Healthy populations of animals in the wild are kept in check by limitations of available resources (food, water and shelter) and the complex interactions between predator and prey. Unfortunately, America's vast rangelands are fenced for livestock and encroached upon by human use, and development. Further, predator populations are under constant siege by this development, and from ranching, hunting, and poaching. The natural system of checks and balances the nature operates under now struggle to work in harmony.
At Return to Freedom, our goal is to take a solutions focused approach to minimize, and if possible eliminate, the need for costly and traumatic roundups, as well as save millions of tax dollars, while ensuring that natural selection and results in healthy genetic diversity of America’s free ranging wild horses and burros. We advocate for slowing growth rates, as opposed to stopping it all together or repeatedly removing wild horses and burros from the range. Our mission includes:
- Maintaining harem bands to allow natural social behaviors
- exploring minimally intrusive, safe and humane wild horse management that can be applied on the range
To that end, RTF had six herd management options:
- Option 1: No management (increasing population)
- Option 2: Adoption or sale (to address increasing population)
- Option 3: Permanent sterilization of stallions (permanent/affects behavior)
- Option 4: Permanent sterilization of mares (permanent/affects behavior)
- Option 5: Separation (permanent/affects behavior)
- Option 6: Contraception (reversible, allows natural social bands)
After examining all options, fertility control was selected at RTF as an appropriate approach: it allowed us to maintain a stabilized population while family bands lived together, it was sustainable, it was less invasive than other techniques, and it enables us to extrapolate our experience outward and participate in on-range wild horse and burro management discussions.
Education is a primary goal of Return to Freedom’s mission. Our sanctuary was created in 1998 not only as a model to explore solutions for wild horse and burro management that could be applied on the range (as an alternative to the capture, removal, and warehousing of wild horses and burros), but also as a venue to appreciate and observe natural horse behaviors. With an impressive array of research and peer-reviewed publications behind it, Native PZP was a proven effective and humane immuno-contraceptive vaccine, and it aligned with our mission. In 1999, RTF reached out to Dr. Jay Kirkpatrick, Director of The Science and Conservation Center in Billings, Montana. Under his guidance, RTF has been able to manage herd populations at the Sanctuary utilizing Native PZP — a non-hormonal, reversible fertility control vaccine, effective at slowing down reproductive growth rates in wild mammals. RTF became the fourth project in the world to use this method of fertility control on large numbers of equines and has had a 91-98% efficacy rate at the sanctuary.
Over many years of wildlife fertility control conferences, ideal parameters for effective and ethical fertility control vaccines were developed, which are met by PZP:
- High efficacy (at least 90%)
- Capable of administration via remote delivery
- Safe for pregnant animals
- Does not pass through food chain
- Limited or zero side effects
- Does not influence the social behavior of an animal
In order to allow our horses to live as natural a lifestyle as we can provide, wild horse bands at Return to Freedom are managed with Native PZP. This allows the natural hormone-driven movement and behaviors which are necessary for the horses’ well-being physically and emotionally.
Our early data, presented at the 2012 Wild Horse Symposium in Jackson Hole, WY, showed that RTF’s fertility control program had an efficacy rate of between 85-91%. In the years since then, we have achieved 98% efficacy. Currently, all fertile mares housed with band stallions are on fertility control.
Even if the BLM could administer the vaccine to every mare on federal lands, it would not be possible to zero out herds with this method. But it would be possible to begin stabilization of population numbers and to reduce reliance on round ups and warehousing of wild horses and burros. Unfortunately, BLM has been slow to implement meaningful levels of reversible fertility control, and has focused on permanent sterilization to achieve its desired population goals. We must continue to stay engaged and work as guardrails to a bureaucratic system that requires steady, thoughtful, respectful oversight and new improved methods for determining where and when we push, and where we work alongside.
Summary of PZP efficacy at RTF's Lompoc sanctuary
PZP myths and facts
Immunocontraception in Wild Horse Herds. First Edition, May 8, 2015.