Think Out Loud

Bureau of Land Management wants to test new ways to manage wild horse population

By Rolando Hernandez (OPB)
Aug. 9, 2022 5:19 p.m. Updated: Aug. 16, 2022 9:07 p.m.

Broadcast: Tuesday, Aug, 9

A wild stallion gallops across the high desert near Steens Mountain in southeastern Oregon. The South Steens Herd is among the easiest wild horse to see because they wander close to Highway 205 south of Frenchglen, Ore.

The Bureau of Land Management wants to test three new contraceptives to manage the wild horse population. Advocates disagree with this approach and believe the focus should be on the land horses are allowed to graze.

Vince Patton/OPB


If not managed, the number of wild horses grows by about 20% every year according to the Bureau of Land Management. In Oregon, there are about 4,500 wild horses but, according to the BLM, the state can only sustain about 2,700. The federal agency is looking for public comment on a research proposal for three new contraceptive methods. But, some horse advocates disagree with this approach. Rob Sharp is the Supervisory Wild Horse and Burro Specialist for the BLM Burns District. Gayle Hunt is the President of the Central Oregon Wild Horse Coalition. They both join us now to share their perspectives on what should be done about Oregon’s wild horses.

The following transcript was created by a computer and edited by a volunteer:

Dave Miller: From the Gert Boyle Studio at OPB, this is Think Out Loud. I’m Dave Miller. For a few years now, the Bureau of Land Management has used a contraceptive called PZP to control wild horse populations, but the agency says the numbers in Oregon are still too high. So now they’re planning to test three new contraceptive methods and are asking for public comments on their plan. Some horse advocates disagree with this approach. We’ll hear about their concerns in just a few minutes, but first I’m joined by Rob Sharp. He is a Supervisory Wild Horse and Burro Specialist for the Bureau of Land Management’s Burns District. Rob Sharp, welcome back to the show.

Rob Sharp: Good to be on Dave. Thanks.

Miller: It’s been four years since we last spoke. What has happened with Oregon’s wild horse population over that time?

Sharp: Last four years, we’ve seen steady increases in the on-range populations, up until about this time a year ago. Most of the viewers recognize the major drought that we had last year and that in parts of the states we’re presently experiencing again this year. Last year, we removed over 3000 animals from the range within the state of Oregon, just in response to emergency conditions – trying to help the animal conditions in the face of declining water and forage conditions out there. Right now, we are sitting on a population of approximately 4500 developed animals across the 18 herds the BLM manages within the state. Including this year’s full crop, that’s still roughly double our target population of approximately 2700 animals.

Miller: When you say that you removed 3000 last year, what happened to them?

Sharp: Every animal that we removed was brought to a BLM off-range holding corral similar to the corral here in Burns. A lot of those animals were brought into Burns, where we give them a vet inspection, prepare them for adoption, and then hopefully place them into private care through our adoption or sales program. Those animals that aren’t adopted eventually end up being transported over to midwestern off-range pastures where they live out the rest of their lives [in a] semi free-roaming environment.

Miller: So what are your projections for what would happen if you continue your current process of using this PZP contraceptive?

Sharp: The challenge faced with the BLM in fertility control to reduce the annual population growth rate on the range is we lack tools that provide for long duration contraception. When I say long duration, I’m talking vaccination or techniques that last longer than approximately two years. There are certain programs where animals are being re-treated annually with our current formulations of PZP. That is having an effect, however that does take a lot of people power and budget to intensively manage individual herds that way. Left unchecked – those instances where we cannot effectively treat a mare with either a longer duration vaccination, or IUD, or not treat the mare at all, we just continue to see that 20% growth rate every year, leading to population doubling every four or five years.

Miller: Can you explain how the PZP applications work right now? How are either BLM employees or volunteers administering this contraceptive method?

Sharp: We administer two, presently two varieties of PZP, and then a third immunocontraceptive called gonacon equine. Those can either be administered in conjunction with a gather, where we have those mares in a holding facility, being able to administer it via hand injection in a chute. We also have the ability to remotely deliver – via dart gun – the liquid forms of both ZonaStat-H PZP for total control as well as gonacon equine. We have – In the state of Oregon, we have several specific herds that are actively being managed to apply – in this case, it’s gonacon equine – for total control vaccination through remote darting. That started as volunteer efforts, has transitioned into contractors assisting us with applying those vaccines.

