Horse Health

PZP Study Raises Concerns for Use on Wild Horses

By Laurie Dixon of Horsetalk

Behavior Changes not Considered in Past Studies

Research indicates the long-term horse contraceptive, porcine zona pellucida (PZP), extends the breeding season in wild horses, raising concerns over the social consequences of the drug on herds.

PZP, which is derived from pig eggs, is increasingly being used in wild horse herds in the United States in a bid to slow down the growth in numbers.

Research published in the open-access journal, PLos ONE, reported on a study of wild horses living on Shackleford Banks, in North Carolina, covering four years before contraceptive management to eight years after contraceptive management with PZP.

The Princeton University researchers studied the foaling data, and found that since the contraception programme began in January 2000, foaling has occurred over a significantly broader range than it had before the programme.

“For a gregarious species such as the horse, the extension of reproductive cycling into the fall [autumn] months has important social consequences, including decreased group stability and the extension of male reproductive behaviour,” the researchers wrote.

“In addition, reproductive cycling into the fall months could have long-term effects on foal survivorship.

“Managers should consider these factors before enacting immunocontraceptive programmes in new populations. We suggest minor alterations to management strategies to help alleviate such unintended effects in new populations.”

The authors noted that while physiological effects of PZP had been well studied in horses, little was known about PZP’s effects on the scheduling of reproductive cycling.

They said recent behavioural research had suggested that horses receiving PZP extended the receptive breeding period into what is normally the non-breeding season. Their research into the Shackleford horses suggested this was the case.

Their study data centred around 65 births from 45 mares in the four years before PZP’s use by the National Park Service on the Shackleford horses, and 65 births from 45 mares following its use.

The researchers, Cassandra Nuñez, James Adelman and Daniel Rubenstein, from the university’s Department of Ecology and Evolutionary Biology, noted that immunocontraceptive management has become increasingly popular as culling programmes were seldom well-received by the general public.

In wild horse societies, the harem is the core social group, consisting of usually one, but sometimes two or three harem males, one or several females, and their offspring.

Harem males will sometimes fight to acquire mares from other groups, but stallions almost always retain their mares.

In temperate environments, food availability is lower during the fall and winter months and free-ranging horses will alter their activity to maximise food intake and reduce energy costs. Mares are typically not ovulating at this time and sexual behaviour in males is largely absent.

“On Shackleford Banks, increased reproductive behaviour in the post-breeding season by mares has resulted in increased male attentiveness,” the authors noted.

“Such behaviour (by males) has been shown to restrict the movement of females, thus reducing their grazing efficiency.

“The occurrence of this behaviour during a time of year when animals typically increase group spread to acquire adequate forage, represents a change in behaviour fundamental to the animals’ survival,” the researchers said.

“Offspring conceived during the post-breeding season are likely subject to decreased resource availability as lower quality forage can affect mares’ ability to produce sufficient milk.”

The researchers said breeding in the Shackleford herd normally occurred from March through August, with most births occurring in April and May.

“After contraception management, foaling occurred over a broader range of months than before contraception management,” they noted.

On average, current PZP recipients gave birth 3.36 months later than did pre-contraception mares.

Mares that had received PZP earlier in their lifetime, but not during the year of conception (prior recipients), gave birth 0.90 months later than pre-contraception mares on average.

Non-recipient mares that never received PZP themselves, but gave birth after the general population was managed with PZP, gave birth 1.01 months later than pre-contraception mares on average.

This translated into current PZP recipients giving birth 2.34 months later than non-recipient animals and 2.46 months later than prior recipients.

“This study provides the first evidence that mares treated with PZP can extend ovulatory cycling beyond the normal breeding season.

“This suggests that populations of wild ungulates can vary in their response to similar contraceptive treatment. Careful consideration of baseline population dynamics should be made prior to treatment in order to fully assess possible PZP effects.”

They continued: “Because feral horses are highly social, such changes can have cascading effects on other group members and throughout the population.

“Our research has shown that after contraception management, PZP recipients both attract and initiate more instances of reproductive behaviour and are more often the harem male’s nearest neighbour during the fall/winter, indicating that group spreads are reduced.

“Such changes represent an increase in energy expenditure and a potential decrease in nutrient intake during a time of year when sufficient energy reserves are at a premium.

“Moreover, early foal development in unmanaged populations typically occurs during the spring and summer when resources are plentiful. Offspring born in the fall/winter months face nutritional and thermoregulatory challenges not experienced by their counterparts born during the normal foaling season, potentially making developmental benchmarks difficult to achieve.”

They noted that such predictions are not consistent with data from Assateague Island, where a study of mares showed increased survival, only minimal physiological side effects, and no behavioural or demographic changes.

“In addition, foal survival does not differ between foals born in or out of the normal foaling season. However, on Shackleford Banks, recipient mares change groups more often, elicit and receive more instances of reproductive behaviour, and receive more harassment from harem males.

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67 replies »

  1. Such utter stupidity and thoughtlessness. Results of human intervention in the environment are everywhere around us. Must we exact our short sightedness on the wild horses as well. A hard rain’s a gonna fall.


  2. Number 1 mares are not simple to become in foal in the first place and also it is not easy for them to even produce alive foal, the use of PZP is utter nonsense stupidity, of course what do you expect of the Bureau of Lairs and murders……… It causes the mares to be heat more often which in turn causes Stallion wars, they are always fighting to get the mare, these people have no known brains in their heads, Wayne Pacelle has been shooting the mares for quite some time already with PZP, yes the man who is suppose to be helping animals, I would not contribute 1 penny to HSUS……………..What really erks me is they do not think about what the heck they are doing………….. What part of Let Nature Handle the Balance , shes pretty smart about those things …..All I can say is” but out” BLM and Wayne Pacelle……………..of HSUS, stick with what you know ??????????


