Frequently asked questions about the overpopulation of wild horses and burros on federal lands

Q: How are wild horses and burros defined in the U.S.?

A: Wild horses and burros are defined by federal law as unbranded, unclaimed, free-roaming horses or burros found on public lands in the United States. Most wild horses and burros living today are descendants of animals that were released or escaped from Spanish explorers, ranchers, miners, the U.S. Cavalry and Native Americans.

Wild, free-roaming horses can be found on public lands across 10 western states, with the largest population in Nevada. Wild burros roam rangeland in California, Nevada, Arizona, Utah and Oregon.

Q: Why are these animals managed by the U.S. government?

A: The Wild Free-Roaming Horse and Burro Act of 1971 (Public Law 92-195) gave the Bureau of Land Management (BLM) and the U. S. Forest Service (USFS) the statutory obligation to manage and protect wild horses and burros in designated federal management areas. This law authorizes the BLM to remove excess wild horses and burros from the range to sustain the health and productivity of public lands.

While all free-roaming equids in the U.S. may be considered feral, only the subset designated by the Act have the legal protections of “wild horses and burros.” Free-roaming horses and burros that inhabit tribal, state or private lands are not protected under the 1971 Act.

Q: What is the scope of the problem?

A: Overpopulation is the number-one threat to wild horses and burros and the lands on which they roam. The BLM calculates an appropriate population management level based on the number of wild horses and burros that can thrive in balance with other public land resources and uses. Currently, the number of wild horses and burros on public lands is three times greater than the appropriate management level determined by the BLM. The BLM-designated level is approximately 27,000; the national estimated on-range population as of February 27, 2019, is approximately 88,000. Currently, an additional 50,000 (August 1, 2019) horses are maintained off-range in long-term holding facilities.

In some herd management areas, overpopulation has created welfare risks for wild horses and burros, such as starvation and dehydration due to scarce food and water resources, especially in those areas with arid geography. In 2019, the BLM conducted an emergency gather of horses in the Red Rock Herd Management Area in Nevada because of no sustainable water sources and range degradation.

Q: What is off-range holding?

A: Off-range holding can be short-term or long-term. For short-term holding, horses are likely to be held in corrals and small paddocks. For long-term holding, horses are likely to be held in pastures owned by private citizens who have contracts with the federal government. Horses in short-term holding are evaluated for adoption and are vaccinated against common equine diseases in preparation for potential placement. Horses that are over the age of 10 or those that have been offered for adoption unsuccessfully three times may be moved to long-term holding facilities. The horses placed in long-term holding are meant to be managed in a way that is similar to their state on-range, meaning there is minimal handling and intervention. Horses in long-term holding are grouped by sex, and most receive supplemental feed during the winter to assist in maintaining body condition. Horses in long-term holding do not receive routine veterinary care. If they are found to be significantly ill or injured a veterinarian may be called for euthanasia.

Q: How is overpopulation currently addressed?

A: Multiple strategies are employed by the BLM in its efforts to control herd sizes. The yearly removal of animals from the range is the method with the greatest impact. Over 11,400 wild horses and burros were gathered in 2018. Horses and burros removed from the range are assessed for adoption suitability. Those that are not suited for adoption are placed in long-term holding facilities. The costs for care and maintenance of horses in these facilities account for 60% of the BLM’s annual budget.

Fertility control vaccines were administered to just over 700 mares last year. This method is currently limited because the vaccines must be administered by hand or by dart and the duration of effectiveness is short (one to two years), necessitating annual revaccination with repeated boosters. While fertility control can be an important herd management tool, a very high proportion (about 80-90%) of mares must be vaccinated with an effective product in order to substantially suppress population growth. Repeatedly gathering horse herds annually becomes increasingly difficult due to horses’ avoidance behavior making it unlikely that a sufficient number of mares can be treated to meaningfully slow population growth. Other strategies used by the BLM include adoption and sale into private care (3,158 animals in 2018).

