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Interior Department should not remove the ovaries of wild horses

Wild horses
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Wild horses bureau of land management department of interior

Today, the U.S. House of Representatives passed the Interior Appropriations bill — a massive piece of legislation that funds a wide range of government programs and agencies, including the National Park Service and the Environmental Protection Agency.

Every year, the Interior bill becomes a vehicle for all manner of controversial riders that impact our nation’s wildlife. This year was certainly no exception. But what’s new this cycle is a tucked-away provision that would adversely affect some of our most iconic and treasured animals: wild horses that embody a spirit of freedom for so many Americans.

{mosads}Under an amendment by Rep. Chris Stewart (R-Utah) — a longtime and vocal proponent of culling wild horses to reduce population size — the Department of the Interior’s Bureau of Land Management (which oversees much of the land these animals inhabit) could launch a mass surgical sterilization program for stallions and mares.


A diverse group of stakeholders recognizes the need to deal more effectively with wild horse populations on the range. But when it comes to managing these federally protected animals, it is important to implement viable and humane fertility control options that the American public can support. It is irresponsible for the federal government to use tax dollars for surgical sterilizations.

Stewart’s amendment ignores obvious humane fertility control options, such as porcine zona pellucida (PZP) — an immunocontraceptive vaccine that can be administered safely. Conversely, surgical sterilization entails a risky, stressful, painful, and highly invasive procedure on the animal.

Conducting ovariectomies (i.e., removing the ovaries of mares) on the range or in a holding pen is a complex and costly process. Trained medical professionals would need to conduct the surgery. 

In ideal circumstances, horses undergoing this procedure — which is normally performed to deal with an abnormality or to remove a malignant growth — would be put under general anesthesia and monitored carefully. Wild horses, by contrast, would likely receive local anesthesia. The reality is that these proposed surgical sterilizations would be conducted in a nonsterile environment, thereby increasing the risk of post-operative complications including infections.

In a 2013 report on improving wild horse management, the National Academies of Sciences stated that ovariectomies are “inadvisable for field application” due to the probability of “prolonged bleeding or peritoneal infection.” 

Whether the Bureau of Land Management has fully weighed the costs and feasibility of a mass surgical sterilization program is unclear. Any population control proposal should consider the following factors: pain relief, antibiotics to treat infections, the long-term health and behavioral effects of removing organs, the ability to provide individual care and attention, and the safe handling and transport of large wild animals.

For an agency that routinely warns lawmakers and the public that it lacks sufficient resources and funding to effectively manage wild horses and burros, the idea of bankrolling mass surgical sterilizations doesn’t make fiscal sense. If the Bureau of Land Management were to move forward with impractical mass sterilizations and the results fell short for whatever reason (costs, difficulty, complications), that failure could spur lawmakers to renew their push for the agency to resort to outright culling the herds to reduce numbers. 

Wild horses are protected by the Wild and Free-Roaming Horses and Burros Act of 1971, which established a policy of allowing these “living symbols … of the West” to thrive on public lands. This latest rider circumvents the law’s intent since mass permanent sterilizations would lead to nonreproducing herds and nonviable populations.

As lawmakers in the Senate and House work to reconcile their versions of the Interior bill in the coming weeks, they would do well to reject this misguided approach to herd management.

Joanna Grossman, Ph.D., is the equine protection manager at the Washington, D.C.-based Animal Welfare Institute.

Tags Chris Stewart Department of Interior Joanna Grossman wild horses wildlife

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