  3. I found a reference on BLM website for NV that BLM could not have gone ahead with their PZP program WITHOUT approval by HSUS. I have sent an inquiry to HSUS on this. HSUS has also taken a stand that slaughter is okay as long as the animals are TRANSPORTED humanely – no statement on holding (no feeding, water) or the actual slaughter itself. HSUS needs to make their dealing with slaughter and BLM a bit more obvious.


  4. ISPMB(Internation Society for the Protection of Mustangs and Burros) President,
    Karen Sussman has had the unique opportunity to study and compare three different herds. One herd has suffered the damage from repeated round-ups and government meddling, while the other two herds have never experienced the trauma and consequences of a round-up–they have been left completely intact. The herds that have never been rounded up exhibit HEALTHY HERD BEHAVIOR, and that is one of Karen’s main concerns. HEALTHY HERD BEHAVIOR is the cornerstone of the preservation of these herds. The use of PZP is showing increased changes in herd behavior, and that is of PRIME CONCERN. In addition, where is there data to indicate that these herds have ever shown to be over-populated? There IS data showing that the round-ups actually CAUSE the birth rates to DOUBLE.


  5. And the shift in seasonal foaling rates is going to render the “Wild Horse and Burro”
    Handbook’s ‘gathers… after the peak of Foaling Season’ irrelevant; with PZP inoculations screwin’ everbody sideways, foaling season will be a year-round event.

    Not that foals have ever been a really strong concern in Round Up reasoning…



    [Federal Register: October 26, 2010 (Volume 75, Number 206)]
    [Page 65615-65618]
    From the Federal Register Online via GPO Access []


    Conditional Commitment for a Federal Loan Guarantee for Project
    Financing for Southwest Intertie Project–South

    AGENCY: U.S. Department of Energy, Loan Programs Office.

    ACTION: Record of decision.


    SUMMARY: The U.S. Department of Energy (DOE) has decided to offer Great
    Basin Transmission, LLC (Great Basin), a conditional commitment for a
    Federal loan guarantee for partial financing of the 235-mile southern
    portion of the Southwest Intertie Project (SWIP), a proposed 500-
    kilovolt (kV) transmission line that would extend from southern Nevada
    to southern Idaho. This Record of Decision (ROD) is based on the
    analysis in the Final Environmental Impact Statement for Project
    Financing for Southwest Intertie Project–South (SWIP South) (DOE/EIS-
    0443, January 2010) (DOE FEIS). The DOE FEIS consists of a cover sheet
    for the January 2010 adoption of the Bureau of Land Management (BLM)
    1993 Southwest Intertie Project Environmental Impact Statement and
    Proposed Plan Amendment (SWIP EIS) and the BLM 2008 Environmental
    Assessment for the Southwest Intertie Project Southern Portion NV-040-
    07-048 (SWIP South EA). This ROD also reflects minor modifications to
    the Great Basin proposal and new information developed since DOE issued
    its FEIS.
    DOE’s offer of a conditional commitment for a loan guarantee for
    SWIP South is authorized under Title XVII of the Energy Policy Act of
    2005, as amended by Section 406 of the American Recovery and
    Reinvestment Act of 2009 (Recovery Act). This conditional commitment to
    provide a Federal loan guarantee is contingent upon Great Basin
    satisfying all precedent funding obligations, and all other
    contractual, statutory, regulatory, environmental compliance, and other
    requirements specified by DOE. DOE has prepared this ROD in accordance
    with the Council on Environmental Quality regulations (40 CFR Parts
    1500-1508) for implementing the National Environmental Policy Act
    (NEPA), and DOE’s NEPA Implementing Procedures (10 CFR Part 1021).


  7. The use of PZP is an outrage. Messing with sex ratios is an outrage. Helicopter roundups and long term holding is an outrage. Blaming all the woes (that are suspect themseves) on Public Lands to a single entitity that is only 2%-3% of all large grazing animals is an outrage. Any cattle grazing on public lands is an outrage, even more so on wild horse designated lands.


  8. Thank You Louie for the herd study information , this proves without a doubt that Mother Nature does her job efficiently……… We need to Stop Wayne Pacelle and his PZP or PZP 22, these are all experimental Crap that they know nothing of the horrendous side effects what the hell is wrong with these no account as##$#@s , maybe they should test this crap out on themsevles first , then they can study how they are doing…………………. The BLM and HSUS needs to be tared and feather and run out of town…………………………………….I would like to know why HSUS has a horse in its LOGO, They certainly have never helped the MUSTANGS that I know of….. The only thing they do is harm them,,,,,,,,,,,,


    • I have to repeat myself – Who the heck takes an “experimental” drug and administers it across the board? This is obscene – what they heck were they, are they thinking?

      This is paramount to taking a cancer fighting “experiment”, and without knowing the side affects, dumping in to all our drinking water nation wide.


      • To your first question….the US federal government does (public health policies of the 40s, 50s and 60s) and Nazi Germany did.

        What bothers me is the role HSUS plays in this and their deafening silence of published science, etc and the obvious unplanned results on the well being of the wild equines. l also believe they are not using their own money for this. I believe it was a grant from a big foundation (Annenberg?).

        In the begining, I’m sure they thought it would help stop or at least slow down the roundups and help get a foot in the door with states and DOI (have some say so, if you will). They know now that they have a very rogue agency on their hands and the program has been twisted by the killers. I suspect that is why they don’t talk about it any more publicly.

        Anyone know if they are still funding or has the grant dried up?


