Wild Horse and Burro Management

“Be it enacted by the Senate and Horse of Representatives of the United States of America in Congress assembled, The Congress finds and declares that wild free-roaming horses and burros are living symbols of the historic and pioneer spirit of


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“Be it enacted by the Senate and Horse of Representatives of the United States of America in Congress assembled, The Congress finds and declares that wild free-roaming horses and burros are living symbols of the historic and pioneer spirit of the West; that they contribute to the diversity of life forms within the Nation and enrich the lives of the American people; and that these horses and burros are fast disappearing from the American scene.”

These are the opening words of Public Law 92-195, The Wild Free-Roaming Horse and Burro Act of 1971, which established the protection, management, and control of wild, free-roaming horses and burros on public lands.1 To many Americans, these animals personify the unbridled spirit and vast expanse of the rangelands, mountains, and deserts of the Western United States.

The Bureau of Land Management (BLM) and the Forest Service are charged with managing wild horses and burros as an integral part of the natural ecosystem of public lands. The BLM has custodial responsibility for approximately 45,000 wild horses and burros living on more than 35 million acres throughout the western U.S. The BLM is presented with both the opportunities of managing a national symbol that holds a special place in the public’s heart and ideals, and the challenges of maintaining those ideals in a manner that achieves and maintains a thriving natural ecological balance on public lands.2

The management of wild horses and burros also presents the equine practitioner with opportunities and challenges. Veterinarians can partner with adopters during the transition of wild horses and burros to domesticated life by sharing their knowledge of equines and providing quality veterinary care. The challenges–and there are many–involve working with a wild animal still unsure of its relationship with humans, and adopters whose experiences with horses and burros might be limited.

This article will help horse owners understand how those equids came to be in wild horse herds–and thus in adoption programs–and the requirements imposed on an adopter for their care.

Horse-Saving History

During the 1950s in Nevada, Velma B. Johnson, later called Wild Horse Annie, became aware of the ruthless, indiscriminate manner in which wild horses were being gathered from rangelands. Ranchers, hunters, and “mustangers” had a major role in harvesting wild horses for commercial purposes. Wild Horse Annie led a grass-roots campaign, with mostly school children, that engaged the public in the issue.

In January 1959, Nevada Congressman Walter Baring introduced a bill prohibiting the use of motorized vehicles to hunt wild horses and burros on all public lands. The House of Representatives unanimously passed the bill, which became known as the “Wild Horse Annie Act.” The bill became Public Law 86-234 on Sept. 8, 1959. However, it did not include Annie’s recommendation that Congress initiate a program to protect, manage, and control wild horses and burros.3

Public interest and concern continued to mount, and in response members of the Senate and the House introduced a bill in the 92nd Congress to provide for the necessary management, protection, and control of wild horses and burros. The Senate unanimously passed the bill on June 19, 1971. After making some revisions and adding a few amendments, the House also passed the bill by a unanimous vote. Former President Richard M. Nixon signed the bill into law on Dec. 15, 1971. The new law became Public Law 92-195, The Wild Free-Roaming Horse and Burro Act of 1971.

Management Planning

The BLM manages wild horse and burros on the public rangelands consistent with its multiple-use mission, which takes into consideration natural resources such as wildlife and vegetation and uses for these resources such as livestock grazing and recreation. The primary responsibilities of the BLM, as dictated by law, are to protect, manage, and control wild horse and burro populations in a manner designed to achieve and maintain a thriving ecological balance.

Wild horses and burros are found in 213 herd management areas covering 35 million acres of public lands in Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, and Wyoming.2 Through intensive land use management planning efforts, the BLM determines where wild horses and burros will be managed, and the appropriate number of wild horses and burros that each herd management area can support.

By law, the BLM must limit its activities to manage wild horses and burros to the minimum feasible level necessary to achieve and maintain its objectives. During the planning process, the BLM actively solicits public input regarding management of the animals and their relationship to other rangeland uses. The public is able to participate in the planning process by providing information for analysis and comments on proposed decisions.

Through coordination with the public, the BLM also develops population management plans that set forth objectives–and tasks required to meet those objectives–including maintaining certain herd characteristics, adjusting the population of smaller herds to maintain genetic viability, and the use of fertility suppression agents.

Controlling Overpopulation

The BLM analyzes monitoring information to determine if the herds are healthy and if the animals are damaging rangelands within the herd management area. When analyses of these data indicate an overpopulation problem, the BLM develops plans detailing the procedures for gathering and removing a proportion of animals in a given herd management area.

Unchecked by natural predation and aided by high fertility and low mortality rates, wild horse and burro populations can double every four years. In response to this, the BLM has been a leader in supporting research to control wild horse reproduction. The BLM, through its contract research partners, has developed an immunocontraceptive vaccine capable of inhibiting pregnancy in mares for one year, and researchers are continuing work on a two-year version of the vaccine.4 The vaccine stimulates an immune response from the animal that results in the egg not being able to be fertilized. The vaccine is made by the research team and is currently only available for the support of research projects; it is also used in studies involving white-tailed deer.

