Wild Horses in Theodore Roosevelt National Park: Health and Reproduction Insights

Wild Horses: Health and Reproduction in Theodore Roosevelt National ParkWild Horses: Health and Reproduction in Theodore Roosevelt National Park

Wild horses in Theodore Roosevelt National Park are thriving, with a 90 percent pregnancy rate among mares. While this indicates robust health, it also presents challenges in managing the population through roundups and auctions.

FRYBURG — Jason Bruemmer, a veterinarian and researcher, examined mares with names like “Little Brother’s Girl” and “Cheyenne.” He reported that the mares among the wild horses in Theodore Roosevelt National Park have a 90 percent pregnancy rate. The good news is that they are spectacularly healthy, as are the stallions. However, the rapid reproduction means another horse roundup and auction probably can’t be avoided.

The park roundup was in its third day Tuesday, and 150 of the park’s 211 horses had been driven by helicopter into the corral and handling facilities on the park’s east side. The handling and sorting process was quiet. Human voices were muted, and a new hydraulic chute minimized the clanging and whinnying sounds of frightened horses in close captivity.

By afternoon, stock trailers were loaded with the first of the 100 or so wild horses that will forever leave the park and be sold Saturday at Wishek Livestock. The auction has already attracted some serious money to buy and transport three dozen or so of the horses to an East Coast Legacy Mustang sanctuary, hopefully preventing any from going to a slaughter barn.

In 2009, the last time the park sold its wild horses, about 10 percent were sold for slaughter. The park hopes to avoid future roundups, or minimize them, by continuing a contraceptive vaccine program that started that same year.

Enter Bruemmer — a cheerful veterinarian and researcher with Colorado State University at Fort Collins, which is partnering with the park in the contraceptive program. This year, the 26 mares vaccinated in 2009 will get a booster, and another 10 will get one for the first time. Bruemmer said it’s hoped the booster will make the contraceptive last longer.

“The pregnancy rate is proof that the contraceptive agents are really needed. It’s not a permanent fix — time reverses the vaccine. We want to see if the booster makes it work better,” he said.

Maggie Bauer, a Colorado State researcher, has spent three years checking every week on all the vaccinated mares and the 26 mares that were not vaccinated in a blind study. Bruemmer said previously, the only way to know if the vaccinated mares were pregnant was to see if they foaled, not always possible if the foal died or fell prey to a mountain lion.

Researchers have since learned they can detect pregnancy hormones in droppings. Now, with samples collected during the roundup, they want to find out how much they can learn about the fetus itself, particularly how far along it is in an 11-month gestation cycle, he said.

The project has major implications beyond the park. “This could be large scale and lead to a declining population of wild horses. Ideally, it could eliminate roundups,” Bauer said.

Meantime, the park’s roundup is well underway and should conclude Thursday with the final delivery of the horses to Wishek. Marylu Weber, who works with the park to identify the horses in a North Dakota Badlands Horse Registry, helped handlers keep track of which horses were to be sold and labeled with a yellow sticker on their rump and which would be returned to their familiar Badlands.

She said the horses are healthy and of “good flesh.” Few people spend as much time with the wild horses as she does, naming them and keeping track of their lineage. “We’re hoping and praying there are a lot of good buyers,” she said.

The idea is to help educate buyers about the skills and patience needed to train wild horses, or find others willing to donate money to keep them from being slaughtered in Mexico or Canada.

Originally Posted By The Bismarck Tribune

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