot from a dart rifle and then enters the blood stream to produce its effects on the ovaries of the female wild horses and burros. From my trusty Tormont Webster’s Illus. Encycl. Dictionary I get this definition of “vaccine”: “a suspension or attenuated or killed disease-causing microorganisms, viruses or bacteria, incapable of inducing severe infection but capable, when inoculated, or stimulating the production of antibodies (and therefore conferring immunity) against the virulent microorganisms.” And a “Vaccination” is defined as: “an innoculation with a vaccine in order to protect against a given disease.” From my readings and listening to veterinarians and other fellow biologists on this subject, the PZP vaccine that is derived from pig ovaries upon innoculation / vaccination tricks the equine reproductive system into treating sperm as foreign invaders (like disease germs) thus preventing conception, i.e. union of sperm with egg to initiate the development of a newborn — a truly miraculous process! Now I have studied and observed much during my career as a biologist, including physiology, and as a professional, it concerns me that this invasive interference with the mares’ and jennies’ reproductive system would have serious related consequences that affect both the well being of the individual females and the equid social groups to which they belong. And much evidence has and continues to be revealed that this is, indeed, the case. Because the individual horses and burros do not speak our language, those of us who appreciate and care from them must listen to what their own lives and bodies tell us — and we must speak out and stand up on their behalf!

  • March 25, 2020 at 2:21 pm

    God bless you, Craig Downer, for all the wonderful work you do to save our wild horses. I am certain you have made an impact..Things would, no doubt, be even worse for them if not for you..I am so honored and blessed to call you my friend..I miss the days of fighting, in person, with you at our rallies in Nevada..I am going to share this now to my almost 5000 friends on Facebook..I want to help this information get out to the masses..Stay safe and healthy during this turbulent times..We must never give up the fight for our wildlife..particularly our wild horses and our wolves.

    • March 28, 2020 at 10:06 am

      Thanks so much, good friend! I greatly appreciate your support. Yes, was great when you were here and we participated with so many in demanding justice and fair recognition of the great value of the free and naturally living horses and burros on their rightful legal lands. Hope you can come out again to see the wild horses and burros and wolves too. All are now under severe attack by unscrupulous and selfish people who seem to worship money and to turn their backs on the Great Rest of Life, aka Nature, that in fact makes like possible for us humans. We must not give up on this Sacred Cause. We must learn true Reverence for Life — All of Life, not just our own human kind. Take good care of yourself in these dangerous times and keep up your wonderful singing!

      • September 25, 2021 at 3:44 am

        I’ve been getting an education here reading about this drug (pesticide ) as you call it. Did not know that is what they use for birth control. I am sure most people don’t know it either. Disgusting! Truly the BLM has failed us. The slaughter of these noble magnificent animals continues. Objects are more important to most people than living creatures. Money and power is the main factor of this situation. This has been going on for years Cattle verses Horses ! It will take a miracle to change the minds of this whole situation. I love these wild Horses and don’t want to see them disappear. The Horse helped build this country to where we are now. Some still work in the fields today. I hope changes are made soon or all will be forgotten. Thank you for your research to let us know the real truth what’s going on.

  • March 26, 2020 at 12:38 am

    Please save our beautiful Wild horses! Forget the cattle ranchers cattle. If they can’t afford the land to graze them on they don’t need them!

    • March 28, 2020 at 10:09 am

      Thanks Dajaun! You’ve got that right! The cattle and sheep ranchers and other public lands exploiters must learn to share the land and freedom with the magnificent horses and burros, who have legal right to live on these lands, while the ranchers do not possess these same rights only cancellable privileges. There is too much corruption among those sworn to protect the wild horses and burros IN THE WILD!!!! We can change this and we must persist. It is very important that we do so.

