Concerns over the population of wild horses and burros continues in many western states and with spring time foaling season taking place in many areas, the concern for growth in the population of wild horses gains the attention of concerned groups, both advocates for the wild horses and cattle grazing associations hoping to gain full access to public grazing lands.
Wild horses at BLM feeding station
Management issues of wild horses and burros range from the effects of rapid population growth on habitat to ensuring healthy populations for the future.
© 2015 by Peter Schmalzer
Advocates for maintaining the herds of wild horses on public lands work to promote adoption of any excess population of horses and to maintain the rights of the wild horses to roam freely.
The normal breeding period for wild horses and burros varies with location, but usually runs from March through September each year and peaks around mid to late June. The peak of foaling season for wild horses in has been documented to begin during April and hitting its peak around June 1, each year.
Management of Americaâs wild horses and burros is a daunting task. Through its national National Wild Horse and Burro Program, the BLM manages about 40,000 wild horses and 5,500 wild burros roaming in 179 herd management areas, comprising almost 32 million acres in 10 western states.
Management issues range from the effects of rapid population growth on habitat to ensuring healthy populations for the future. Largely unchecked by natural predators, it us estimated that wild horse populations grow at rates of 18â25 percent per year. According to those concerned about over-population of wild horses, this unregulated growth can overtax vegetation and affect herd health as well as native wildlife populations.
In 1971, the U.S. Congress passed The Wild Free-Roaming Horses and Burros Act in an effort to protect, manage, and control wild horses and burros on public lands. This legislation declared these wild animal populations to be "living symbols of the historic and pioneer spirit of the West."
At that time, wild horses on open ranges were fast disappearing; often considered pests, they were frequently slaughtered and sold to the horsemeat industry.
Today, the protected wild horse population is growing rapidly, which has caused new concerns. Herd sizes, if left unchecked, can double every four years. There is now concern that overabundant free-range wild horses are altering natural plant communities and reducing forage for native wildlife and livestock.
Land management agencies periodically round up wild horses to adopt out or sell. Many horses are housed in long-term holding pastures.
Fertility control has been used with moderate success to manage some wild horse herds, but the current method is effective only a short time and can cause undesirable side effects.
The Morris Animal Foundationâfunded researchers at Colorado State University recently completed a three-year research project to evaluate an alternative method of fertility control in wild mares, a gonadotropin-releasing hormone contraceptive vaccine.
The vaccine proved safe, caused few side effects, and was about 50 percent effective in reducing foaling rates over a two-year period. This was an improvement over the previous method, but still not ideal. In addition, three years after injection, 95 percent of the mares had regained normal fertility, meaning repeat vaccinations would be necessary.
The Colorado State University team has been giving booster shots to the previously vaccinated mares to measure the long-term effects of re-immunization. The 2015 foaling season data will gauge the success of these current research efforts.