LAMONT -- The horses moved uneasily, jostling each other, as the men approached the pen.
They threw their heads, springing into quick bucks as the men entered, and fleeing as far away as the fencing allowed.
Many of the horses had never been touched by humans.
The horses retreated from the man waving his arms, suddenly finding themselves in the confines of a chute too narrow in which to turn around, other horses crowding in front and behind.
Some kicked and shook their manes until they found themselves in a small enclosed box. Windows in the box opened. A quick whir of a razor left small patches for branding. Then two quick thrusts, one from a hand-held syringe and another from a larger jab stick wielded by wild horse specialist Scott Fluer, and the chute doors opened. Bureau of Land Management employees then waited for the next mare to enter the box, receive her shot and finish the agency's newest method of managing wild horses: birth control.
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The Wyoming roundup is serving as one of the BLM's national pilot sites. BLM Wyoming staff see the birth-control treatment as the future of managing the animals and offering a solution that will appease the public.
Lamont is, even by Wyoming standards, in the middle of nowhere, a dot on the map in the south-central part of the state signaling a turn off U.S. Highway 287 to Bairoil.
Just off the highway, the BLM built temporary holding pens for wild horses gathered in the Red Desert Herd Management Area. The gathering covers 750,000 acres, is home to about 1,400 wild horses in 16 herds and is also the site of a national test program to gauge the impact of birth control on the herds' populations.
About 800 wild horses will be gathered this year to be sent for adoption. The rest of the mares, about 200, will get a dose of birth control before being set free.
A camper sat near the pens. Inside, Fluer set up a mini science lab.
Scattered on the small dining table were syringes and plungers that shook when people moved around the camper.
Through the window, the horses waited in the pens.
Fluer works out of the BLM office in Lander. He is one of nine people in the United States trained in preparing and administering porcine zona pellucida, or PZP.
He grew up on a ranch near Livingston, Mont., and has always been around horses. He now owns nine horses, five of them wild. When a chance for training in PZP came up, Fluer headed to Reno, Nev., to meet the doctor who created the drug, and to learn how to mix and administer it.
PZP is a protein-based birth control that causes an immune system response, preventing horses from getting pregnant. Horses that receive the injection while already pregnant will still carry to term and be able to nurse normally. They just won't get pregnant again, Fluer said.
Fluer plans to give the shot to all mares 2 years old and older that are gathered from the Red Desert.
During a gather, about 80 percent of the area's horses are rounded up. The other 20 percent won't receive the shot and will be left to reproduce normally, Fluer said.
Every other year the mares will receive a booster shot. Research is already under way on an injection that will last four years, but it isn't expected to be ready for several more years, he said.
Fluer expected to treat about 200 horses with PZP during the Red Desert Herd Management gather. On Oct. 20 he prepared shots for 24 mares, with eight receiving boosters and 16 receiving PZP for the first time.
Each shot costs about $350, not including the cost of rounding up the animals, he said.
The shot is intramuscular, meaning Fluer doesn't have to find a vein to administer it. The goal is to keep the process as low-stress as possible. Horses are gathered, taken to a temporary holding area, like Lamont, and run through chutes. Each horse in the chute is quickly shaved, hydrogen-branded with an HB, the registered brand of the BLM, and given the shot and a pellet with a jab stick. They then bolt into a truck, which will take them back to the range for release. All of this usually happens within 24 hours of capture, Fluer said.
The Red Desert area project so far seems to be working. The herd management area generally had a reproduction rate of 20 to 25 percent, Fluer said. Since the drug's introduction in 2006, the rate has been 10 to 14 percent.
Ideally, the reproduction rate for the herd would be 10 to 12 percent, Fluer said. And the population would range between 480 and 724 horses.
There are now about 38,500 wild horses and burros in the United States, said Tom Gorey, a spokesman with the BLM in Washington, D.C. The ideal national population level is 26,600, he said.