Q: What solutions are proposed by the AAEP and AVMA?

A: An expanded combination of population-control methods and removal strategies is necessary to return the wild horse and burro population to levels that optimize the health of the animals. The AAEP and AVMA support the ongoing development and use of long-lasting, effective contraceptives. In addition, the AAEP and AVMA support the use of permanent sterilization methods, such as spaying or castration, in selected herds where repeated capture or darting with contraceptive vaccines is not feasible.

In addition to the BLM’s continued removal of animals from areas where the range cannot support the population, the AAEP and AVMA encourage the agency to pursue new adoption and sales strategies. These may include collaboration with private enterprises within the horse industry, as well as with public sector and non-governmental organizations that would utilize the animals for recreation or companionship. Placement in privately funded sanctuaries also should be pursued.

Finally, if the above strategies are not successful in reducing the size of at-risk herds, the unrestricted sale of horses over the age of 10 that are being kept in long-term holding facilities or those that have been offered for adoption unsuccessfully three times should be considered by the federal government. Unrestricted sale means that wild horses and burros can be sold on the open market like other domestic horses in the U.S. Approval for unrestricted sale was incorporated into the Wild Free-Roaming Horses and Burro Act by amendment in 2005; however, the federal government has chosen not to allow this option to date.

Q: Is spaying humane?

A: Ovariectomy (the removal of the ovaries) is a surgical procedure that permanently sterilizes a mare. The technique proposed for use in the wild horse and burro population is ovariectomy via colpotomy, which is performed by making an incision in the vaginal wall and then using a device to separate the ovary, much like what is done when a testicle is removed during castration. Mares should be sedated, and multimodal pain management used. When performed by a veterinarian experienced in the procedure, ovariectomy via colpotomy may provide an efficient method for sterilizing horses in the wild. However, it must be noted that this procedure requires exceptional skill.

Because this procedure has only been performed on a small number of wild horses, the safety and practicality of spaying wild horses on a large scale remains unknown. Research by Collins and Kasbohm 2017, noted a 2% mortality rate due to complications from permanent sterilization techniques including surgically vasectomized and chemically epididymectomized males and surgically ovariectomized females. No wild horses and burros currently under BLM management are being spayed, but a research study with a limited number of mares has been proposed in order to gain additional knowledge about how to most humanely perform this procedure in the field. Ongoing research into other methods of permanent sterilization should be undertaken. Permanent sterilization is an important management tool because it removes the need for repeated treatment of mares with temporary fertility control. Repeated handling of feral horses brings increased risks of injury for those horses and the people handling them.

Q: What are other groups doing to solve the overpopulation problem?

A: Current strategies are not effectively addressing the issue. Several options for population management are widely endorsed by multiple stakeholders, including expanded fertility control through vaccination, more horses removed from the range and new adoption strategies to place more horses in private care. Management of the wild horse and burro populations is made more difficult due to the expansive and rugged areas in which they roam. While removing horses from the range and providing fertility control in areas where that can be achieved successfully are critical, repeated attempts to capture feral horses and burros will likely result in an increased risk of injury to both horses and people, especially if inexperienced gather contractors have to be used to gather an increased number of horses. Due to the magnitude of overpopulation, the AAEP and AVMA additionally support the strategies of permanent sterilization and unrestricted sale to stabilize horse and burro numbers in critical management areas. “Crisis” is the designation given to the situation by both government and private groups; action must be taken. All management tools carry certain risks. The risks of repeated capture of horses should be weighed against the risks of other management tools. The ultimate goal by all interested groups is healthy horses maintained on healthy rangelands with a minimal amount of human intervention. The AAEP and AVMA believe that all management strategies should be assessed with this goal in mind.

Email addresses to direct communications to:

AAEP: equinewelfareataaep [dot] org (equinewelfare[at]aaep[dot]org)
AVMA: animalwelfareatavma [dot] org (animalwelfare[at]avma[dot]org)