Miller: And the remote dart gunning of this contraception that lasts for something like 2-3 years – is that done on horseback, or quads, or from helicopters? How is it actually being done?

Sharp: No. We just try – because the herds are – exhibit truly wild behavior. They’re not approachable, they’re very skittish of people or anything new out there. Our cadre of BLM and contract darters are actually staffing water holes – places where animals want to naturally come to get a drink of water – staffing them pretty much day and night, around the clock, to reliably identify a mare and deliver a dose of fertility control.

Miller: Can you describe the three novel forms of contraception that you’re proposing to use – or to try out – instead?

Sharp: Our BLM Wild Horse and Burro research team is proposing – two of the trials are looking at different varieties of immunocontraceptive fertility controls, looking at different adjuvant, which is the product that creates the immunoresponse that results in whether the vaccine is effective or not, and how effective. Two different varieties of that: One is a continuation of research that began almost two years ago now at a holding facility down in Nevada. A second is a reformulation of a PZP variant known as a SpayVac, hoping to have efficacy of multiple years instead of just one or two years with our present formulation. The third is actually – it’s not a vaccination. It’s actually a different shape of a flexible intrauterine device – IUD, if you will – to be placed into non-pregnant mares at the time of capture.

Miller: Is the basic idea for all of these that it would give you the same ability of population control, but with less people power over time – you could control the populations through less human work?

Sharp: Yes, that is the intent: both less human work as well as less – I guess impact on the horses themselves. If we are having to gather those animals to re-treat with fertility control, the longer that we can space that timeframe out, the less stressful it is to the animal, the less it costs the government and the American taxpayers. So, that is the intent. Just longer lasting formulations.

Miller: You’re going to hear from a critic of BLM Wild Horse policies in just a minute or two, but one of the most basic arguments that we’ve heard for many years now is that the problem is not necessarily the number of horses on rangeland in the West, it’s the number of cows. Can you give us a sense – just for the overall numbers here – so we can have it in our head? You had noted that, right now, there are about 4500 wild horses in Oregon and the target population is 2700. How many cow-calf pairs – Or, how many cattle are there?

Sharp: Last time we looked at the allocation of forage between permitted domestic livestock grazing and wild horse and burros – that number is approximately 30% – 20-30% of that forage allocation goes to our target population of wild horses or burros within the state, the remain of which goes to permitted domestic livestock as well as forage allocations for wildlife habitat.


What’s important to point out, though, is that stocking rate – that’s what we call it in our industry – of wild horses and burros is less than that domestic livestock grazing, just because of the nature of that grazing impact on years like we’ve had – drought years. We don’t have the ability to make the call in the spring, that hey, we don’t have enough rainfall to grow grass and fill water holes, to provide for all the forage allocations, when it comes to wild horse and burro. That’s a direct contrast to how we manage permitted livestock raising. We can make those spur-of-the-moment decisions, in terms of how many animals we put on the range, and it’s completely variable year in and year out. I will say that since BLM has been managing wild horse and burro – since the passage of the 1971 Act – actual livestock raising – permitted livestock raising use, across all BLM lands that overlap with wild herds, has decreased by approximately 30%.

Miller: Are you talking about acreage right now, or the number of animals – of livestock on the land?

Sharp: Yeah, not necessarily a number of animals, but the animal unit month allocations – that’s how we allocate forage to grazing animals, be it wild horses or domestic livestock

Miller: Rob Sharp, thanks very much for joining us.

Sharp: Thank you.

Miller: We’re talking right now about the BLM’s proposal to test three new contraceptive methods to control the population of wild horses. The agency is accepting public comments on their plan through August 22nd. For another perspective on this, I’m joined by Gayle Hunt. She is the President of the Central Oregon Wild Horse Coalition. Gayle Hunt, welcome to the show.

Gayle Hunt: Thank you very much. It’s really great, for once, to have an unedited voice. So, if I’m misquoted, I guess that’s on me. It’s also a great honor to be on the show with Rob Sharp, because I know him to be one of the best there is in BLM. We have really enjoyed working with him over the years, until the paradigm kind of changed to a fear on the part of the advocate community that we’re just losing the number of wild horses and burros out there as well as their genetic identity. Our concern is more about the nationwide direction of this research proposal rather than what happens in Oregon. Because, if there’s any place that I would have some confidence level that our horses are treated well and ethically, and that the message is being projected honestly, it would be in Oregon.

