Wild-horse roundup necessary, but not enough, officials say - DVM
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Wild-horse roundup necessary, but not enough, officials say
BLM looks to birth control, new studies as population spikes and adoptions decline


BLM started mapping out a new strategy for the wild-horse program back in October 2009 and now is in the second phase of that process, says Abbey, which includes analyzing public input on the program.

The BLM will issue a "proposed new direction" for its Wild Horse and Burro Program sometime in early 2011, taking into account more than 9,000 e-mails and letters on the development of a new, more sustainable strategy.

BLM also has been working with Saving America's Mustangs Foundation, headed by Madeleine Pickens, for more than two years. Pickens has proposed creating a wild-horse sanctuary where she will place horses gathered from Western public rangelands, but BLM says it can't move forward with the plan without a written proposal and proof of cost savings for taxpayers, among other things.

"BLM is doing its best to perform a very difficult job," OIG writes in its report, adding that current projections show wild horse and burro populations growing from 38,365 in 2010 to 238,000 by 2020 without further population control efforts.

Tom Gorey, a BLM spokesman, says that prior to this year, non-hormonal birth control was a rarely used method on wild horses, with only about 500 given doses each year.

Eleven wild-horse gathers are planned for 2011 for the primary purpose of applying fertility control methods. These "catch, treat and release" gathers will test a fertility control vaccine called porcine zona pellucida (PZP) on 1,000 mares. The vaccine, pioneered as a birth control method for wildlife in the 1980s, essentially creates an antibody to stop sperm from attaching to the ova.

"If these fertility-control treatments prove successful, we can lengthen the time between some gathers, saving taxpayers dollars by holding down gather and holding costs," Abbey says.

But PZP, a non-hormonal contraceptive, and gender-ratio adjustments have had little impact on populations to date, according to OIG's report.

"Neither of these measures currently provide an effective means to limiting the population of wild horses and burros at a level that can be sustained on public lands," the report states.

BLM began testing PZP on a small scale in 2004, but would need to use the drug on 70 to 90 percent of its mares to effectively reduce population growth, OIG says. BLM has plans to increase its PZP use in 2010, but not to those levels, according to Gorey.

"In addition, the vaccine becomes progressively less effective after the first year it is administered," OIG says. "Due to the large size of herds and vastness of the HMAs, the effectiveness of fertility control using PZP is currently limited."

PZP is not commercially available, and is being used by BLM in cooperation with the Humane Society of the United States and the U.S. Food and Drug Administration (FDA). The drug has been tested on a small herd of wild horses at a Maryland national park, and decreased pregnancy rates were recorded.

"We're not convinced it's a miracle drug, but we'd like to see how well it will work," Gorey says.


Source: DVM360 MAGAZINE,
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