  • March 26, 2020 at 9:06 am

    Totally wrong info on the Sand Wash Basin HMA. We have NOT had a roundup in 12 years. A small gather of 43 horses took place in 2016. To date we have NO known cases of deformities as suggested. I have personally been involved with this herd for 20 years and have carefully documented the bands for the last 10 years. Non producing mares do NOT leave the bands. Because of the overpopulation we see mares stolen by younger stallion groups, sometimes 3 or more younger stallions harass the band til the band stallion is injured to the point of requiring euthanization. Foals are injured and left behind each year due to stallion stress. Of the 5 sheep ranchers holding grazing rights in the HMA only 2 even use any of the land now. Due to the overpopulation of the HMA water had to be hauled in a couple years ago. PZP may not be the perfect solution but it’s the best we have for now. Just in the last 5 years we have prevented hundreds of foals that will NEVER have to be rounded up or shipped. Fact is there is little need for horses in our society today therefore few adopters to make homes for these beautiful icons of American history.

    • March 28, 2020 at 10:42 am

      Thanks for sharing your experience with the Sand Wash Basin wild horses, Patti. I stand to be corrected where this is justified and appreciate your update. But, the removal of 43 in 2016 does sound like a “roundup”. And, in general, I am still very concerned by the detrimental effects of PZP and what it is doing to the mares and other members of their bands and the overall population, or herd, in general, and over the long haul of generations. There are a number of professional investigations and reports that show there are serious problems with PZP, including the professional study described in the comment below. I think it is important to have independent observers, not just people who have a vested interest in maintaining the status quo or are overshadowed by such. It is important to our integrity as a nation that we give the wild horses their due under the WFHBA, not treat them with short-shrift, as is the case in almost every HA/HMA (BLM) & Territory (US Forest Service) in our nation. By again looking at the March 1, 2019 BLM statistics I see that the last Gather was, indeed, November 2016, and that the estimated horse population is 621. This makes it the largest existing wild horse population in Colorado, which reports having a total of only 1,429 wild horses remaining in its 4 legal HMAs. (Remember the IUCN SSC Equid Specialist Group recommends 2,500 interbreeding individuals for viability in the wild.) I hope the BLM leaves these 621 horses alone and allows them to fill their naturally justified ecological niche in this scenic area where they contribute so much that is truly positive to all of life, including us humans. And I wish they would give my Reserve Design proposal some serious consideration, for a change. I remain very much opposed to the monopolization of this HMA’s forage and other resources by livestock, etc. and am quite disgusted with the continued dishonorable targeting & scapegoating of the wild horses. Let’s get the populations up to truly long-term viable levels, not cave in to those who want to minimize their populations and relegate them to non-viable unnatural levels and domesticate them. Funny how in their various assessments it is rare our public servants actually spell out the relative proportions of livestock versus wild horses or burros as to forage consumption, etc. This is dishonest and devious and has got to change!

    • May 12, 2021 at 1:22 pm

      The band harassment is increased in a pzped herd. A mare that has been pzped still goes into eustress although does not have a viable egg to be to be fertilized. A nursing mare may or may not go into eustress, thus it has been shown in some herds where a mare may nurse upto 4 years with 1 and a half in average. Also, in a remote herd investigated by the national acc. of Sc. observed when “Left alone” the horses eustress cycle will respond their environmental conditions, or not having a cycle at all when they are at maximum levels to in balance with their land. Taking horses out, giving them pesticide to alter cycles and male behavior, predator losses, less foliage resources in a given year all are factors that determine how much the population will grow or sustain. Hauling water is necessary during drought, a drought that lowered much of Colorado’s reservoir in 2017 and 18 but are starting to revive.
      The real threat in the Sand Wash is the Land plan of permitting thousands of well pads and increasing the number of vehicles crossing the land. I have seen sheep there photographed so did not know some have retired allotments.
      The BLM does not want to do the work of evaluating factors. They know how to dart, roundup, hold, and handle them like livestock. But, they do not know how to or want to become or even hire specialists in zoology, naturalist, ecology because they are Afraid of losing approval from the Other interests.

