<p>Ben Masters stands in a field of invasive cheatgrass in Nevada’s Antelope Complex HMA, an area with eight times the Appropriate Management Level of wild horses. Cheatgrass is unpalatable most of the year, can outcompete native plants, and increases the fire regime from a century or more to every few years. Fifty million acres of the American West is dominated by cheatgrass.</p>

Ben Masters stands in a field of invasive cheatgrass in Nevada’s Antelope Complex HMA, an area with eight times the Appropriate Management Level of wild horses. Cheatgrass is unpalatable most of the year, can outcompete native plants, and increases the fire regime from a century or more to every few years. Fifty million acres of the American West is dominated by cheatgrass.

Photograph by Charles Post

The Future of America's Wild Horses: The Options

Tens of thousands of wild horses roam the American West, and the ecological consequences of their increasing numbers could be dire. Here are some solutions for keeping herds and rangelands healthy.

Seventy-five thousand wild horses and burros in the American West are caught in a political, emotional, and environmental controversy with two questions at its source: how should our public lands be managed, and how is “good” land management defined?

Legally, there are only supposed to be 27,000 wild horses and burros for “thriving natural ecological balance” in the area in which 75,000 now roam. There are another 45,000 in government holding pens, gathered to prevent overgrazing, that are costing the agency nearly $50 million annually. The ecological consequences of mismanagement are staggering.

The Bureau of Land Management is caught in gridlock of lawsuits filed by a variety of interest groups that has hindered the agency’s ability to take action, including administering fertility control on wild horses. So, what are the options, and what is realistic?

Fertility Control

The most widely used wild horse fertility control is PZP, Porcine Zona Pellucida, which TJ Holmes uses in Spring Creek Basin Herd Management Area in southwest Colorado. PZP is about 90 percent effective at preventing pregnancies. The mares have to be given a primer dose, a booster dose four to six weeks later, and additional boosters every year after that.

The prerequisites for PZP to work are a herd size that isn’t already over the target size, excellent documentation of the horses, dedicated trained volunteers, access to the horses, and a local BLM staff willing to work with those volunteers. Successful PZP programs are typically smaller herd areas with easily identified horses and passionate local volunteers.

For PZP fertility control to be effective on a herd numbering thousands of horses, the animals would have to be gathered via helicopter, processed and given the two PZP doses, and then released back into the wild. After that, those horses would have to be regathered annually to have the PZP reapplied.

If wild horse populations were reduced to a manageable level and fertility control was applied to the point where population growth equaled the adoption demand, then we would have a publicly acceptable and sustainable program moving forward. Theoretically, this would work but it would require tens of thousands of horses to be rounded annually, hundreds of volunteers would have to be certified in PZP, and millions of more dollars would have to be allocated by Congress to the BLM.

PZP fertility control is currently administered to fewer than 1 percent of the wild horses and burros annually. While there is lots of room for PZP fertility programs to expand, it cannot be relied upon alone to put the program back on a sustainable track.

Trap, Neuter, Return

Although millions of dogs and cats are spayed and neutered annually, the BLM receives harsh criticism and lawsuits from activist groups when they try to conduct research or spay mares. If permanent sterilization became an option, it would allow the horses to live out their lives in the wild as a non-breeding population rather than in a holding pen. Trap, neuter, return is not an option the BLM is currently considering.

Adoption, Rescues, and Sanctuaries

More than 2,300 horses and 300 burros were adopted in 2015. Half of those were adopted out by the nonprofit Mustang Heritage Foundation through innovative programs such as the Extreme Mustang Makeover and Trainer Incentive Program. Although the BLM annually spends more than $6 million in adoption expenses, they’re competing in an extremely saturated horse market with untouched wild mustangs that can be dangerous or otherwise undesirable.

In attempt to keep wild horses from going to slaughter, the BLM doesn’t give adopters title to their horse until a year after adoption. This well-intended but restricting red tape makes it difficult for trainers to have turnover of horses and the rural horse-owning demographic typically doesn’t like the federal government to control the livestock on their land. While adoption will continue to play a role in managing wild horses, it will not solve the problem because only 2,500 horses and burros are adopted annually with 10,000 being born each year.