      • Flagged again! Guess I should have used the term facisit Germany, instead of the big “N”. Oh well, live and learn.


  9. I am wondering , a a suit be filed against the BLM for Misrepresenting themselves? Misrepresentation , they say that they are doing these round ups for the good of the Mustangs, would be rather easy to challenge that, we all know there is plenty of proof document to prove that they dont……………. Therefore they are misrepresenting themselves, would that not be grounds for a total dismissal of all at the BLM?????



    BLM Nevada News
    Winnemucca District Office No. 09-01
    For Release: October 7, 2008
    Contact: Mark Struble, Acting Public Affairs Officer, (775) 885-6107
    BLM Announces Selection of New Field Office Managers in Winnemucca
    October marks the Bureau of Land Management’s Winnemucca Field Office reorganization as a District Office geographically divided into two regional field offices–the Black Rock Field Office and the Humboldt River Field Office–which will be located at the existing office on 5100 East Winnemucca Blvd. in Winnemucca. Newly named field managers are Dave Hays for the Black Rock Field Office and Bob Edwards for the Humboldt River Field Office. Rodger Bryan is the acting district manager.
    Black Rock Field Office – includes BLM managed public lands in the Black Rock-High Rock Emigrant Trails National Conservation Area on the west side of the District.
    Humboldt River Field Office – includes BLM managed public lands on the rest of the District.
    Earlier this year, the BLM Nevada State Office announced a state-wide reorganization to better serve public land users and meet increasing demands on public lands natural resources. BLM Nevada has realigned from a two-tier structure of a state office and field offices to a three-tier structure of state office, district offices and field offices. This reorganization is consistent with a Bureau-wide organization which was implemented to allow for decisions to be made closer to the resource and the resource user.
    At the district level there will no longer be Divisions of Renewable and Non-Renewable Resources, however those divisions will remain at the state level. Fire management, law enforcement, public affairs will be at the District level and serve the two field offices.
    For more information, please call (775) 623-1500.


  11. If I had to pick between PZP and keeping them on the range and incessant, cruel round ups and lifetime holding in corrals, I would choose PZP.


    • TJ Holmes said on her Spring Creek Basin blog today, under a pic of a long yearling nursing his mother…. mar

      … “What? You think this is wrong?” (name that commercial) The only side effect I’ve seen from the PZP-22 has been that the foals – Storm and Corona, daughter of Raven – continue to nurse because their mothers are not pregnant and their bodies don’t seem to kick in and tell them it’s time to wean the current foal. This seems to only strengthen their bonds, provide continued and additional nutrition to the growing youngsters and not affect the mares adversely. (Does Alpha look like she’s been adversely affected? 🙂 ) I’m not sure how much he’s getting. Alpha let him nurse for a couple of minutes, then walked off, and they both continued grazing. Gideon, deprived of one shade buddy, walked up the hill a bit to share shade with stepdaddy Butch. (Notice Luna, Gideon’s dam, in the upper left corner of this photo.)

      Spring Creek Basin is a small, 20,000 acre HMA near Disappointment Valley in SW Colorado, and because water is very scarce and the area is not very forgiving she has sided for the option of PZP and would like to be allowed to dart the one year kind and avoid the roundups. She might need support to get this through BLM. I do not blame her. In a better world she would be able to ask for a larger land access for the horses. If the herd stays under 100 (they are around 80?) it may seem to be genetically poor but these horses are lovely and healthy and so far so good. When the herd is upwards of 120+ horses the resources are thinner and she can see the difference. So, she has made a decision based on all her available knowledge, observation and choice. I hope BLM will allow the horses to stay. There is a roundup scheduled next summer. mar


  12. Is there a concensus among hands-on advocates on the approprate way to manage herd side on public lands? Considering the fact that they are limited in grazing range just by the fact that they coexist with lots of other creatures including humans, they obviously cannot be left to reproduce at will endlessly, correct? Even if we could wiggle our noses and make BLM go away, there must be some sort of herd size management, right?


    • BLM has stepped in to remove horses during droughts and fires. This ability to control by removal then became an option for population control. Louis is right about Self Sustaining Herds and Sandra emphasizes the adoption of horses was and should only be a last resort, also. Not a business they have either nearly abandoned or played up to the hilt like mustang makeover.

      Craig says they will self regulate when left alone. Pryor horses seem to have been doing that very well before the hunters and BLM came along and pressured them. They had been about 230 horses according to witnesses for decades. Larger herds on larger HMAs may pose different challenges but what the 71 Act and subsequent program never studied was how the horses do Move between HMAs. Populations swell and recede with the migrational movement of bands.

      Best case scenario; stop the roundups and allow the study to be done. Have other
      outside scientists work with the study group and compare notes as it is done. Get back to science.
      Stop the roundups. mar


    • Elaine, Just one of many good answers – stop killing the predators.

      But that will not be done as long as lovestock is grazed on the same land, which leads to another good answer – stop welfare ranching entirely on Public Lands, which would free up almost 1 BILLION dollars a year in tax revenue, which leads to all sorts of other good answers.

      Roundups are what cause over breeding – then more roundups – just an infinite scam for tax money for the current BLM program, Cattoor and Cook, warehousing, et al. Salazoo will open up a gold mine of tax dollars for these groups.

      Google PZP in deer – you’ll find much information and I was astonished about the reports that over hunting and rounding up non-native deer has been abandoned due to increasing the overpopulation from over breeding (compensatory breeding) – wow – who would have thunk it? But Craig Downer and Ginger Kathrens among other well respected knowledgable people have been saying this for years now.

