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Saving Wild Horses

The Humane Society of the United States

FEATURE: All Animals, Fall 2008
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A pioneering birth control method could prevent mass killings of an American icon.

by Mike Satchell

On public rangelands in 10 Western states, no sight is more magnificent than a herd of wild horses thundering across the landscape—manes and tails flying—silhouetted against red rock mesas or distant snow-capped mountains. It's an evocative glimpse of America's natural heritage, a timeless tableau of powerful untamed animals whose tragic history is the focus of deep and renewed concern. Once again, America's mustangs are on the brink of a crisis in which thousands could die. The reason, says the federal government: too many horses.

Killing unwanted horses is not a new concept; it was considered a viable solution for the better part of the last century. But The HSUS and its scientific collaborators have produced a humane and moneysaving alternative to prevent history from repeating itself: vaccine-induced birth control.

Contraception embodies the protective intent of the Wild Free-Roaming Horses and Burros Act of 1971, when Congress designated mustangs as "living symbols of the historic and pioneer spirit of the West." Approved by unanimous vote in both chambers on a tidal wave of public outrage, the law was written to safeguard animals who had been exterminated like vermin, their numbers reduced from 2 million in 1900 to about 17,000 seven decades later.

During those years, mass roundups of appalling cruelty resulted in slaughter of the herds for horse meat and pet food to satisfy politically powerful ranchers who grazed their livestock on public lands and didn't want wild horses competing for water and forage. The new law stopped the killing and the herds rebounded, but Congress's 40-year-old promise of perpetual protection now rings hollow. The federal Bureau of Land Management, which administers 140 million acres of Western public lands in the continental U.S., announced this summer that it is considering euthanizing thousands of mustangs to reduce the population on the range, plus thousands more in permanent holding facilities.

Supply Exceeding Demand

While some 4 million cattle and sheep and 3 million big game animals occupy Western rangelands, the BLM—under continuous pressure from ranchers—permits only 27,000 mustangs to share the range in certain defined areas. That's less than half of 1 percent of the large grazing animals on public lands. The BLM rounds up about 8,000 to 10,000 "excess" horses annually and offers them for adoption for a $125 fee and a promise to keep them for one year. Supply, however, has always exceeded demand.

Some 10,000 mustangs are held in temporary corrals waiting for owners. Another 23,000 older, unadoptable animals are permanent wards of the government, living on private ranches under BLM contract. Adoption rates have dropped from more than 8,000 a year to less than 2,000, and today's skyrocketing hay and grain prices will only hasten that downward spiral.

If these trends aren't reversed, says Dean Bolstad, deputy division chief of the BLM's wild horse program, the current rangeland population of about 33,000 horses will double in four years to more than twice the permitted 27,000. To compound the problem, federal dollars are dwindling. This year the BLM is $7 million short of the $43 million it needs to support the programs. Unless Congress ponies up more millions, ranchers graze fewer cattle on public lands, or adoptions increase to record levels, the BLM will need to change course dramatically.

Most of the agency's options are far from ideal. It can allow the horses to run free and multiply on rangelands already overgrazed by cattle and stricken by drought, worsening the deterioration. It can round up and legally euthanize herds. It can hold unrestricted public sales that would send thousands to abattoirs in Mexico and Canada to be butchered for export to Europe and Japan, where horse meat is a delicacy. (The last horse slaughter plants in the U.S. were shut down in 2007.) Says Bolstad: "We are in a tremendously difficult situation with few alternatives."

The prospect of another wild horse holocaust adds urgency to the joint five-year contraception program now in early testing by The HSUS and the BLM. For two decades, The HSUS has worked with wildlife fertility specialist Jay Kirkpatrick, director of the Science and Conservation Center in Billings, Mont., to produce a safe, effective method of birth control for wildlife.

Proven Successes

The most common vaccine used today on large animals is PZP, a protein that stimulates the immune system to block fertilization and prevent conception. A landmark study involving 600 mustangs, financed by a $1.7 million grant from the Annenberg Foundation and using vehicles provided by Land Rover, is intended to demonstrate that vaccine-based birth control—known as immunocontraception—is a humane and effective way to maintain Western herds.

Once the method has been validated, the program will be expanded to between 8,000 and 10,000 mares. On its success depends the fate of countless animals whose ancestors helped carry the Lewis and Clark expedition on its epic journey and played an integral role in the opening and settling of the Western frontier.

For docile equine herds and other animals, the PZP is delivered from close range with a rifle dart fired from the ground or a helicopter, making it relatively easy to hit a semi-tame doe in an urban neighborhood, a tourist-habituated wild mare on an Atlantic Coast barrier island, or a large elephant cow in the bush. Fleet and skittish mustangs, however, pose a tougher challenge; they must be darted at close range.

The focus is now on two test herds in Utah and Colorado, where the first mares were injected with PZP this fall in the joint HSUS/BLM study. Hopes for a positive outcome are high following the success of a project launched by The HSUS in 1994 to control a herd of 175 wild ponies on Maryland's Assateague Island National Seashore.

Zero population growth was achieved in two years, and the herd was reduced to 135 animals by the 11th year. The effect on mares given PZP was dramatic: Freedom from the rigors of repeated pregnancy, birth, and lactation increased their average life span from 6 years to 20 years. Some of the ponies have now surpassed the ripe old age of 30.

Birth control has the potential to save the tens of millions of taxpayer dollars spent annually to round up, adopt out, or warehouse thousands of horses the ranchers detest and the government deems expendable. Instead of resorting once again to cruel and clumsy mass killings as a temporary solution to "overpopulation," the U.S. Congress should keep its promise and adequately fund the BLM wild horse program until immunocontraception can be implemented on the Western rangelands.

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