In September 2016, the volunteer citizen BLM Wild Horse and Burro Advisory Board, of which I am a member, voted seven of eight for the BLM to destroy unadoptable horses in holding pens in as humane manner as possible. Many wildlife conservation groups applauded our recommendation because it would alleviate overgrazing on public lands that is jeopardizing wildlife habitat.

Although the Wild Horse and Burro Act explicitly states the “the Secretary shall cause additional excess wild free-roaming horses and burros for which an adoption demand by qualified individuals does not exist to be destroyed in the most humane and cost-efficient manner possible,” in 2016 the BLM released an official statement saying they have not and will not euthanize healthy horses. The majority of wild horses that enter into the BLM captivity system of living in feedlots and holding pastures will eventually be euthanized in their old age, after they’ve accrued the cost of $50,000 per individual. Yet euthanizing healthy horses is not currently an option the BLM is considering.

Sale Without Stipulation

Selling the wild horses in holding facilities without stipulation would people to buy them and send them to slaughter. Because the USDA stopped inspection funding for domestic horse slaughter, they would have to be transported to either Canada or Mexico. The meat would be then used for human or pet consumption. This scenario would be the worst possible outcome for most animal rights organizations. The transportation to foreign slaughterhouses can take days, and horses, which are prey animals with a strong flight instinct, are inherently difficult to kill and process. If the BLM sold the horses without stipulations, it is likely that thousands of horses would be adopted by private individuals, sanctuaries, and concerned citizens first.

Selling the horses outright would also make them more attractive for horse trainers because they are more marketable without the one-year adoption red tape. In other countries that have free roaming horse herds, such as Canada, New Zealand, and Australia, excess horses are typically gathered and put up for adoption, and all unadopted horses are slaughtered for either human or pet food. Selling wild horses and burros in holding pens without stipulation is not currently an option being considered by the BLM.

Expanding Range or Allocating Forage from Livestock

Nationally, the 75,000 wild horses and burros on BLM herd management areas will utilize about 900,000 Animal Unit Monthly (AUMs) of forage in 2017. In 2013, the most recent year I could obtain data, livestock operators were allocated 1.1 million AUMs on the same lands as occupied by horses. Many of the livestock AUMs have decreased or go unused making the livestock to wild horse ratio about 1:1 on areas they both exist. While the AUM usage is comparable, the livestock AUMs are dictated by time of year, length of use, and the number of animals whereas wild horses utilize the landscape year. As wild horse numbers continue to rise, the BLM will likely restrict and take away more grazing permits from ranchers that operate in wild horse areas. Some Herd Management Areas still have room to allocate forage from livestock to wild horses while ranchers in other Herd Management Areas have already had their permits revoked or diminished, or have had them taken non-use from lack of forage.

While more public lands could theoretically be opened up for wild horses, land managers and other agencies are hesitant to take breeding herds because they’ve seen the disaster the BLM has gotten into. Even if the land size for wild horses was tripled and they were allocated 100 million acres, within a few decades they would reach capacity on the expanded range and the problem would still exist, just in a much larger state.

Expanding Holding Pens

As of August 2016, there were 12,430 wild horses and 1,081 burros in short-term feedlot-style holding corrals, another 31,588 horses in long term pastures, and 562 in subsidized eco-sanctuaries. The annual bill to keep these horses alive and healthy is nearly $50 million. The possibility exists for Congress to allocate a larger budget for holding pens that would allow the BLM to gather excess horses to alleviate pressure on the range. Most people don’t consider this a valid option because the BLM logistically can’t find enough places to put the horses in long term pastures, and even if they did find pastures for an additional 10,000 horses each year, that only keeps up with the current population growth in the wild.


Most big game populations in North America are controlled by predators, hunting permits, and culling. For example, elk in Yellowstone National Park were causing ecological damage prior to the reintroduction of wolves. When wolves were introduced in 1994 and the park’s elk herd diminished, wetland habitat was restored. Bison in Yellowstone, on the other hand, don’t have enough predation by wolves, can’t migrate out of the park, and are culled to control population sizes with meat going to Native American tribes.

