Sunday, December 26, 2010

TJ Holmes Interview: Why PZP?

****Review from Part I--After TJ experienced her first Mustang roundup--helicopters, mistaken horses, and a mare placed in the stallion pen and almost killed--she became passionate about documenting the Spring Creek herd and finding a better way to bring the horses in--such as baiting with minerals--and, ultimately, controlling their numbers in a humane way, with PZP darting. The next segment concentrates on the use of PZP.****

Interview with TJ Holmes (continued from this first segment)

You’ve said that you’d advocate the use of PZP to control the growth of Mustang herds, can you tell me why you’ve come to that decision?

I am absolutely an advocate of fertility control in wild horse herds, with the caveat that it be used as it is meant to be used - in the best interest of the horses. I am absolutely against permanent sterilization of wild horse herds - we are trying to protect them, not "extirpate" them. Gelding stallions and SpayVac and GonaCon fall into the permanent sterility category, although PZP can cause sterility if used several years consecutively.

That said, I am not against mares of at least 15, that have had many surviving foals (that have not been removed!), being allowed to stop reproducing - become sterile. We've had at least two old mares in the basin since I began my documentation that have had foals right up to the year they died, leaving them in very poor condition and leaving their foals orphans. Nature, but not very humane if we can do something about it.

We also had a mare die in foal birth that had healed from a broken pelvis. She was perfectly healthy, but having that foal killed her - and the foal. She would have been a perfect candidate for PZP. In a herd our size, she likely would have eventually been removed, but until then? She and her two stallions (yep, that's right) were very close. I'm going to anthropomorphize here, but I believe the dominant stallion still mourns her - he hasn't regained the "spirit" I previously knew in him.

I've studied PZP research and talked with numerous people about it - people in the private sector as well as employed by government agencies such as the National Park Service (think the East Coast horses; PZP has been used for 23 years at Assateague Island National Seashore), the U.S. Forest Service (a program just started with the Carson National Forest wild horses, our southern neighbors in northern New Mexico) and BLM. This summer, I went through PZP and darting training at the Science and Conservation Center in Billings, Mont., with Dr. Jay Kirkpatrick, one of the (if not the) foremost PZP experts in the world.

Something else to know: PZP is used on a wide variety of species around the world - in zoos, game preserves, private sanctuaries. In wild horses at least, its use is regulated by the Humane Society of the United States, which is currently studying PZP-22 in mares of the Sand Wash Basin, Colo., and Cedar Mountains, Utah, herds. PZP-22 is a time-release pellet with a hoped-for efficacy of 22 months - two gestation periods. But that hasn't proved true in reality, and they're seeing that the timing of application is pretty narrow. PZP-22 given to Sand Wash Basin mares in October 2008 was not nearly as effective as PZP-22 given to Cedar Mountains mares in December.

Currently, the BLM looks at its Wild Horse & Burro Program from the end result, "excess" horses, however, I feel the BLM should look at the appropriate place, the beginning stage, which is reproduction.

When the NPS started looking at a management plan for its wild horses more than two decades ago, that's exactly what it did. Fifteen years after the plan was put into full management on Assateague, that herd's population has been reduced almost 35% WITHOUT the removal of animals. But to achieve that, the management plan is very specific - basically, every mare has the chance to produce a single surviving foal with which to continue her genetics. Every horses contributes genetics, but not in an ongoing process--not year after year after year. That results in sterility eventually. But the mares are healthier, they produce their first foals when they're older (as in 5 or 6, not 2 or 3) and they don't keep having foals year after year.

Before PZP was started, no horse survived to 20 (in fact, the average age at death was much younger). One of the original mares died last year at 32. As Jay asks "advocates" against fertility control, "If it's so bad for the mares, why are they healthier and living longer?" But that's also a reason for ASIS' aggressive use of PZP - it is population control. Foals replace old horses, but now your horses are living longer because they're healthier - you cannot support multiple foals born each year.

Something else to think about - fertility control should NOT be used to "selectively breed" wild horses. Genetic viability simply means a population of animals that is able to reproduce - Do they breed successfully? Do the offspring survive? If yes, then yes, a herd is genetically viable. Kinship refers to horses' "relatedness." We want all genetics represented. [Insert opinion by me, Linda, here: the more representation of different genes you have--TJ's point of every mare producing a foal rather than selective breeding--the less in-breeding you get.]

I hope to slow population growth enough to show BLM significant cost savings, with the hope it puts some of that savings into building a temporary-holding facility and moves from helicopter roundups to bait trapping when necessary. Basically, my philosophy equals fewer horses born, fewer horses deemed "excess," fewer horses going into the unknown of the adoption pipeline (depressed in the current and foreseeable economy) or the unknown of the long-term holding pipeline - or worse.

Your organization has submitted a plan to the BLM, can you give us the highlights of that plan?

Our fertility control proposal is basically BLM's, by which I mean this: Nationally, BLM has acknowledged the benefits of fertility control. In our request to implement this program, we have volunteered to administer the program and do the darting. This saves BLM money and time, two things they have precious little of.

Basically, we proposed that it start with the next roundup so BLM can write the EA for fertility control at the same time they write the one for the roundup. Also, so we can start the "darting" while the mares to be released are in the chute, reducing our need to dart them in the field.