The vaccine is only being used on an experimental basis, but has potential to be a safe and humane contraceptive agent to reduce fertility rates for large numbers of wild horses. However, current populations of wild horses and burros far exceed the land’s ability to support them, and contraceptive agents provide a tool that only slows population growth. In order to achieve an ecological balance between wild horses and burros and the land, the removal of large numbers of animals is required.

Round ’em Up!

There are approximately 45,000 wild horses and burros on lands administered by the BLM, while those lands can only support approximately 26,000 animals. In response to this large imbalance, a 10-year strategy was developed to reduce the number of wild horses and burros to within the appropriate management level.5 This strategy, begun in October 2000, will require the removal of 8,000-12,000 wild horses within the next few years. Upon achieving a balanced population within the herds, optimum numbers can be maintained by removing approximately 4,500 animals per year.

Wild horses and burros are gathered using either helicopter drive trapping or bait trapping. (Bait trapping lures animals into a set of corrals using water or feed. The method is generally used in hot, dry environments where feed or water are very limited, and can be very effective for capturing wild burros.) The animals are gathered, separated by age and sex, and a BLM wild horse and burro specialist decides which animals will be removed and which will be returned to the range. The selection is based on maintaining predefined age and sex ratios in the herd and a genetically viable (i.e., varied) herd. Population modeling is used to estimate the ratios that would best match what would occur in nature.

After removal, the BLM either places the animals into private care and maintenance through the adoption program or relocates animals determined to be unadoptable into long-term holding facilities. These are the only two options available to the BLM for addressing the disposition of animals removed from the range. The BLM is prohibited from humanely destroying healthy, unadoptable wild horses and burros.6

These Midwest holding facilities cover thousands of acres of pasture that allow geldings and mares to be separated.

Before being offered to the public for adoption, all wild horses and burros removed from the range are first held in one of the BLM’s adoption preparation facilities. There the animals are first handled by humans and receive their first veterinary care. Wild horses and burros on the range are free of some diseases that occur in domestic horses and burros; however, they are also naïve to many common domestic equine diseases. All animals are dewormed and receive basic equine vaccinations including equine encephalomyelitis, tetanus, influenza, equine viral rhinopneumonitis, Streptococcus equi, and regionally specific vaccinations as recommended by veterinarians. Animals are also treated for any physical injuries, and veterinary care is provided to all wild horses and burros throughout their time in BLM facilities.

Each animal is freeze-marked on the left side of the neck with an individual identification symbol (see “How to Read a Freeze Mark” on page 48). The BLM uses freeze marking with the International Alpha Angle System, which consists of a series of angles and alpha symbols, because it is a permanent, unalterable, and painless way to identify each horse or burro as an individual. The mark contains the Registering Organization (U.S. Government), year of birth, state of origin, and registration number.

In addition to the freeze mark, each animal is assigned an alpha-numeric signalment code, which is entered into the Wild Horse and Burro Information System database. This code allows the BLM to track the animal through the facilities to adoption, and to keep records on where and when the animal was captured and prepared for adoption. Health and transportation records, adoption information, and ownership status also are recorded in this database.

The stress of handling can create unique management challenges to safeguarding the health of wild horses and burros. In 1999, the BLM established a partnership with the United States Department of Agriculture’s Animal and Plant Health Inspection Service to provide the BLM with assistance in improving veterinary care and animal handling capabilities while also providing a resource to coordinate research related to the health and well-being of wild horses and burros.

Through this partnership, the BLM is working with researchers to address problems such as shipping stress and upper respiratory disease. The BLM is also partnering with researchers to study the unique hoof characteristics of wild horses. The aim is to benefit both the domestic and the wild horse by providing insight for veterinarians, farriers, and breeders into the effects of the environment, genetics, diet, and exercise on hoof shape and bone structure.

The Adoption Process

Once a veterinarian determines that a wild horse or burro is ready for adoption, the animal is offered to the public at one of several adoption centers around the country (visit www.wildhorseandburro. blm.gov for more information). The process of adopting a wild horse or burro involves three parts. First, the potential adopter must apply for adoption eligibility by meeting a specific set of requirements, including:

  • At least 18 years of age (Parents or guardians may adopt a wild horse or burro and allow younger family members to care for the animal);
  • No prior conviction for inhumane treatment of animals or for violations of the Wild Free-Roaming Horse and Burro Act;
  • Demonstration that they have adequate equine feed, water, and facilities to provide humane care for the number of animals requested; and,
  • Demonstration that they can provide a home for the adopted animal in the United States.7

Second, once approved for adoption, the adopter signs a Private Maintenance Care Agreement with the BLM. Under this agreement, the adopter assumes all responsibility for the care of the adopted animal(s) for a period of one year. This responsibility includes veterinary and farrier care. In addition, the adopter must testify that he/she has no intention of commercially exploiting the adopted animal, including selling the animal for slaughter.

During the first adopted year, the wild horse or burro remains the property of the United States government, and the BLM or its agents might conduct compliance visits to ensure proper care is being provided. At a compliance visit, the physical condition of the animal is evaluated8 and an inspection is conducted to ensure that the facility requirements are being met (including space and fencing requirements as well as adequate shelter, sanitation, and drainage). Food and water sources are examined, and health care is also discussed.

