June 09, 2015 2:00 am
The Bureau of Land Management used to round up more wild horses more frequently, even herding excess equines with helicopters. More recently, such gatherings are much smaller and gentler — more like dinner invitations.
BLM has been seeking public comment on a plan for the Pryor Mountain Wild Horse Range this fall. Horse specialists would set up portable panel pens at water sources, haul in feed and open the doors. Sometime after horses get used to walking in and out of the pen, the crew closes the doors.
Then they would be very choosy about which horses to corral pending adoption and which to keep on the range. The Pryor Mountain Wild Horse Range, south of Billings,Mont., on the Montana-Wyoming border, is managed to:
- Maintain a ratio between male and female.
- Maintain a core breeding population between 5 and 10 years old.
- Preserve characteristics of the Colonial Spanish Type horses.
- Preserve rare coloration.
- Prevent elimination of bloodlines.
The BLM proposes removing 25 horses, ages 1-3 years, this fall. The agency counted 167 horses recently, well over the range's established carrying capacity of 90-120. BLM said the present horse population is overgrazing areas of the range.
Such horse removals have become rarer, and it's expected that the fall operation will be one of the last in the Pryors. Wildlife managers have a great and effective tool for keeping the population at carrying capacity — without killing or removing any horses.
The tool is a contraceptive vaccine that was developed in Billings. Jay Kirkpatrick heads the Science & Conservation Center that produces doses of PZP (porcine zona pellucida) vaccine used by zoos and wildlife agencies across the nation and around the world.
Kirkpatrick recently recalled how he switched his research focus to wildlife contraception. It was in 1971 while he was teaching biology at Eastern Montana College. Two BLM horse management specialists, Ron Hall and Gene Nunn, came to his office and talked to him a few months after the Wild Free-Roaming Horses and Burros Act provided for the animals to be adopted. They asked: Can you stop wild horses from reproducing?
They expected that wild horse reproduction would outpace the supply of adoptive homes within 10 years. The horse experts were right.
Kirkpatrick accepted the challenge to develop a safe and effective means of reducing reproduction. The result of years of research is a vaccine, given annually as an injection to mares to prevent pregnancy.
A PZP vaccine for elephants is used at 20 game reserves in South Africa and for wild horses at 35 sites in the United States. About 200 zoos worldwide use the vaccine for 85 species. The Theodore Roosevelt National Park in North Dakota has been using vaccine with its herd.
The growth in the Pryor wild horse herd has been reduced by more than half with limited use of the vaccine, according to a BLM environmental assessment. Between 15 and 18 foals are expected this year.
"The Billings Field Office is excited to be on the cusp of nearly eliminating the need for wild horse removals due to the use of PZP," Jim Sparks, field manager, said in a March press release.
Most humane organizations and wild horse advocates endorse the contraceptive vaccine that has produced healthy populations and healthier range.
This wildlife management success story started right here in Billings and continues with the nonprofit Science & Conservation Center adjoining ZooMontana.
-- Billings (Mont.) Gazette
Originally published in the Bismark Tribune. View on Tribune website here.