      So why do they keep doing all those helicopter roundups with buffalo and wild horses (both native I might add) and just selective PZP (even if they PZP every mare they round-up they never get all the horses out of every HMA and the PZP is only good for 2 years and the next roundup will be 5 years or more)? Hum? Could it be – greed?

      Anyone recall where that report of botched BLM numbers was – enough shanaigans as evidenced by the numbers on the various BLM websites – yes by BLM’s own numbers! Horses counts up to 300 and 400% increases in 2 or 3 years, while other herd numbers decrease, coincidentialy, by the same percentage WITHOUT roundups in neighboring HMAs (and one clue should be that increase is physically impossible by breeding) – then swoosh, that one is back up 300% in a couple of years to justify yet another roundup? Elaine, this one will blow your socks off it’s so crazy it seems impossible but it is taken right from the BLM pages. BLM is insane, at least drunk, on power and greed I say. Ask over at The Texas Mustang Project – I think that is where I first got the link to that information.

      Elaine – much research to do, please stay with it.


      • “lovestock” – wow – that is certainaly a typo (among probably severlaothers)! I have good days and bad.


  13. Elaine, there is a great deal of good information and data from ISPMB. This is one of the oldest and most respected Wild Horse and Burro protection organizations in the country. Wild Horse Annie was its first president. Go to their website or contact Karen Sussman. She is a wealth of information–much more than can be posted on the blog:


  14. Karen Sussman has been on several radio programs and she has a tremendous amount of experience and knowledge–much more than is shown on the website. You could contact her.


  15. Craig Downer is another wonderful source of information and he would be the first to tell us that the goal we are after is SELF-SUSTAINING HERDS. That is a goal that has been achieved in some herds. In GOOD wildlife management, there is a wonderful balance. Our job is to see to it that we help, not hinder.


  16. We have not even discussed PZP-22..the drug they are now using on ALL mares that are returned, and since they are rounding up all horses on HMAs..WHAT does that say, are you not reading the EAs and the amendments to the EAs? It is PZP-22, and anyone who supports a drug that some scientists say can permantly sterlize aught to be shot themselves..this drug has not been approved by anyone in cluding disneyland-except aparently the Inhumane society which is nowdays a lackadasical frount for the BLM…to allow a drug that is dubious and untried is at best-the works of Frankenstein..I read quite sometime ago(USGS) about some trial being done and the questions about permanent sterility..there is no going back on this..its what the mares are now getting in the rate. DONOT sell out the wild horses because you cannot stand to watch the damn roundups..stop the roundups!!!


    • Another reason why, as we are still seeing our newly captured horses being processed; gelded and shot up with experimental PZP-22, that we need to intercede and adopt all we can to prevent this killing off of all future offspring. The horses are Not Overpopulated and the damage is getting worse. Stop the roundups or adopt!! But save the wild ones NOW! mar


    • At some point during this roundup season, BLM did a U-Turn and inserted PZP-22 instead of the 1 year variety..There must be an “inter-agency Memo” that went out across all offices- we need to get this memo with a FOIA..I first caught on, when they added an amendment to the Warm Springs EA AFTER comments had already been went from PZP of the mares being returned PZP-22 OR ALTERNATIVE methods of birth control..and anytime the BLM uses that usually invoves some drastic methodology..the last time was the killing of all healthy wild horses deemed excess..Warm Springs roundup is this weekend in Burns Oregon, and “we” will be there..could it be they are scheduling this “media” tour of LTH facilities at the same time for a we have seen before???? To distract people away?? they are filling the 2 day slots on Nov 5 & 6 with their volunteers…only by “fussing” did we get an extra day so we could go..initially one day and all of “us” were excluded.. I was going to contact my senator Ron Wyden to intervene on our behalf.


  17. They have been using PZP on deer also – just picked this one article arbitrarily from Googling PZP in deer – suggest seing a few of these articles tht show up:

    There seems to be one error where they do talk about horses not cycling with the PZP – I think more current observation is that is not true.


  18. This is about non-native deer populaition problems but interesting paralells to our discusion here today – especialy interesting is this part:

    “…Rate of Removal. On page 2, HSUS states that “species can reproduce more quickly at low densities” thus outpacing removal rates…” Isn’t that what I have been saying about horses – remove some and they will over breed?

    Click to access Point%20reyes.pdf

    In this case they are treating the non-native deer as intruding on native deer and elk habitats. In our case we are dealing with non-native cattle and sheep intruding into native wild horse habitats.


    • I guess, just to expound on this.. and going back to ‘Mother Nature’…
      ANY and ALL wild species have an innate repoduction ‘law’.. When the numbers of ‘them’ decline.
      Species recognize this NOT because anyone ‘told’ them but because it’s just plain and simple ‘Mother Nature’.
      When any species population starts to dwindle, weather it be because of ’round up’s’ or because a natural act has taken place; a species WILL try, for it’s own SURVIVAL to ‘make more’ to ensure it’s longevity and SURVIVAL.
      The act of round up’s does this alone AND add the act of using
      PZP, so now we have TWO HUGE factors in that our Mustangs are trying with everything they’ve GOT to ensure their survival.
      So, with BLM trying to STOP reporduction, they’ve only pushed it into ‘OVERDRIVE’, so to speak… A fact of ‘life’ and a simple ‘law’ of nature.
      This is biology and zoology at it’s simplest…
      Yep, we’ve got some REAL genius’ workin’ for us @ BLM and HSUS..


      • Hi Joey – great post – thank you!

        I think they ARE genius – they just act stupid, or intenionally hire stupid PR people (and an occasional Oscar worthy performance) on camera and in the press to cover up their scam – I think they have known this for at least 40 years and have capitalized on it to the tune of – just for Cattoor alone 1.2 MILLION dollars a year! That is documented from Federal papers, and is here on R.T.s web site somewhere (can’t keep track).

