Celebrating the Wild Horse & Burro Act: Part Three: An unused solution

/ Staff Blog

Photo taken at RTF’s San Luis Obispo, Calif., satellite sanctuary by Meg Frederick.

This week marks the 50thanniversary of the enactment of the Wild Free-Roaming Horses and Burros Act (Public Law 92-195). Fifty years ago today, on Dec. 17, 1971, President Richard Nixon issued a signing statement (read Nixon’s full statement here) in which he said that he took “special pleasure … in signing strong new legislation to protect these noble animals.” The law may well have spared wild horses and burros from vanishing from the Western landscape, but it also placed wild horses and burros at the center of an ongoing struggle for the use of resources on our public lands. As we celebrate the passage of the Act, we’ve taken a look at wild horses before the law and its passage and what’s come since. Today, we’ll look at a possible solution for the challenges faced by what the Act calls “living symbols of the historic and pioneer spirit of the West.”

Historically and currently, wild horse and burro populations on our public lands have been and continue to be managed primarily through capture and removal: if numbers of horses or burros exceed what the Bureau of Land Management or U.S. Forest Service (USFS) have deemed appropriate for a specific Herd Management Area (HMA), those horses and burros above that population target number are removed. Those left behind continue to produce offspring, and so their populations again grow.

In a few years’ time, their numbers once again exceed what the BLM or USFS allow, and what the agencies call “excess” wild horses or burros are rounded up again: capture, remove, repeat.  This, on 177 BLM-managed HMAs.

There is a better way, and it involves slowing reproductive growth rates. Without utilizing fertility control immediately and in sufficient amounts, the endless cycle of capture-remove-repeat will continue, even if the numbers of wild horses and burros removed are huge.

Why hasn’t the BLM utilized fertility control?

The agency has repeatedly said it was holding out for longer-lasting methods for fertility control, kicking the can down the road for more than 25 years. There are also constraints of time and circumstance, such as contractors available to do the work, off-range housing for any animals that are captured, the great expense associated with almost as many wild horses living and being fed in holding facilities as there are on the range, regional politics surrounding roundups changing conditions on the range due to overuse and climate, and contentiousness about every decision BLM makes about the multiple uses of public land.

But does that excuse failing to prioritize available fertility control vaccines that would have at least begun to make a difference in those HMAs that are more easily accessible and the horses are more tractable?

Is there the money, staffing, and wherewithal to implement a well-run, successful fertility control program?  For years, we have all watched while wild horse advocates scream and the agency continues to do what it is comfortable with: rounding up and stockpiling horses at great expense and causing a crisis. Now, the impact of climate change is only growing with drought and fires increasing — impacts for which an agency charged with managing public lands must include in its planning.

While what Return to Freedom and most wild horse advocates want is wild horses to exist on public lands with little interference from humans, it is not plausible under current laws that retain the support of Congress. The Wild Free-Roaming Horses and Burros Act, as amended by the 1978 Public Rangelands Improvement Act, requires BLM to “determine appropriate management levels for wild free-roaming horses and burros on [designated] public lands,” making the agency responsible for how it should achieve these “Appropriate Management Levels” (AML) of horses and burros. It must do so under a mandate to manage our public lands for multiple uses (livestock grazing, hunting, energy extraction and so on) made law with the 1976 Federal Land Policy and Management Act.

In order to truly effect positive change as quickly as possible for wild horses and burros — to start moving BLM away from its decades-old practice of removing and warehousing wild horses — we must start now and not wait for wholesale change in Washington, D.C. We must work within the parameters which exist: limited HMAs, required multiple uses of public lands, fences and roads, human populations, and no predator control of the herds. These are not the parameters we want, but they are the confines within which we must work right now in order to have any positive outcome for the wild horses and burros roaming the range today.

The Porcine Zona Pellucida (PZP) vaccine is an elegant one. All mammalian eggs are coated with a membrane called the zona pellucida, which contains proteins necessary for sperm reception. When the PZP vaccine is injected into a mare, her immune system develops antibodies to the zona pellucida of her own eggs. In effect, the mare cannot become pregnant because her eggs will never “allow” for fertilization of the egg by the sperm. Ovulation can occur, natural reproductive behaviors can occur, but fertilization will not occur. Since PZP is a vaccine that must be boosted, if a mare does not receive a scheduled injection, she may still become pregnant. What this means is that in terms of population management; PZP slows — but does not altogether stop — reproduction. Thus, it is a simple and effective tool for stabilizing a population of animals.

There are other population management techniques, and these include doing nothing at all and allowing nature to take its course; separating mares from stallions; gelding all males; or offering up “excess” horses through adoption or sales that place them at risk of falling into the slaughter pipeline. None of these options works very well, either because on open rangelands they are so intensive as to be limiting, they result in potential behavioral change, they are unsustainable, or they are unacceptable to some portion of stakeholders or the public at large.

Natural herd behavior and social interactions, and in-the-wild-management can be attained, however, through thoughtful, less-invasive forms of proven, safe and humane fertility control like PZP.