  • March 27, 2020 at 6:26 am

    Title: The Effects of Porcine Zona Pellucida Immunocontraception on Health and Behavior of Feral Horses (Equus caballus)
    Authors: Knight, Colleen M.

    Advisors: Rubenstein, Daniel I.

    Department: Ecology and Evolutionary Biology
    Class Year: 2014

    However, three or more consecutive years of treatment or administration of the first dose before sexual maturity may have triggered infertility in some mares. Inducing sterility, while relieving the mares from the energetic costs of lactation and reducing the stress from harem switching, may have unintended consequences on population dynamics by increasing longevity and eliminating the mares’ ability to contribute genetically.
    A recent study showed that treated mares received 54% more reproductive behaviors from stallions than the untreated mares. The cumulative effects of this practice are unknown and could negatively impact the natural social behavior and band dynamics in the HMA. The BLM has not provided any reference to current scientific literature.
    The proposal fails to rely on current scientific research that provides results of the cumulative or negative impacts for wild horses by implementing PZP immuno-contraception control. In addition to the social disruption, the proposed action will impact fecundity rates, and impair the natural selective processes for the wild horses remaining in the HMAs.
    Furthermore, this drug has been listed by the U.S. Environmental Protection Agency as a PESTICIDE and our publically owned wild horses and wild burros are NOT pests! http://www.epa.gov/pesticides/chem_search/reg_actions/pending/fs_PC-176603_01-Jan-12.pdf

  • March 28, 2020 at 10:47 am

    Thanks so much for providing this very important information based on rigid scientific observations and analysis by biologist Colleen M. Knight and overseen by one of the world’s leading horse biologist, Dr. Daniel L. Rubinstein whom I have met and heard speak. This bears out some of the important concerns raised in my article. It is imperative that those of us who care about the future of the naturally living horses and burros present such information both to people in positions of authority and to the public so that much needed reforms can take place to restore these wonderful animals to their rightful land and freedom.

  • March 30, 2020 at 5:15 am

    I am so angry and feel so helpless to help these I innocent horses

    • April 10, 2020 at 5:53 pm

      Where there’s a will and clear vision of what is right, there’s bound to be a way, Georgia. Just have patience and doggedness to keep trying to rectify the situation. Happy Spring, season of life’s renewal! (north of the equator)

  • April 9, 2020 at 10:00 am

    Please everyone just leave our American wild horses alone!! We Americans won’t stand for it. Correct BLM, not horse populations. WE own you BLM. You work for all Americans that want to see American traditions continue. Let special interests worry about special interests! Leave wild horses be.
    Free horses on public lands is necessary and normal…

  • April 10, 2020 at 5:47 pm

    Thanks Peri for standing up for what’s right for the “wild” meaning naturally living horses in their rightful legal and appropriate habitats.

  • April 11, 2020 at 4:59 pm

    Here are some countervailing facts about PZP. Turns out, PZP is neither humane nor harmless.

    1. PZP, a pesticide-sterilant, was registered without toxicity-testing: The esteemed animal-advocacy organization Friends of Animals has successfully challenged the legality of PZP’s registration on this basis.

    2. How It works: Behaving like a perverted vaccine, PZP tricks the immune system into producing antibodies that cause ovarian dystrophy, autoimmune oophoritis, ovarian cysts, and premature ovarian failure. [Kaur & Prabha (2014); Curtis et al. (2007); Mahi-Brown et al. (1988); Nettles (1997); Rhim et al. (1992); Sehgal et al. (1989); and Stoops et al. (2006).]

    3. Out-of-season births: Ransom, Hobbs, and Bruemmer (2013) conducted a longitudinal study of 3 wild-horse herds currently contracepted with PZP. They found that foaling was occurring nearly year-round rather than pulsing normally in Spring. Nettles (1997), too, had reported unusually-late foaling-dates where PZP was in use.