Although predation does impact wild horse and burro populations in some areas, historically it has not been enough to control population sizes on a national level. While it’s theoretically possible for the BLM to enact a cull program, with meat going to zoos or animal shelters, the BLM is not considering lethal culling now.

Natural Regulation

Natural Regulation is letting nature take care of itself. The problem with natural regulation is that “natural” is difficult to quantify and most scientists consider horses to be feral livestock and not a native species. Over the past 250 years in the American West, humans have created conditions of island biogeography for large herbivores and subjected them to a boom- and-bust cycle.

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There are examples of “natural” regulation with wild horses. A New York Times article shows that the BLM was in a similar state of emergency in 1991, only back then it was smaller and more manageable. The 400,000-acre Nevada Wild Horse Range located in the Nellis Air Force Base had been ignored for decades. Although the Appropriate Management Level of the Nevada Wild Horse Range was 500 animals, a lack of roundups grew the herd to over 6,000 animals. “The Indian rice grass and tall Shadscale that should nourish the horses is long gone, replaced by inedible rabbit brush and noxious weeds. Deer and antelope have been forced from the land for lack of food,” the article said. “The milk supply of many mares has dried up, and so the colts starve. Other colts are orphaned or abandoned, and some fall by the wayside as the mares hobble from water to forage. The colts being nursed in Reno have bloated bellies and hooves too sore to walk on. Realization comes too late.”

Fast forward to 2015 and go a hundred miles south of the Nevada Wild Horse Range to the Cold Creek Area of the Wheeler Pass Herd Management Area. The Appropriate Management Level of this HMA is 47 to 66 horses and 20 to 35 burros. In 2015 the estimated population was 356 to 427 horses, approximately eight times the Appropriate Management Level. The official emergency gather document states, “Severe drought conditions and an overpopulation of wild horses have resulted in emergency conditions within the Wheeler Pass Herd Management Area that pose an imminent threat to wild horse health and well-being.” Ultimately, hundreds of horses were gathered in an emergency roundup and 30 were euthanized.

Twenty-five years after the Nellis Air Force base disaster, hundreds more horses were starving at the Cold Creek Herd Management area, a hundred miles away. The BLM conducted an emergency roundup and dozens had to be euthanized on the spot because they couldn’t be saved.

While natural regulation sounds enticing, most people don’t want to sick or dying horses. And in the case of the BLM, it has never allowed natural regulation to truly occur because public outcry forces them to conduct emergency gathers. But with wild horse populations at an all-time high, would the BLM be able to save tens of thousands of horses starving to death, rather than just a few thousand?

BLM Response

The BLM Wild Horse and Burro Program is on an unsustainable path that seems to be at or leading to natural regulation, potential starvation, and destruction of public land. I spoke with Neil Kornze, the director of the BLM at the time of our interview. I was encouraged and a little surprised when he agreed to go on record.

I asked, is there a sustainable path forward? “We ran 12 different scenarios and at least one of them was able to get us back to a sustainable population, I believe, within a 15-year time frame,” Kornze told me. “We looked at PZP because it’s the only thing we have today, and said to ourselves, ‘what portion of the population would need application?’ We were looking at bringing 70 percent of the horses off the range each year, treating the females, and turning them back out. We saw a 20 percent increase in adoptions this year, so we have some hope of a positive trend there. I think, with existing tools, that there is a pathway, but we would need to nearly double the funding to make that possible.”

During George W. Bush’s administration, the Wild Horse and Burro Program’s budget doubled. It doubled again under President Obama. Kornze’s suggestion would take it the budget from $80 million to $160 million. Although I’m on the Wild Horse and Burro Advisory Board and have studied the issue closely for the past six years, I’ve never seen the 15-year plan for the BLM to get the program back on a sustainable track. I requested the plan from Kornze and his staff but never received it.

Under the Trump administration, Ryan Zinke was appointed to be the Secretary of the Interior and Neil Kornze is no longer the director of the BLM. Kristin Bail will serve as acting director until a new one is appointed. Until then, the future of the Wild Horse and Burro Program will remain uncertain.

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