        Dumb like a fox?


      • Joey, by the way – is there also a ‘law’ in nature that turns off breeding when numbers are too large? Or is that to starvation and the like?


    • Oops.. I dunno if I ‘replied’ underneath our conversation, Rox.. But.. Here goes!
      To hit the ‘other end’ of the spectrum.. It goes back to Mother Nature. ‘Feast or Famine’, maybe?
      When forage and great conditions exist for any species, yes there is always a chance for overpopulation. But again, ‘we’ have interveined TOO much.
      There aren’t the natural predators needed because ‘we’ve’ managed to take them out of the equation.
      When there is a ‘feast’ of forage for our Wild Ones, there should also be a feast for the preadators. Sounds harsh, but Mother Nature does what she needs to do for ALL her creatures.
      There are times too, when herds will control their own populations such as, if a foal is born with a ‘defect’ of sorts. Momma won’t take care of it, a herd Stallion might step in and kill it… Ewww.. No, not a nice picture but both are ways that Mother Nature takes care of her own.
      You can’t have a member of the herd that may hinder it’s ability to ‘keep moving’ or that won’t be a good genetic ‘mix’.
      And, this has ALWAYS amazed me… A Stud won’t breed with EVERY mare that is ‘ready’. It’s Natural Selection at it’s best, if left alone. He’s going to breed the strongest, healthiest mares.
      (This just isn’t for horses, it’s for ALL species. I just used our favorite here!)
      So, we try to stop them from having offspring, but only makes it worse for them.
      We take away an intregral part of the ‘food chain’ and we do have over population. It’s all a Catch-22 and one that man made at the expense of our Wild Life.
      So, Yes, we DO need to ‘manage’, but not so ‘hands on’.
      And, definately.. Dumb, just like a Fox! ;O)


      • Joey, thank you.

        I just wondered if they had any innate way to slow down breeding before water or forage would become scarse – if they sensed that. That the Pryors maintained about 250 for eons before BLM came along is testament to something – just don’t know what.

        I personally have no problem with the gruesomenss of natures ways – everything you have mentioned – and especially the predator. And I would add starvation, but this is not representative of most advocates I would say – pretty sure I am on the fringe on this one issue. However that is a natural way of weeding out the less strong among them and is a matter of fact for many animal populations on a regular basis. These are wild animals after all.

        Yes, BLM has messed with mother nature. I hope the damage is not irreversable and the damage makers are reversable – or booted out of the hen house all together.

        I thought the latest Cloud installment showed other amazing traits – that Cloud sent one of his mares off with another stallion, after a few other stallions “appllied” for the job, then after she was impregnated Cloud went and fetched her back – AWESOME!


      • Well SHOOT, Rox! For some reason I couldn’t reply underneath your response, but under mine?
        Here’s me w/my Western State College biology minor.. (ummm, and what I retained with my ‘beerology’ major?) hahaha! ;o)
        K, here goes…
        No wild species ‘knows’ when there will be a famine or feast. This process actually takes years to ‘play out’. Let’s just say drought for an example..
        So for a few seasons the horses DON’T have lush green pastures to munch on consistantly. But this happens over a few breeding seasons. They have learned.. (but still innately..) that the food is limited. So is their water. It is there, just not in abundance like say, five years pryor.. (Just throwing that out there…)
        It’s this INNATE behavior that is vital to survival. One that isn’t taught. It’s just ‘known’. Going back to mating the strongest and healthiest mares. Our ‘boy’ isn’t going to mate with his mare this particular season because she IS strong and he wants to keep her that way. In fact, it’s doubtful there will be any foals for these drought periods and for possibly a few AFTER that. Because Mother Nature tells ‘our boy’ that he’d better take care of who he’s got. His strong mares, his three two to three year old offspring. They are still strong and healthy too.
        Mother Nature also reminds ALL of the ‘boys’ that now is not a good time for trying to add to their bands. More to watch over, find substansial food and water for and of course challenges and fights over mares. That only uses up precious resources, energy AND more need for forage that isn’t there.
        The saying, “only the strong survive’; not just lyrics to songs, etc.. It’s the REAL deal!
        When these animals make it on the very barest of minimums, but STILL MAKE IT.. That’s your ‘strong’.
        IF (big if), we still had our predators, they would take the very young, old and weakest members. Again.. not such a nice picture but it is what it is. And really, isn’t it because of THIS.. being that they are strong and wild and free, why we so drawn to them and their very spirit?
        Let’s look at Cloud.. Before he was ‘here’, his sire and dam had already ‘chosen’ him. Of course they didn’t know he would be a ‘he’, but who knows.. genetics was obviously on their side and yep, so was Mother Nature! Fifteen years later, that’s a LONG time for a wild anything.. Cloud is STILL here.. And NOT because it was luck or a ‘fluke’. He was chosen.. INNATELY.. We could go the other route too, that if ‘he’ would have been a ‘she’. My money is on the fact that ‘she’ would have been one helluva lead mare!
        So, I hope I didn’t bore you guys, have too many mis-spellings or jumped around too much!
        It’s just sort of simple when you do look at the ‘laws’ of nature. If left to itself, to ‘police’ itself, I guess.. It’s a pretty cool thing to behold. No one seems willing to watch and learn anymore. Takes too much time? I don’t know. I do know it’s a shame because it’s a lose/lose for everyone. We can’t get back what is already PZP’ed or gelded. That, we KNOW, IS their ‘plan’. :o(
        Remember the commercial.. ‘It’s not nice to fool Mother Nature’?


