Park's Wild Horses: A Birth Control Experiment

Exploring Birth Control for Wild Horses

Theodore Roosevelt National Park is the site of an innovative experiment in wild horse population control. Led by Dan Baker, a research biologist at Colorado State University, this program aims to manage the expanding wild horse herd through contraception.

Waiting for Results

Within a month, Baker will know if his efforts have implications beyond this singular herd. The samples are in, and tests will soon reveal the results. "It’s totally unknown. It could be anything between no effects all the way to permanent sterilization," Baker said.

If successful, this method could control the park's wild horse herd and potentially thousands of wild horses on Bureau of Land Management land. It might also help manage wild dog populations in Third World countries or suppress fertility in domestic animals.

Badlands Lab

Baker's work began in 2009, using the park as a natural laboratory. During a wild horse roundup, 28 horses were vaccinated with GonaCon, a vaccine previously used in captive animals. The initial results were poor, but further research revealed that parasite loads might have affected the horses' immune responses.

Last year, the same mares were revaccinated to see if a booster would improve contraception. Volunteers collected fecal samples to measure estradiol levels, which indicate pregnancy. "If it’s 10 nanograms per gram, they’re not pregnant. If it’s 100, they are," Baker explained.

Park's Perspective

Blake McCann, the park's wildlife biologist, hopes the revaccination works to reduce the need for controversial helicopter roundups. If successful, it could allow for less traumatic management practices, such as corral trapping, to maintain the herd size within the ideal range of 40 to 90 horses.

McCann plans to conduct a corral trap this year to manage the 142 wild horses currently in the park. "I don’t want to get to 200 again and do another helicopter roundup," he said. He hopes Baker's work will provide a viable tool for managing the herd sustainably.

Originally Posted By Bismarck Tribune