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Wild horses gather in a canyon north of Grand Junction in this May, 1, 2006, file photo. (William Woody, Special to The Colorado Sun)

Researchers at Colorado State University’s veterinary school plan to help the federal Bureau of Land Management sterilize wild horses with a rarely used procedure that involves removing the mares’ ovaries.

The proposal, now in a 30-day public comment period, is kicking up a passionate protest from wild-horse advocates who say the surgery is barbaric, will traumatize the mares and could lead to infection and excessive bleeding.

CSU declined to comment, but its application to the Institutional Animal Care and Use Committee — which approves research involving animal testing — described how scientists will perform ovariectomies on wild mares in Oregon after they are rounded up by helicopter, sedated and placed in padded chutes.

The history: Plans for a similar program dropped after protests, legal challenges

The BLM’s latest plan to curb the wild horse population is similar to a 2016 proposal in collaboration with Oregon State University’s veterinary school. The federal agency dropped those plans in September 2016 after protests and legal challenges from wild horse lovers, mainly a claim that OSU’s ban on public observation of the research was a violation of the First Amendment.

In the weeks prior, the university had been inundated with phone calls, emails and campus protest.

“Literally, one morning four of us received each about 4,000 to 6,000 emails,” said Steve Clark, vice president for university relations at OSU in Corvallis. “By and far, well more than three-quarters came from states outside of Oregon.”

The federal government’s Wild Horse and Burro Program allows for public observation of horse roundups and birth-control measures, which so far have included a drug injected by dart.

The problem: Birth control for a wild horse population three times larger than “appropriate”

The BLM estimates there are nearly 82,000 wild horses and burros in 10 Western states, including 1,700 in Colorado. This is more than three times as many as the federal agency says is appropriate for the forage and water resources on public lands that also are used by wildlife and livestock.

Herds can double in size every four years. The overpopulation can cause wild horses and burros to starve to death or move onto private land and near highways in search of food and water, according to the agency, which spends more than $80 million annually on the management program.

To cut down on reproduction, the BLM uses two versions of a vaccine called PZP — one injected by hand at close range after the wild mares have been rounded up and another that is injectable by dart within 50 yards.

The problem is the vaccines last only one or two years, which requires rounding up mares several times throughout their lifetime, said Tara Thissell, a BLM public affairs specialist in Oregon. Research into longer-lasting vaccines is ongoing.

The horses are roaming on hundreds of thousands of acres of remote, roadless land, making it difficult to reach them. Also, the federal agency does not have enough staff dedicated to each herd to perform annual birth-control injections, she said.

“The less we have to handle and move the animals, the better,” Thissell said. The agency wants to know whether permanent sterilization is a viable option, she said.

The procedure: A century-old spaying technique that removes ovaries with a wire loop

The spay research first proposed with OSU and now CSU is the result of a 2014 federal request for proposals from universities. The National Academy of Sciences reviewed the wild horse management program in 2013, finding a lack of long-term solutions to control the population. That review, however, noted that the possibility of “prolonged bleeding” or infection after an ovariectomy made the procedure “inadvisable for field application,” a line often repeated by wild-horse advocates opposed to the spay proposal.

The proposal, outlined in BLM and CSU documents, says the study will include 200 horses, half in a control group and half in the study group that receives sterilization. An estimated 30 horses in the study group will undergo the spay procedure, which involves a 1- to 3-centimeter internal vaginal incision that allows a surgeon to reach the horse’s abdomen by hand. The surgeon injects pain medication into the horses’ ovaries before each ovary is crushed and removed using a chain ecraseur, an instrument with a wire loop similar to a chain on one end.

“While the surgical field may not be entirely sterile, all reasonable steps will be taken to ensure that it is disinfected,” the application says. The horses “will be deeply sedated” but not completely anesthetized.

“This is all done internally,” Thissell said. “There is no external incision. There may be some misunderstanding on what this is actually going to look like.”

Researchers plan to observe the mares in the facility for about seven days after surgery before they are returned to the wild. They would continue to study the herds for three years, including population size, behavioral changes and how sterilization might affect a mare’s place in a band, a social unit that includes a dominant stallion.

In addition to the 30 sterilized mares returned to the range, surgeons would remove the ovaries of about 70 other wild mares that would go up for adoption after an observation period, according to federal documents.

The cost of each 15-minute surgery is about $300, less than one dose of the birth control injected by dart.

The first documentation of an equine ovary removal dates back to the early 1900s, though the surgery is rare and typically only performed on mares with ovarian tumors and in some cases to calm their behavior.

Similar research is “very limited,” the BLM’s Thissell said, noting a prior study on horses at Sheldon National Wildlife Refuge on the border of Nevada and Oregon. The mortality rate in that study was less than 2 percent, she said.

Observation allowed, but no cameras or recording devices

Oregon State’s interest in banning observation of the sterilization research was for the safety of the horses, the university’s Clark said, noting that if the area became a spectacle, “it may be difficult to ensure that.”

The current plan calls for allowing up to five observers at a time but would require them to give up their cellphones, cameras and recording devices in accordance with CSU policy.

CSU researchers, in their application, said the study “will advance knowledge of the behavior and ecology of wild horses, and it will be good for society in ensuring that this cultural heritage remains sustainable.”

Wild-horse advocates, however, couldn’t see it more differently.

Carol Walker, director of field documentation for the Wild Horse Freedom Federation, called the procedure “horrific” and said she was offended CSU’s respected vet school would participate.

“I’m just appalled that they would be involved in this,” said Walker, who lives in Lyons and has taken two of her own horses to CSU, one for surgery and another for a rattlesnake bite.

“These are wild mares that are already panicked about being captured,” she said. “A surgeon sticks his hand in the vaginal cavity and rips her ovaries out.”

What’s next: Public comment schedule, BLM decisions

So far, the proposed research has received little publicity. But Walker and others said they are planning to make noise, including a letter-writing campaign timed for when CSU students arrive on campus next month. Public comment on the proposal closes this week, and the BLM plans to announce a decision in mid-August. 

If approved, the study would begin in October.

The BLM is keeping the names of the veterinary surgeons confidential under federal privacy laws.

Gayle Hunt, a wild-horse advocate in Oregon, said the 500- to 700-horse herd targeted for the research, the Warm Springs herd, is known for its Appaloosas, horses with colorful, spotted coats of gray, black and brown. They roam on barren, treeless land in central Oregon, among sagebrush and mesas, antelope and coyotes.

“I can’t believe they are trying this again after we shut them down in 2016,” Hunt said. “They should have gotten the hint.”

This story first appeared in The Colorado Sun’s newsletter, The Sunriser. You can subscribe here:

Jen is a co-founder and reporter at The Sun, where she writes about mental health, child welfare and social justice issues.

Her first journalism job was at The Hungry Horse News in her home state of Montana, before moving on to reporting jobs in Texas and Oklahoma. She worked for 13 years at The Denver Post, including several years on the investigative projects team, before helping create The Sun in 2018.

Jen is a graduate of the University of Montana and loves hiking, skiing and watching her kids' sports.

Email: Twitter: @jenbrowncolo