    4. Slow return to fertility, if ever: Ransom et al. also found that, after stopping PZP, it takes, on average, more than a year per each year-of-treatment before mares regain fertility. PZP’s manufacturer admitted it could take up to 8 years after just 3 consecutive treatments. Knight & Rubenstein (2014) found that administration of the first dose before puberty sometimes triggered sterility.

    5. Concern that PZP selects for weak immunity (Gray & Cameron, 2010): PZP works best — meaning, it sterilizes faster — in mares whose immune-function is strong. Conversely, PZP may not work at all in mares whose immune-function is weak. Thus, over time, a PZP-treated herd becomes populated with horses with weak immunity, making them more susceptible to disease.

    6. Dubious “benefit” of increased longevity: Exceptionally-long life is an ironic effect of PZP. The manufacturer of PZP actually boasted about mares living 50 percent longer, as if that were a good thing. However, other scientists (Gray & Cameron, 2010; Knight & Rubenstein, 2014) pointed out that ultra-elderly mares continue to consume resources while no longer contributing to the gene-pool. It is detrimental to the genetic viability of a size-restricted population to carry sterile herd-members way-beyond their normal life-span. Further, while PZP may reduce the number of foals, it enables adult horses to live longer. So overall, it’s a wash — the one cancels out the other.

    7. Hazardous, especially to women-darters: EPA’s Pesticide Fact Sheet on PZP advises that Personal Protective Equipment (PPE) requirements include long sleeved shirt and long pants, gloves, and shoes plus socks to mitigate occupational exposure. But often, darters have been observed not using PPE. They have been lulled into a false sense of safety by the manufacturer, who claimed PZP is “so safe it is boring.” Independent research shows otherwise — that PZP is a powerful hormone-disruptor.

    • April 18, 2020 at 9:30 am

      Thanks so much, Marybeth, for your brilliant and caring research to get at the greater truth concering PZP and for caring enough to share, to spread the light. The horses and burros are depending on our so doing. Happy Earth Day!

  • April 18, 2020 at 4:35 am

    Georgia, Marybeth, Craig…y’all are SPOT ON!
    We all know the plight, decimation of our “Wild Equine Treasures IS (always has been & will continue 2 be) plagued by a “follow the $$money” politicians, BLM & ranchers/landowners. There’s NO WAY OUT! Our magnificent “wild equines” continue to survive despite the endless/relentless armies of inhumane, powerful adversaries! We must ban PZP NOW…live as our equine sisters & brothers do…live each day as if it will be our last…& learn as if we will live forever…in service to our equine “partners”!

    • April 18, 2020 at 9:33 am

      So glad you are speaking out on this Dr. Rand! We must speak up for the wild horses and burros and demand the true implementation of the WFHBA. This is not supposed to be about subjecting the horses and burros to chemical sterilization or semi-sterilization and rendering the domesticated or semi-domesticated animals — rather, all the contrary! Have a good Earth Day and keep up the good fight for precious Life on Earth. Stay safe and well, Craig

  • July 31, 2020 at 3:50 pm

    It’s now proven that the precursor to horses were native to North America, something no human can claim. We need to get off their land. All of these so-called answers to the occupation by horses of their land only benefits humans, none of whom are native to North America. Our experiments are simply eradication attempts in the end. What can be done about that, about human greed?

  • August 23, 2020 at 9:02 am

    Thanks for your comment, Ellen, and so glad you understand and appreciate just how deeply justified and beneficial the horse is in North America as a native species and as a restorer of balance and biodiversity. Yes, the problem is one of human self-centeredness and blind tradition as well as selfishness and greed. We must make sacrifice of disproven, disharmonious norms and lifestyles that are killing the life of this beautiful planet Earth! Did you read my book yet: The Wild Horse Conspiracy? Also take note my recent note to many here where I live: Hope you are keeping safe and the horses with all these fires. See my recent article. it’s at https://www.horsetalk.co.nz/2020/08/15/america-wild-horse-elimination-govt-path-forward-plan/


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