I got certified this summer to administer PZP by remote darting. During training, we also practiced with several different types of darting rifles. Our NMA/CO bought the rifle I thought would best suit our needs here, a CO2-powered rifle with a range up to about 50 yards. Now I'm practicing with that, hoping to be able to do some darting at a private sanctuary in the spring and continuing to learn all I can so we're ready when the BLM says yes.

What are the downsides, if any, to using PZP?

Fertility control addresses the reproduction cycle and does it simply by preventing fertilization of the mare's egg. Mares continue to come into heat, but although this has been seen as a downside by some "advocates," I haven't seen evidence of this.

PZP has the potential to cause sterility with prolonged use in consecutive years. ("The best available data indicates that six or seven years of treatment are required to cause orreversible infertility.") Although, for older mares or mares like Bones (healed fractured pelvis), sterility is not a death sentence. Everything has downsides.

Let me list some upsides: PZP is cheap. PZP costs $25/dose. Adjuvant is about $18 a "vial" - about 18 doses - you have to use the adjuvant to mix the PZP. The dart is $2.15. It is engineered to hit the mare (target is the big muscles of the mare's hindquarter), deliver the PZP dose and pop out nearly instantaneously.

Abscesses have gotten a lot of criticism from some. This is speculation, but it is thought that a cause of abscesses is dirt on the mare's coat that is pushed into the skin with the dart. Almost all of these clear up within a very short time. Ever seen a pristine mustang with nary a nick or cut or scratch or scrape?

Another big upside for me is the lack of handling - you don't have to hold a roundup; you don't have to separate mares, even temporarily, from their families; you don't have to immobilize (tranquilize) her. You don't touch her at all except with that dart, fired from a distance.

Do you have any unanswered questions about PZP?

I live my life with this belief: We never stop learning. Do I have unanswered questions? Sure I do! And there are questions I haven't thought up yet! And I'm sure the answers I do have will evolve as I learn more.

I wonder about the results, which we won't even start seeing until 2013 (primer in fall 2011, booster in spring 2012 - first foaling season we should see a reduction in foal crop: 2013).

Basically, I have every faith in the efficacy of PZP. I am confident in my training and my darting, but it's starting something new - like a first day at kindergarten - how will it go? Most of my questions are ones I think will resolve themselves with my own practice and experience darting mares. I have questions about how BLM will handle things - that, to me, is the biggest unknown.

(The pictures of TJs I included are in no particular order in the interview--many of them are mares and foals in the herd she follows who are part of the PZP-22 program already in effect. All the mares pictured have been treated with PZP-22. Also, TJ wanted me to add, in case it wasn't clear in the interview so far, her advocacy of PZP--or Mustang Contraception--is in response to wanting to end round-ups--please refer to the first part of this interview to read TJ's story of her first round-up.)

And, here's a link to TJ's Website: Spring Creek Basin Weblog


  1. Thank you BOTH for sharing this information!


  2. You're welcome. TJ is giving me an education--I'd sure like to think there's a better way to manage the Mustangs in the US. Maybe this is it--or at least a start. I'm amazed there's people like TJ out there taking the time to do this. I wonder how far she is from where you guys are?

  3. Thanks again Linda and TJ for posting this.

    It is true we never stop learning. I wrote about spaying mares because I had heard negative things about PZP, but I realize now it probably wasn't true.

    I agree 100% about less handling. I really hope the BLM listens to the suggestions from TJ's group. :)

  4. By the way, there's going to be more to this interview--TJ's going to tell us from first hand experience what has happened to the mares in her herd since they administered PZP-22 (with photos she's taken) and she's going to show us what her documentation project actually looks like. Maybe more people will be interested in doing what she does out here further west.

  5. Thanks so much for sharing this information! I do have one question though - what organization/group is TJ a member of? Not sure if I missed something - I was just curious. :)

  6. I didn't add that little bit of info...sorry--I'll let TJ introduce her group to you in her answer section. And I have a question for TJ, too--I cut up your answer so much to fit it into this blog post--can you tell us why you favor PZP over PZP-22? Thanks.

  7. There ARE people already doing darting in at least a couple of herds I know of. I take inspiration - educational and emotional - from them!

    I'm the president of the Colorado chapter of the National Mustang Association (our chapter is focused exclusively on the mustangs of Spring Creek Basin, but education of the whole benefits the specific). I'm also a member of our local Back Country Horsemen group and a member of a local group, Disappointment Wild Bunch Partners, which is made up of representatives of NMA/CO, two local Back Country Horsemen groups and San Juan Mountains Association, the nonprofit partner organization to BLM and Forest Service for San Juan Public Lands - of which Spring Creek Basin is part. There are five of us in that group, basically representing our groups in making suggestions and offering volunteer time and efforts to BLM on behalf of the horses.

    I favor PZP over PZP-22 for a few reasons: Much more data/research is behind PZP; it's much cheaper; it's less intrusive (don't have to round up horses to administer it); it has a very high efficacy rate when used effectively (90%+); and I think it can be used with more precision - because you don't have to round up horses, you can give it when it's most effective for the horses - not dependent on roundups. Also, and I hope this doesn't sound egotistical, but I am confident in my knowledge of my mares and confident in my ability to deliver a well-mixed dose of PZP to particular mares via dart rifle. Just call me Wild Horse Annie Oakley. ;)

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Please feel welcome to join our discussion by telling us about your own thoughts and experiences.