It is during this phase of the adoption that most equine practitioners will first come in contact with the wild horse or burro and the adopter. A review by the BLM showed that the majority of adopters had horses prior to adopting their wild horse or burro.9 For others, however, this was their first experience as a horse owner. Regardless of their previous experience, caring for an untamed wild horse or burro requires a different approach than caring for a typical domestic animal. In addition to providing high-quality health care, the equine practitioner has the opportunity to help the adopter develop a safe and positive relationship with their new animal. Often the private practitioner is the closest resource for these new owners’ questions regarding health, nutrition, and general husbandry practices. The majority of problems the BLM encounters relative to the private care of an adopted wild horse or burro are with basic animal husbandry and health care.

Although gentling before adoption is not a requirement, it is strongly encouraged. The BLM is taking an active role in creating programs to gentle some horses and burros before adoption. Examples of these efforts include the prison programs in Colorado, Wyoming, and California; more recently, arrangements have been made with private trainers such as Steve Mantle in Wheatland, Wyo. The programs are designed to increase successful wild horse adoptions, and are receiving recognition in the popular press as a way of improving marketing and adoption efficiency.10 Taxpayers, adopters, and the horses benefit from these efforts.

There are also resources available for adopters after they bring home their wild horse or burro, such as the list of professional trainers who work with wild horses or burros on the BLM web site at www. wildhorseandburro.blm.gov.a The BLM is also partnering with the public to provide post-adoption assistance in caring for newly adopted wild horses and burros. The Wild Horse and Burro Mentoring program was initiated in 2000 to link members of the public experienced with wild horses and burros to new adopters. The mentors offer assistance in finding veterinarians and farriers as well as animal care and gentling.

The BLM holds a workshop each year to provide mentors the opportunity to learn and refine their gentling skills with experienced trainers. There are also several independent wild horse and burro mentor organizations, the largest of which is Least Resistance Training Concepts, Inc., in Knightsen, Calif.b

Occasionally, someone is concerned about the care another is giving an adopted wild horse or burro. The BLM immediately responds to all complaints–the goal is successful adoption, and they try to work with the adopter to correct the problems if appropriate. If it is not appropriate to leave the animal with the adopter, the animal will be repossessed. In extreme cases, the adopter will be charged with abuse and violation of the Wild Free-Roaming Horse and Burro Act of 1971.

It can be a challenge for the equine practitioner to provide veterinary care to a wild horse or burro. This challenge can also be an opportunity to learn, share knowledge and expertise, and help a new client build a positive relationship with the new horse. Qualified volunteers are needed to present horse health care seminars at adoptions and provide contacts for the BLM to give to new adopters. Veterinarians building partnerships with adopters increases the potential for successful adoptions.

The veterinarians and other professionals who work with the Wild Horse and Burro program are proud of advances made in recent years. These programs are critical to ensure the humane care and treatment of wild horses and burros. The goal is to preserve an American symbol while learning more about wild horses and burros so we can safeguard their health and well-being, and better understand their domestic cousins.


Bureau of Land Management National Wild Horse and Burro Program. www.wildhorseandburro.blm.gov, 1-866-4MUSTANGS.


a BLM website: www.wildhorseandburro.blm.gov/trainerwhb.html

b LRTC Wild Horse Mentors, P.O. Box 648, Knightsen, CA 94548. www.mentors.org


1. Public Law 92-195. 1971. The Wild Free-Roaming Horse and Burro Act of 1971.

2. Wild Horse and Burro End of Year Report, Bureau of Land Management, United States Department of the Interior, 2000.

3. Public Law 86-234. 1959. Wild Horse Annie Act.

4. Turner, JW; Liu, IKM; Flanagan, DR; et al. 2001. Immunocontraception in Feral Horses: One Inoculation Provides On Year of Infertility. Journal of Wildlife Management 65(2): 235-241.

5. Bureau of Land Management. Living Legends in Balance With the Land Strategy. United States Department of the Interior, 2000.

6. Public Law 106-291. 2001. The FY 2001 Interior and Related Agencies Appropriations Bill.

7. 43 CFR 4750.3-2. 2000. Qualification
Standards for Private Maintenance. U.S. Government Printing Office. Washington: 2000.

8. Henneke, DR; Potter, GD; Kreider, JL; et al. Relationship between condition score, physical measurements and body fat percentage in mares. Equine Veterinary Journal 1983; 15:371-372.

9. Bureau of Land Management. Prospective Adopter’s Perception of the Bureau of Land Management’s Wild Horse and Burro Program. United States Department of the Interior, 2000.

10. Vorhes, G. Starter Kit Mustangs: A wild horse adoption provides a Bryan Neubert clinic to assist new owners. Western Horseman 2001; 66:168-176

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Written by:

Albert Kane, DVM, MPVM, PhD, is a Post-Doctoral Fellow in Biomedical Sciences in the College of Veterinary Medicine at Colorado State University

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