      • Well said, Joey. That time they need to allow the herds to settle is what both Craig Downer and Karen Sussman elude to. It is where many herds were before BLM tampering. Making their territory smaller and smaller created the need for the revolving roundups and removals in order to be in ever smaller and smaller places and the horses have done all they could to adjust. They are very fine and strong as we see in photos from every roundup. Now their lands are hacked up and they are under populated on many HMAs. The cattle and sheep making up the difference and artificially squeezing the herds further. The problems BLM describes are just not there in these years they are taking the most horses at the end of their fight, their populations just dropping off to nothing or being entirely zeroed out officially. This is so contrary to the ’71 Act. mar


      • Hey Mar! Thank you! 🙂

        Yep, so now after all the roundups, the herd Stallions are in a ‘tizzy’… Trying to form new families and make babies to get their population thriving again. It’s how they are ‘hard wired’. But, I think we all know too, that even in this ‘overdrive’ state, there’s no way these animals will even come close to 20% in 4 years, like the BLM says they reproduce.
        Especially AFTER a roundup. These animals are stressed to the MAX.. They don’t have the family dynamics they had. It’s like a corporation trying to rebuild. It takes YEARS to ‘make’ a new family in the first place.. Then add in all the stressors. And, since the BLM sees to it that most of the genetically viable Studs & Mares were taken off to Horse Prison. Now, they also have to deal with.. OK.. I’m not the BEST one for this job, but I’m the ONLY one for this job.
        It’s just such a waste. A waste of such an intelligent being, waste of time and money. I would think, that if they were SO concerned with the Mustangs that they would take a step or five back and just watch for a while. But.. then their pockets wouldn’t be full, now would they.
        It’s hard enough when they have to fight each day to survive elements, finding food and taking care of their own but to have the added stress now of trying to become ‘whole’ again after the BLM basically decimates their whole ‘world’.


      • Joey & Mar –

        This string of posts warrants on this subject should be in an Article – you two should put your biology minds together and write this and have R.T. post it. This is the kind of stuff – biology/nature 101 – that we all need to know well enoough to educate other people.

        And, this brings me to mind of something I posted a long time ago and bears repeating here in this discussion – selecting horses to go for adoption vs Mother Natures plan of survival of the fittest.

        Tell me how BLM selects horses to return to the range and the ones they selelct to keep for adoption? This is my take – either they are slecting the fittest to return to the range as Mother Nautre would – but then – that means they are keeping the crapiest horses to go up for adoption? No wonder the adoption program does not work. On the other side of that coin if they are selecting the best to go for adoption they are deliberalty sabotaging the future strength of the herd by returning the least fittest.

        Let’s face it, there is absolutely nothing good about any BLM “posturing” (I can’t say reasoning or logic – just does not fit) except for filling someones pockets with our tax dollars.


      • Whoa! Roxy! There are horses returned in Utah who are picked for their best qualities but not all of them are returned. And few of our wild horses could qualify as ‘crapiest’!
        Believe me, the vast majority of the wild ones are amazing horses. I got to see hundreds this Spring on the road in HMAs and in facilities in Nevada. Our wild horses are magnificent. What they used to do was not take the older horses and concentrated on the younger. Now they are taking the older and the younger, gutting the families and also trying to head off future breeding horses by taking all the young. We need to adopt foals and stallions and all we can. I say get all the weanlings from BLM now. They have been treated like crap by Contractors as they are not counted and they bring no money. But to BLM the young horses represent the future and BLM Does Not Want Wild Horses To Have a Future!!! Every thing I write and think right now just brings me back to same conclusion; get the horses off the ranges before gelding and PZP and adopt/buy them. Get all the foals. Save the future. Too many foals died this year. We Do Not Know How Many!!! Hundreds, before the year is out, my guess.

        If you think someone else can solve these problems all I can say is; No, these problems are ours and we must be the ones to follow through, make the sacrifices and stand our ground and Advance Against BLM!! mar


      • They are either doing one of 3 things:

        1. They are not descriminating at all – just picking a few to return and a few to attempt to adopt – no selection process or evaluation of the horses – thus messing with Mother Natures survival of the fittist.

        2. They are picking the best for adopting, thus returning the “not the best” to the range – thus messing with Mother Natures survival of the fittest.

        3. They are picking the best to return to the range – great for the horses wild survival and in line with Mother Nature, but not so great for adoptors or the chances of the horse not becoming 3 strikes and/or living past 10 years old to become sale authority horses, warehoused at our expense, sold out in lots going off in trailers to who knows where to make room for yet more rounded up to be warehoused horses.

        No answers or solutions to my post – just pointing out another BLM mess of brain matter. I’m certainly not proposing stopping anyone from rescueing any and/or all 40,000 in warehousing or rescuing the horses immedialty upon roundup – figure out a way and just do it.

        But the roundups continue on.


  19. This is extremely stupid, & completely unnecessary!! WHY do people feel the “need” to play “God”!!?? Wild horses do NOT need PZP !! They have natural predators & weather, & many other “natural” built-in birth control methods. This is screwing up their normal, instinctive, biological breeding season. Man’s stupidity & ignorance never ceases to amaze me, & not in good ways!! I do NOT believe the HSUS is “ok” with horse slaughter, I’d like to know where some of these people are getting this info.?? They must be brainwashed by all the lies the “opposition” is telling everyone!! The “opposition” is always looking for someone to take the blame!! So, while everyone argues back & forth, wild horses continue to suffer, be given drugs/pig hormones to “control” their breeding, removed from freedom & their homes, separated from their families, forcefully & inhumanely gelded, brutally driven to injury, &, for far too many, to a tragic death!!!! And, apparently, no one can stop the BLM!!??