A new management plan, still in the process of finalization, will cut the number of horses removed from about 10,000 to 7,600 a year for at least three years, Gorey said.
During those three years, the BLM will suppress population growth with a combination of fertility control using PZP and releasing gelded stallions. It also will try to skew the male-female ration on the range to 60-40, so that there are fewer females that can get pregnant.
Since the use of PZP started in 2004, about 2,800 mares have received the vaccine, Gorey said. It is being used in 79 of 179 herd management areas in 10 Western states, he said. Results have been mixed. A big issue is logistics in large herd management areas, he said.
"We don't regard it as a miracle drug, but we are committed to testing it and using it as widely as we can," he said. "We're not on the threshold of being able to turn everything around by means of fertility control. It shows promise, but it still hasn't proven itself yet."
In the Red Desert Herd Management Area, the BLM is optimistic. This year, the BLM will gather about 100 fewer horses than originally planned because of the smaller population, said Sarah Beckwith, a BLM spokeswoman. Officials think the lower numbers are the result of the first doses of birth control.
BLM officials plan to gather about 1,140 wild horses in the Red Desert area and remove 800, leaving a population of about 600, she said.
While population numbers can't be directly related to the birth control efforts because outside factors -- weather and predators, to name a few, can influence reproduction rates -- it is a good sign, Fluer said.
"It makes me think that there is some hope for this," he said, "and it could be working."
Wild horse populations, left to their own devices, double every four years.
"The range can only sustain so many animals," Fluer said. "So then what do you do? Do you let them starve?"
For years the BLM's biggest population control method has been wild horse adoptions. Ten years ago, 10,000 horses a year were adopted, Fluer said. Numbers have dropped in recent years to only 3,000 horses finding homes each year.
The BLM can't continue to gather horses and hold them long term, hoping they eventually will be adopted, he said.
The BLM has looked at other, more controversial, ways to control population. This year the agency proposed castrating captured stallions, but decided against it after public outcry.
"The horse in general is an important animal and part of our way of life in American history," Fluer said. "It's an emotional and sensitive issue."
Wild horse management has long been a contentious issue in North America. It's a political argument to even declare whether horses are native species, Fluer said.
Wild horses first came to North America in the 1400s with the Spanish.
Horses left on the range bred and created herds used by American Indians and, eventually, ranchers, who managed the animals like a crop, Fluer said. During World War I and World War II, people released horses on the range, unable to care for the animals while at war or supporting a family stateside.
Congress granted authority to the BLM in 1971 to manage wild horses. It is the only animal the BLM manages, Fluer said.
"People see it as a symbol of the American West," Beckwith said, "and they want to hang onto that."
Advocacy group responds
The American Wild Horse Preservation Campaign supports the use of PZP, which group members say is safe and effective.
"This is the optimal (management tool) as far as we're concerned," said Suzanne Roy, director of the group.
The problem the group has with the BLM is that the agency isn't using PZP enough. The birth control drug has been available for years and the BLM resisted using it, and is now underusing it, Roy said.
This year, the BLM originally said it would inoculate 2,000 mares, then dropped the number to 1,200.
"This is still barely making a dent in the populations," Roy said.
The organization should inoculate 4,000 mares, Roy said.
The BLM's roundups, which sometimes use helicopters, are inhumane, Roy said. And the gathers take more horses off the range than can be adopted, and those horses are left in stockyards. As the populations in stockyards pile up, the only option will be to slaughter the horses, she said.
Using PZP more often would not only save more horses, but also save money, Roy said.
The group has said for years it wants the BLM to change its focus from roundups and removals to managing the herds on the range, she said. Only those that can be adopted should be taken from the range, she said.
That is the eventual goal of the BLM, as well, Beckwith said.
And while Fluer said he hasn't yet compared data with other areas using the birth control, in the Red Desert it has put the BLM in "maintenance mode" for the first time and is the best "hope" for the managing the herds in the future.