36+ Wild Horse Advocacy Groups Press BLM for Increased Use of Humane Fertility Control

Newsdate: Thu 02 June 2016 – 9:12 am

More than three dozen wild horse advocacy, rescue and humane organizations, representing more than 10 million citizens, stand united in calling on the U.S. Bureau of Land Management to make greater use of the humane fertility control vaccine PZP as a way to stave off its “billion-dollar” fiscal crisis caused by wild horse roundups in the American West.

PZP vaccine - Best way to stave off BLM’s pending “billion-dollar” fiscal crisis

PZP vaccine - Best way to stave off BLM’s pending “billion-dollar” fiscal crisis

Already, 70 percent of the BLM’s $80 million Wild Horse and Burro Program budget is spent on roundups and removals, while less than 1 percent of that amount is spent on long available, humane and effective fertility control.
© 2016 by American Heritage Mustang Foundation

The organizations contend that the PZP vaccine is a cost-effective alternative to costly roundups and removals of wild horses from the range.

The call for greater use of PZP comes on the heels of a recent admission by BLM Director Neil Kornze that the current system of roundups is failing. In fact, according to Kornze, the BLM’s  policy of rounding up and removing, and stockpiling wild horses in holding facilities is leading up to a $1 billion crisis – the amount U.S. taxpayers will ultimately pay to warehouse thousands of wild horses for decades after the BLM has removed them from the range.

Already, 70 percent of the BLM’s $80 million Wild Horse and Burro Program budget is spent on roundups and removals, while less than 1 percent of that amount is spent on long available, humane and effective fertility control.

Groups supportive of the use of the PZP vaccine for humane wild horse management include the:

  • Alliance of Wild Horse Advocates
  • American Society for the Prevention of Cruelty to Animals 
  • American Wild Horse Preservation Campaign
  • Animal Legal Defense Fund
  • Animals Voice
  • Animal Welfare Institute 
  • Black Hills Wild Horse Sanctuary
  • Center for Animal Protection and Education
  • Citizens Against Equine Slaughter
  • The Cloud Foundation
  • Corolla Wild Horse Fund
  • Friends of a Legacy
  • Front Range Equine Rescue
  • Habitat for Horses
  • Hidden Valley Wild Horse Protection Fund
  • Horses for Life Foundation
  • Humane Society of the United States
  • Jicarilla Mustang Heritage Alliance
  • Least Resistance Training Concepts
  • Lifesavers Wild Horse Rescue
  • Montgomery Creek Ranch
  • National Mustang Association, Colorado Chapter
  • Oregon Wild Horse & Burro Association
  • Photographers for the Preservation of Wild Horses and Burros
  • Pine Nut Wild Horse Advocates
  • Respect 4 Horses
  • Return to Freedom Wild Horse Sanctuary and Preservation
  • Salt River Wild Horse Management Group
  • Serengeti Foundation
  • Southern Sun Farm Sanctuary
  • Steadfast Steeds
  • Virginia Range Wildlife Protection Association
  • Wild Equid League (Colorado)
  • Wild Horses of America Foundation
  • Wild Horse Connection
  • Wild Horse Education
  • Wild Horse Observers Association
  • Wild Horse Preservation League

In the last seven years alone, BLM has removed more than 40,000 wild horses from public lands. The agency now stockpiles as many wild horses in captivity as remain free on the range.

The National Academy of Sciences (NAS) recommended the use of PZP in its 2013 study “Using Science to Improve the BLM Wild Horse and Burro Program,” stating it is “a more affordable option than continuing to remove horses to long-term holding facilities.”

The NAS study also noted that roundups and removals of wild horses are actually responsible for “facilitating high rates of population growth on the range.”

The NAS added that “removals are likely to keep the population at a size that maximizes population growth rates, which in turn maximizes the number of animals that must be removed through holding facilities.”

PZP is an immunocontraceptive vaccine. It works with a mare’s immune system to produce antibodies that block sperm receptor sites on the zona pellucida, a thin membrane surrounding the ovum.

Because it is non-hormonal, PZP does not:

  • Affect the endocrine system or natural behavior of horses.
  • Create negative health side effects.
  • Enter the food chain or harm other wildlife.

The vaccine is reversible and is administered with a simple dart.

PZP has been used for more than 25 years in the wild horses on the Assateague Island National Seashore in Maryland. In that time, the herd has been brought to more sustainable numbers and the overall health of horses as a result has improved substantially. In 1990, few horses on Assateague lived past 15 years.Now, many are living 30 years or more. And, because PZP is not permanent, the National Park Service managers can closely control the herd’s population, allowing for increased births as appropriate.

Management programs with PZP also have helped curtail and even end roundups in wild horse  management areas in the West, such as the Pryor Mountains on the Montana/Wyoming border, McCullough Peaks in Wyoming and Spring Creek Basin and Little Book Cliffs in Colorado.

In Colorado’s Spring Creek Basin, no mustangs have been removed since 2011, thanks to a BLM-facilitated public/private partnership for humane management of this herd utilizing the PZP vaccine.

In addition, the BLM has committed to bait trapping if, in the future, the removal of some mustangs is necessary to maintain range health. Bait trapping is a far less traumatic capture method than helicopter roundups.

A PZP project on the McCullough Peaks range in Wyoming, meanwhile, helped the wild horse population there achieve zero population growth within three years.

Increased use of PZP and a reduction in roundups and removals would also be a boon to U.S. taxpayers, helping to curtail the $1 billion crisis created by the BLM.

The public now spends about $49,000 for each mustang that is removed from the range and not adopted. PZP, meanwhile, costs about $27 per darted horse per year.

One economic model published in the Journal of Zoo and Wildlife Medicine (Deseve, Boyles Griffin, 2011) demonstrated that BLM could save $8 million over 12 years by using PZP in one herd management area alone. Multiply that by 179 HMAs and the cost-savings reach the hundreds of millions.


  • Using Science to Improve the BLM Wild Horse and Burro Program
  • Q&A on PZP Fertility Control
  • The Science and Conservation Center
  • Myths and Facts: Native Porcine Zona Pellucida (PZP)
  • Information: Animal Fertility Control Vaccine

About the Author

Flossie Sellers

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As an animal lover since childhood, Flossie was delighted when Mark, the CEO and developer of EquiMed asked her to join his team of contributors.

She enrolled in My Horse University at Michigan State and completed a number of courses in everything related to horse health, nutrition, diseases and conditions, medications, hoof and dental care, barn safety, and first aid.

Staying up-to-date on the latest developments in horse care and equine health is now a habit, and she enjoys sharing a wealth of information with horse owners everywhere.