    • Well said.

      Iwould pint out that they do not have natural predators at this time – as BLM as seent othat and has killed them also.

      Get the dang cattle and sheep out and then there is no need to kill off predators and then we WILL see self sustaining herds of wild horses.

      Energy and mining COULD be done correctly and COULD live within the wildness that we all want maintained on the public lands – gut the welfare ranching progam – give that 1 Billion (less a little to manage the wilderness) a year to energy to do it right (like in my opinion put solar on every roof in the USA instead of building new solar farms – everyone buy an electric car for daily use – that would eliminate how much need for CNG, oil, coal? Let the energy companies own the panels and/or the power they produce – I don’t mind paying what I’m now paying – just to stop all this insanity).


      • Rox, not true… they are out there and they do have an effect on herds in many places.
        They are also hunted. But the mountain lion (and possible wolves for the first time in nearly a century), have always been a factor. Lions hunt foals here in CO and in Wyoming and at Pryor despite what others say. I think Sandra has implied lions hunt foals in Oregon, also. They have in CA and NV traditionally.

        Remember BLM does not count or acknowledge foals until they can be weaned. This year was a deadly one for foals although Laura Leigh’s intentions had been to give extra support and attention to them in order to try to help more survive this pivotal summer in the lives of our wild ones. She also wanted to disprove the horses are reproducing at 20% growth. Next year there will be fewer foals, fewer bands and more zeroed out HMAs. Many less wild horses. We need to activate our numbers and get this stopped in DC. We must support the suits also and remember to ask the appropriations committee and our reps to stop funding BLM and the roundups and PZP experimental use and the field operations on wild ones to sterilize them. mar


      • I go by what Ginger Kathrens says, of course her main scope is the Pryors, and she says there are not enough predators at this time because cattle and sheep ranchers cause BLM and FS to kill off the mountain lions because they are predators to their livestock.

        If there were enough predators there would seemingly be no need for roundups at all – totally wild self management.

        I read on one of their websites that we taxpayers even pay the ranchers for scavanged dead livestock taken by predators – what a tragic mess on every level!


  20. We talk about the BLM not using science but I believe it is imperative that advocates are versed on science pertaining to our wild horses.
    I just watched this 77 minute program that is a presentation on wild horses and birth control by Jay Kirkpatrick, developer of PZP. It covers much information and I challenge all here to watch it.


  21. Awesome Barb thank you very much for the link, I watched it, it was very informative….. But it also proves without a shadow of a doubt that there in fact is no i repeat overpopulation and it must be administered properly and we were listening to its inventor also……. I had a little problem with my computer during viewing it so i did miss parts of the presentation…………….. So now knowing that there is a solution according to the video, why are the BLM continually rounding up wild mustangs needlessly in in fact this control is available ??????????????//


    • Arlene, I posted NYT article about this program above and it includes Ginger Kathrens perspective.

      It apparently works well in a sancturay because the horses are usually more docile and it can be administered correctly. The problem in the wild is you have to gather the horses to administer it, it is only good for 2 years and gathers are usually scheduled every 5 years.

      And the timing is bad – it needs to be applied in winter, exaclty when it is the most dangerous to do a stampede and impossible (or too slow and costly) to do bait traps or darting due to snow and weather. Any other time of application and we now have the evidence that it skews the fouling season.

      The rest here are my arse ramblings – skip if you want – gathers, PZP, sterilization, private sancturaries are all nonsense anyway – the real solution is to leave the horses alone on their land – remove the livestock and retain the predators, bait trap only when scientificaly necessary, create Craig Downers sustainable pods so that real science can be gleened, do a better adoption program and create a Society/Club that gets people intimate with the horses. At least that is my montra and the only thing that makes sense to me.

      Some are asking “how can I adopt or sponsor saving an entire family band” – why not sponsor them to be kept in the western wild Public Lands?

      I have recenlty come to ponder whether our immediate heart string pulls to save as many as possible through private sancturaries is not only not stopping BLM, but may be aiding the enemy by creating a solution for BLM of what to do with the horses that are gathered. These roundups make money for BLM employees, Cattoor and Cook, for holding facilities, and make money for cattle grazers because now they can put more cattle on – all paid for with our tax dollars.

      Create something like Audubon or the Parks stamp and badge program to get people out there and documenting the individual horses, bands and herds and wilderness and all the living things and beauty there – sustained eco tourism = sustainable herds.

      Create a competion between people to document the horses and the land – like Field of Dreams (or Boy and Girl Scouts) – build it (competition) and they will come. Herd Watch is a first step. Then people, groups, high schools, colleges, associations could sponsor herds and raise money for them to be kept wild on Public Lands – not to mention what could be done with that 1 billion a year of our tax dollars currenlty keeping welfare ranching alive – that could be used to force energy and mining to do a better job and create eco tourism that will create jobs? Even for the helicopters – people pay millions of dollars a year to go on helilcopter excursions all over the world. And on education that these are a NATIVE species.


      • There are two forms of PZP and the one the Island pnies recieve, the original, is a one year contraceptive. Even matt wants to use this. It is applied by dart. It can be problematic and in larger herds apparently BLM did not even want to consider it. PZP-22 is experimental and needs to be stopped in its tracks. Horses need to be captured for this because it is placed beneath the skin. Fillies should never be given this and even older mares who have foaled previously have been known not to conceive for more than two years after, if ever again. mar


      • Roxy, the problem with that idea..which is by the way..a good one..Is that the BLM legally stands in the way of us sponsering the horses on the public lands..That is exactly what is happening with our taxdollars now..we are paying to leave the horses on the land..The BLM does not want them on the land, and they remove them anyway..these sanctuarys are to preserve the genetics and the wild instincts..It has become apparent they have decided to permentantly sterilize the what appears to be a wild herd on a HMA-is nothing more than a non reproducing LTH facility..We do not need any PZP..the horses are not over populated..they are fat and sassy and in balance with nature..BLM keeps shrinking the available land on the HMAs..there is no shortage of anything..except that caused by their constant tinkering-and their license to steal.


