Contraception for wildlife? It might work in some cases

Utah • While one drug is being analyzed for effectiveness on a herd of horses, officials think it could be an option for curbing deer numbers in residential areas.
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At a time when state wildlife officials are doing everything they can to help Utah's mule deer herds grow, it may seem contrary to talk about controlling the animals with contraception.

Yes, birth control for wildlife.

It is an alternative idea to limit the number of animals in areas where hunting is not allowed — such as residential neighborhoods — or on species where hunting is not an option.

The Utah Legislature passed the "Administering Substances to Wildlife" bill in 2009, but that doesn't mean Division of Wildlife Resources (DWR) officials will be handing out pills, providing sponges or setting up condom machines any time soon.

"It wasn't because we want to start doing it in Utah now; it's because we wanted to control all things that are administered to wildlife," said Alan Clark, assistant director for the DWR. "And we wanted to be ready if we needed to do it at some point."

Federal officials in Utah, on the other hand, have been using birth control on wild horses for several years and plan to expand the program in order to maintain a healthy population of the animals on the available rangelands.

"Right now, it is one of the few tools we have [to control the population]," said Gus Warr, director of the Bureau of Land Management's Wild Horse and Burro program in Utah.

Wild horses in Utah are, of course, not hunted. The only means BLM officials currently have for reducing herds is rounding the horses up and putting them up for adoption. Tough economic times have drastically diminished the number of people interested in adopting wild horses. In fact, Warr said it does seem like some people, who probably can't afford to stable and feed their animals, are taking horses into the wild and releasing them.

A herd of wild horses in the Cedar Mountains Herd Management Area roughly 50 miles west of Salt Lake City is one of two in the country taking part in population control research of the liquid drug PZP (porcine zona pellucida). The research proposal was submitted by the Humane Society of the United States and was funded by the Annenberg Foundation. The Cedar Mountains herd research started in 2008. A herd in Colorado is also part of the research project.

BLM officials have been investigating possible contraceptive alternatives for wild horses since the late 1970s. Hormone implants, chemical vasectomies and intrauterine devices have been tried. Approval of the use of PZP as an investigational animal drug has been granted by the Food and Drug Administration.

Early indications, according to the BLM's website on wild horses, show the injection treatments reduced foaling by one-third to two-thirds in the two populations.

"This is not long-lasting. The drug can wear off, and that mare has an opportunity to give back in the future," he said. "Another thing about it is that it doesn't hurt an unborn foal if given while the mare is already carrying."

The Utah horses in the research project are taking PZP-22, a 22-month dose. If they are injected at the right time, late fall or winter, it can keep a mare from foaling for two years.

Warr said permanent sterilization is something that has not been mentioned much over the years, but with wild horse adoptions in decline and a lack of funding for the program, the topic has come up in discussion.

Clark says if there ever was a need to utilize contraception for deer it would be in places along the heavily urban Wasatch Front, where homes have been planted on historic winter range.

In Bountiful, with the approval of the City Council and mayor, wildlife officials have reduced deer numbers by shooting more than a dozen in heavily populated areas. It is a controversial program. Some residents call the deer "urban rats," but others enjoy having wildlife in the neighborhood. While it may be nice to have big game animals in your yard, they can get expensive when they break fences, eat gardens and total vehicles in accidents, which can also lead to human injuries and death.

Deer contraception seems like a good idea, but Clark says it would require about the same effort as elimination.

"It can't be broadcast for the animals to eat," he said. "It has to be given to an animal by injection. We have talked about it as a possible option, but it is also not something that will reduce populations. It may help stabilize a population, but you still have to get the numbers to the level you want them at first."

Transplanting the deer is another possibility, but efforts in previous years have shown little success. —

Wild horses in Utah

Bureau of Land Management officials oversee wild horse and burro populations in Utah. The majority of wild horses are located on the western edge of the state between Tooele and Iron counties. There are also smaller herds in the Book Cliffs and on the San Rafeal Swell. There are two small herds of wild burros in Utah: one in Wayne County near Hanksville and the near Green River along Interstate 70.

Biologists say the appropriate overall management level is about 2,000 animals. They estimate the current level between 2,600 and 2,700.

Mule deer in Utah

Utah Division of Wildlife Resources officials have set a long-term mule deer population goal of 426,000.

Sources: Bureau of Land Management and Utah Division of Wildlife Resources