The ideal safe, effective contraceptive techniques have the following characteristics (Kirkpatrick and Turner 1991): 1) Contraceptive effectiveness of at least 90 percent; 2) The capacity for remote delivery with minimal handling of animals; 3) Reversibility of contraceptive effects; 4) Safety for use in pregnant animals; 5) Absence of significant health side effects; 6) No passage of the contraceptive through the food chain; 7) Minimal effects upon individual social behaviors; 8) Low cost.PZP has these attributes, and this is why it is beloved and trusted by so many in the wild horse advocacy community.

The PZP vaccine must be boosted annually. This is a challenge when considered for broad-scale use. Some horses will not be approachable from year to year. Some are never approachable. And some live so remotely as to be inaccessible for someone carrying a dart gun loaded with the vaccine.

An updated iteration of a longer-acting PZP vaccine called PZP-22 is a promising advancement.  This vaccine could provide up to 4 years’ protection, and maybe more, after a well-timed initial primer and booster.

Different, also longer-acting vaccines or methods have garnered interest from and limited use by BLM. One vaccine of note, GonaCon, is a hormone antagonist, which means that it interrupts the hormone cascade that leads to the ability to become pregnant. While we are not against further research into safe and humane methods of fertility control, we remain guarded when it comes to GonaCon: it is hormonal, which could lead to unforeseen behavioral changes, and it has not been studied for as long or as well as PZP vaccines. While advances have been made with creating “better” intrauterine devices (IUDs) that are softer and more flexible, we do not yet support the use of IUDs in wild free-roaming mammals because there has not yet been enough proof of its comfort and safety.

From the late 1990s on, RTF and other advocates have called for real implementation of fertility control to manage wild horse and burro herds and to move away from costly, unsustainable, dangerous and unpopular roundups and removals, yet BLM has utilized fertility control on paltry few HMAs, and even on those has underutilized it.

Most recently, rather than invest in broadly acceptable fertility control, BLM has instead wandered into the dangerous territory of proposing the surgical sterilization of wild mares. While it may sound reasonable to perform a procedure on a mare that would then never need to be handled again, the surgery itself cannot be performed to protocol on a fractious mare in a chute who cannot easily be treated afterwards for pain or complications. And who would perform these surgeries, on how many mares?  It’s an untenable and upsetting fertility control methodology. Return to Freedom filed a lawsuit saying as much, and the BLM has seemingly dropped this idea — for now.

BLM has never spent as much as 4 percent of its budget on fertility control. The agency’s mantra has always been that fertility control would only be useful and effective if it were implemented when the agency-set AML has been achieved — AMLs that advocates including RTF believe are arbitrary and not grounded in science. Conveniently, AML has never been achieved, so BLM has never had reason to utilize fertility control on a programmatic scale. Instead, the agency continues to aggressively ramp up removals.

But there must be immediate implementation of fertility control. Indeed, the BLM Wild Horse and Burro Advisory Board recommended as such in its September 2020 meeting: “The Board recommends that the agency expand fertility control implementation and develop measurable objectives outlining a targeted reproductive growth rate reduction and multi-year plans, on an HMA-by-HMA basis. The effort should include fertility control treatments combined with gather operations, including HMAs where AML will not immediately be achieved. The Board recognizes that reproductive growth rates on the range must be reduced immediately so that overall numbers of horses or burros, as well as overall numbers of gathers, begins downward trending.”

Diverse stakeholder groups have arrived at similar conclusions through modeling and peer-review research analysis: a slower and multi-faceted approach to wild horse and burro management must be done alongside the BLM’s removals, some on-range fertility control (via remote darting), and/or some gather-administer-release fertility control if we are going to see the agency’s capture and remove policy change within the next 5-10 years.

Fertility control should not be implemented only when AML is achieved, but as a way to begin stabilizing the population immediately. This is more effective at creating and maintaining sustainable wild horse management with less dependence on transportation and “short-term” holding corrals, where a majority of the BLM is spending its program budget.

To reduce stress on overcrowded holding facilities, contractor availability, and taxpayer dollars, the application of immuno-contraceptive vaccine alongside BLM’s gather-removals allows for stabilization and then reduction, where necessary, of wild horse or burro numbers. It is also more economically and logistically viable: population growth rates on the range are reduced, and time between roundups can be extended.

When BLM conducts roundups, fertility control vaccines should be reapplied to mares or burro jennies that have received initial doses and new mares can receive treatment and be released, in effect scaling up fertility control at every opportunity.

We don’t like or want horses removed from their ranges. Barring a major shift in Congress and legal changes, however, fertility control is the fastest way to move BLM away from continuing to rely on as roundups as its primary management tool. Though expensive on the front end, it would result in wild herds truly ranging freely, with the least amount of interference by us.

Congress has awoken and is at last willing to fund safe, proven and humane fertility control. Appropriators have said as much in recent budgetary language. Broader stakeholders than ever before are now supportive, and demanding the use of, fertility control. Yet the BLM continues to hesitate, yet again, in actual use. In our ongoing effort to end ceaseless roundups, RTF will continue to lobby Congress to hold BLM’s feet to the fire on the implementation of fertility control.

Read Part One: A reintroduced native species

Read Part Two: Saving wild horses

Take Action: 8 Ways to Help America’s horses