      • Sandra, I was identifying possible solutions – thinking outside the box of how to stop roundups – not a narrative of what exists now (I do plenty of that also here and there).

        Laws, programs, departments, rules and regulations come and go and get amended -What is popular and trendy for people to spend their time on comes and goes also and affects those laws, programs, departments, etc. How do we get that done for the benefit of the wild horses to be let alone on our Public Lands and save citizen tax dollars while doing it?

        It is complex, our heart strings want to rescue them all – and great if one does rescue – go for it! But then how does that stop the roundups and warehousing and sale authority? In our desparation we even have citizens who will pay for PZP dart application out of their own pockets just to temprorarily ward off a roundup of the herd that they feel compelled to save – perhaps they even intend to do this for several years? I understand that urgency, that passion, that love and can’t deny them – I feel that desparation also every time the helicopters take to the air. But agian, how does that stop teh bigger picture of the “roundup industry” – and that is what this is an “industry”. And I hope beyond hope that every lawsuit will someway stop this insanity in its tracks – maybe the next one will – I hope beyond hope that Congress will do something meaningful that will work (what has happened with Mary Landrieu or ROAM anyway? At least ROAM would wipe out the sale authority).

        Maybe we could/should be capitlaizing on the Obama “Get out” campaign – piggy back wild horse eco tourism projects and fund raisers onto that. At my partiuclar juncture in my life I seem to only be an idea person, I no longer have the physcial or monetary abiltiy to do more, but I have lots of experieince and have always been used by my employers on improvement and reorganizaiton teams – so I guess that is my only contribution other than hitting YouTube and the News blogs for possible additional public involvement – and who knows, perhaps there is someone or some group out there, or even someone here who does not even realize it yet that just needs to be tapped that will be able to put it all together and pull it all off..


    • Plus, I must add regarding BLM, Cattoor, Cook and LTH – the more horses that are removed the more the horses over breed, then more horses to gather, the more the horses over breed, then more horses to gather, tthen more the horses overbreed …infinitum!

      I have recenlty found this is common knowledge in other wild animals that are managed – HSUS has documented this for years. Plug ‘PZP in deer’ into Google and start reading – some amazing info. Reyes Point (or is it Point Reyes?) in California with the White Deer especially interesting – these non-native deer were released from the zoo a few years back and are invasive and destructive to the natural ecosystem – they think they can be eliminated by 2025 with PZP in a humane way. And other ‘non-native’ deer situations where they have overpopulated native deer and elk ranges all across the country. Gathering or over hunting just increases the breeding above normal levels.



    Release Date: 10/07/10
    Contacts: Lisa Ross , 775-623-1541 ,

    BLM Seeks Public Input on Proposed Wild Horse Gather in Augusta Mountains Area

    Winnemucca, Nev. – The Bureau of Land Management (BLM) Winnemucca District, Humboldt River Field Office has prepared a preliminary environmental assessment (EA) proposing to gather about 344 wild horses from in and around the Augusta Mountains Herd Management Area (HMA). The BLM plans to gather and remove about 50 excess wild horses that have established home ranges well outside the HMA in the adjoining Fish Creek Mountains. All horses gathered within the HMA will be returned back to the HMA. The BLM would appreciate receiving substantive comments on the preliminary EA by November 5, 2010.

    The established appropriate management level (AML) for wild horse population within the Augusta Mountains HMA is 185 to 308. The BLM estimates there are currently 294 wild horses in the HMA. The BLM proposes to gather the wild horses in the HMA and vaccinate all of the mares with the PZP-22 (Porcine Zona Pellucida) fertility control drug. The goal is to slow population growth and maintain population size within the AML, and extend the time before a gather to remove excess wild horses would be needed.

    “Keeping the herd population in balance with the available forage and water helps keep these wild horses healthy,” said Mike Truden, Humboldt River Field Office manager. “It is the BLM’s responsibility to prevent deterioration of the rangelands, achieve and maintain a thriving natural ecological balance, and achieve and maintain healthy, viable wild horse populations.”

    The Augusta Mountains HMA is located in Churchill, Lander and Pershing counties, about 75 miles southeast of Winnemucca, Nevada. The proposed gather is tentatively scheduled to begin in January 2011.

    The document may be reviewed online at Printed copies are available upon request from the BLM Winnemucca District Office. Questions and written comments should be directed to: Mike Truden, Field Manager, Humboldt River Field Office, BLM Winnemucca District, 5100 E. Winnemucca Blvd., Winnemucca, NV 89445-2921. Comments may also be submitted by email to Email messages should include “Augusta Mountains Gather Plan (Fox)” in the subject line. Public comments submitted for this project, including names and addresses of commentors will be available for public review at the WDO during regular business hours 7:30 a.m. to 4:30 p.m., Monday through Friday, except federal holidays.


    The established appropriate management level (AML) for wild horse population within the Augusta Mountains HMA is 185 to 308. The BLM estimates there are currently 294 wild horses in the HMA. The BLM proposes to gather the wild horses in the HMA and vaccinate all of the mares with the PZP-22 (Porcine Zona Pellucida) fertility control drug.


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