Miller: Let me start with the big picture here. Actually, in Oregon – because, as we just heard, the Bureau of Land Management’s stated goal seems pretty straightforward – even if there are big questions about how this should or could be accomplished. But, they’re saying there should be 2700 wild horses on rangeland in Oregon. What’s your goal?

Hunt: My goal, personally, is again, not so much as how many we should have in Oregon, but in 10 Western states. The national AML is around 26 hundred, 785 or something – don’t quote me, but – yes, I got it right: 26,785.

Miller: What is an AML?

Hunt: That unfortunately is the high end of the AML. AML is viewed as a range. And, if that’s the high AML, we don’t even know what the low end of the AML would be.

Miller: I am sorry, I don’t know what an AML is.

Hunt: Appropriate Management Level.

Miller: Okay, so you’re focusing on the 10 Western states, not just Oregon?

Hunt: Correct. As I say, I’m not as concerned about what happens in Oregon because I think we do have some of the best managers out there, thanks to Rob. Our consternation here is that, with that number of approximately 26,000, BLM is openly saying that that is more or less what there was when the 1971 Wild Horse Burro Act was passed. There’s a – BLM’s own contradiction of that – that they really had no idea how many horses they had in 1971. In fact, they allude to knowledge that it was probably a whole lot more than 26,000 in 1971. So, what we’re in essence doing by acquiescing to that national AML is saying that we’re willing to take this wild horse and burro population down to numbers that were potentially even lower than when Wild Horse Annie introduced the bill. It was passed unanimously because it was widely known that the horses were in trouble at that number.

Miller: Do you have a point of view on the particular plan that is open for public comment right now to test these three new methods for contraception in wild horses?

Hunt: We are not really in a position to pick this apart on a technical basis. In fact, it’s important that it’s known that our organization, and all of the serious wild horse advocate associations I could name, would never say that we don’t need fertility control, population control removal, other intelligent ways of managing the herd. Our problems are more about the underlying assumptions in this research proposal, and in many other proposed actions, that do assume that we need to get the nationwide number down to 26,000, and that we have over-populations, we don’t have too many livestock.

That doesn’t even mention the extractive industries such as oil, and gas, and soon-to-be lithium, precious metals. There’s a lot of people wanting a piece of the public lands that the horses and burros are allocated under this act. What we see in this proposal is some deviation from what the Wild Horse and Burro Act originally said. They said it with clarity – it’s not an ambiguous law, especially when you consider the intent. So, the concern of advocates is that we really need a do-over with how agencies interpret the Wild Horse and Burro Act and how they implement the Act.

Miller: And just to make this as clear as possible: You’re saying in order for there to be enough rangeland, and grass, and water, in particular, for wild horses in the West – it’s up to the BLM to perhaps reduce the number of cows that are on the range. Is that – if you strip it down, is that essentially what you’re arguing?

Hunt: In part, but we also acknowledge that even if we were to eliminate all extractive industry that’s competing with the horses’ habitat and the very health of the land, there’s still gonna be a wild horse number that is going to max out. And so, we would only be prolonging the inevitable and we’re not in favor of that. We’re not so stupid that we wouldn’t see that coming. But for now, the livestock on public lands is not just a horse issue. When I was hauling hay for my eight horses – mostly wild – a few weeks ago – it happened to be during our heatwave – and I wasn’t real happy with climate deniers at that point – we have issues that go far beyond the needs of wild horses and burros on these same public lands.

We need to be looking not at just the effects, such as drought, that we have to deal with wild horse management. We have to deal with what are the causes – and those causes really do need to encompass livestock usage. They’re ruminants, they make a lot of methane, and horses make a very small fraction of that, and have some restorative qualities as well. If we can’t see this opportunity that is facing us as we look at yet more three-digit temperatures in a week or so again, then, you know, we just have no vision. There’s an opportunity here to do so much good, if we sit down, and overcome the polarization, and look at what are the real issues on public lands. We’re about horses, and we’re about burros, but we’re also about a planet that’s going to sustain the rest of creation for the foreseeable future. That is in our hands, too.

Miller: Gayle Hunt, thanks very much for joining us. I appreciate it.

Hunt: Thank you.

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