Pryor Mountains Mustangs Benefit from Birth Control Vaccine

Editor's Note: While a recent newcomer to the wild horse advocacy scene has criticized the use of birth control to humanely manage wild horses, experts and long-time advocates assert that the PZP vaccine is effective in preventing helicopter roundups and eliminating the removal of wild horses from the range.

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Protestors claim the BLM office in Montana is attempting to eradicate the state's last herd of wild horses, residing in the Pryor Mountains of Montana and Wyoming. Recently, the group marched into the Billings Field office, demanding the agency abandon plans to round up horses and use birth control on the mares.

The Pryor Mountains are home to the internationally famous “Cloud” stallion, a pale palomino wild horse whose family is one of several that inhabit the Pryors. Other wild horse herds exist in northern Wyoming, with commercial tours available to see the McCullough Peaks herd near Cody. The mares in that herd have been darted with a contraceptive called PZP for years, and local wild horse advocates are pleased with the results.

Warren Murphy, president of the board of Friends of a Legacy (FOAL), stated, “Presently, I think we’re about 140 horses. We’ve not had a roundup there by helicopter for many years. The horses love it out there. People love to see them out there.”

However, Friends of Animals protested the proposed use of PZP at the Billings BLM Field office. They also opposed the agency's plans to round up the horses and remove 25 of them for adoption. FOA Campaigns Director Edita Birnkrant expressed concerns that this could decimate the herd.

BLM spokesman Al Nash explained that the agency aims to protect the herd, stating that helicopters will not be used for what he calls “the gather.”

Nash elaborated, “Our approach to gathering horses is to have a fenced-in area, put out water and feed. They walk in, we select a small group, and release the rest.”

Due to the popularity of the “Cloud” group, Nash noted that the BLM’s Pryor horses are always adopted.

“There’s only so much landscape, and there’s only so much forage. Our job is to manage for a healthy wild horse herd and a healthy range.”

Birnkrant of Friends of Animals pointed out that wild horses are limited to only 25,000 acres in the Pryors and expressed concerns about the use of the fertility drug PZP.

Dr. Jay Kirkpatrick, whose non-profit organization produces the drug in Billings, stated that it is used to control horse, bison, and elephant populations worldwide, including in many zoos.

Kirkpatrick said, “We have wild horse ranges that have reduced or eliminated the need to round up and remove wild horses on the range.”

He argued that it is cruel not to control the Pryor population, as the animals would otherwise face starvation.

“We fenced them. They can’t roam three hundred miles to meet environmental challenges like drought or bad winters. They’re trapped. I watched one half of the Pryor Mountain herd die in 1977 four hundred yards from where they could have survived. But, they couldn’t get there because of the fence.”

Kirkpatrick noted that the McCullough Peaks herd near Cody has benefited from the BLM’s PZP treatments.

He said, “They’re into their fourth year. They reached zero population growth in three years. McCullough Peaks is one of the most spectacular and successful management programs we have out here.” Kirkpatrick added that several economic studies show the contraceptive approach can save taxpayers millions.

Originally published by Wyoming Public Media.