More than three dozen wild horse advocacy groups have voiced their desire for federal authorities to make greater use of the fertility control vaccine PZP to manage America’s wild horses.
The groups contend that the PZP vaccine is a cost-effective alternative to roundups and removals of wild horses from the range – a federal strategy which has been widely condemned as expensive and ineffective.
Today’s call for greater PZP use represents a major stand among groups advocating for better management of the mustangs that inhabit the vast western rangelands. They see it as a way to stave off the fiscal problems sparked by wild horse roundups, with an increasing share of the budget going toward the long-term care of the captive animals.
Neil Kornzse, the director of the Bureau of Land Management (BLM), the agency charged with managing America’s wild horses, admitted recently that the current system of roundups was failing. He said the agency’s policy of mustering and keeping the horses in facilities could potentially cost $US1 billion over the life-span of the horses.
Already, 70 percent of the BLM’s $US80 million Wild Horse and Burro Program budget was spent on roundups and removals, while less than 1 percent of that amount was spent on long available, humane and effective fertility control.
Groups supportive of the use of the PZP vaccine for humane wild horse management include the:
The BLM has removed more than 40,000 wild horses from public lands in the last seven years alone.
The National Academy of Sciences (NAS) recommended the use of PZP in its 2013 study, Using Science to Improve the BLM Wild Horse and Burro Program, saying it was “a more affordable option than continuing to remove horses to long-term holding facilities”.
The NAS study also noted that roundups and removals of wild horses were actually responsible for “facilitating high rates of population growth on the range”.
The NAS added that “removals are likely to keep the population at a size that maximizes population growth rates, which in turn maximizes the number of animals that must be removed through holding facilities”.
PZP is an immunocontraceptive vaccine. It works with a mare’s immune system to produce antibodies that block sperm receptor sites on the zona pellucida, a thin membrane surrounding the ovum.
Because it is non-hormonal, PZP does not:
PZP has been used for more than 25 years in the wild horses on the Assateague Island National Seashore in Maryland. In that time, the herd has been brought to more sustainable numbers and the overall health of horses as a result has improved substantially.
In 1990, few horses on Assateague lived past 15 years. Now, many are living 30 years or more.
And, because PZP is not permanent, the National Park Service managers can closely control the herd’s population, allowing for increased births as appropriate.
Management programs with PZP have also helped curtail and even end roundups in wild horse management areas in the West, such as the Pryor Mountains on the Montana/Wyoming border, McCullough Peaks in Wyoming and Spring Creek Basin and Little Book Cliffs in Colorado.
In Colorado’s Spring Creek Basin, no mustangs have been removed since 2011, thanks to a BLM-facilitated public-private partnership using the PZP vaccine.
In addition, the BLM has committed to bait trapping if, in the future, the removal of some mustangs was necessary to maintain range health. Bait trapping is a far less traumatic capture method than helicopter roundups.
A PZP project on the McCullough Peaks range in Wyoming, meanwhile, helped the wild horse population there achieve zero population growth within three years.
Increased use of PZP and a reduction in roundups and removals would also be a boon to US taxpayers, helping to curtail the cost of the existing program.
The public now spends about $US49,000 for each mustang that is removed from the range and not adopted. PZP, meanwhile, costs about $US27 per darted horse per year.
One economic model published in the Journal of Zoo and Wildlife Medicine showed that the BLM could save $US8 million over 12 years by using PZP in one herd management area alone. Multiply that by 179 HMAs and the cost-savings reach the hundreds of millions, according to the advocacy groups.
Is Wyoming waking up to the reality of our nation’s unworkable approach to managing wild horses? The horse issue is so heated and divisive, that I’m a natural skeptic.
However, the recent news that a group of Wyoming legislators is urging the U.S. Bureau of Land Management (BLM) to rethink its approach to horses makes me, at least, somewhat optimistic.
According to an Oct. 28 article in The Horse magazine, legislators also plan to work with Gov. Matt Mead’s office to educate Wyoming residents about horse management issues. Although this discussion is prompted more by land-use concerns than by wild horses, more dialogue is welcome.
Federally protected wild horses on public land have no intrinsic economic value, yet compete with the enormous economic interests of the livestock industry, mining, energy development, and recreational use.
According to financial data supplied by the BLM to the Wild Horse and Burro Advisory Board, the agency spent 67 percent of its total annual $77 million wild horse budget, in 2014, rounding up, removing and stockpiling horses from federal lands. It spent a mere 0.3 percent on population growth suppression for 450 mares. Three of five wild horses now live in government holding pens and pasturages, costing taxpayers an estimated $120,000 per day. Worse, each removal merely speeds up the reproductive success of horses remaining in the field.
Although BLM field censusing is not scientific, the agency claims there are 40,000 wild horses on federal lands that can sustain less than 30,000. With few natural predators, however, populations will grow. The federal government’s Wild Horse and Burro Adoption Program can place only a few thousand horses each year. There is no good outcome to the current situation until BLM starts to aggressively curb wild horse population increases.
One strategy that could help significantly is more widespread use of wildlife contraception, as advised by the National Academy of Sciences in 2013. The immunocontraceptive vaccine, native PZP, has a long track record of success in wild horses, dating back more than 25 years.
Today, native PZP vaccine is used in more than 20 Herd Management Areas (HMAs)—several in Wyoming. Model PZP programs at McCullough Peaks HMA, near Cody, and the Pryor Mountain Wild Horse Range, traversing the Wyoming/Montana border, have sharply reduced population growth. Little Book Cliffs Wild Horse Range, near Grand Junction, Colorado, has also demonstrated the value of fertility control.
This vaccine blocks fertilization in mares and other animals, such as bison, elephants and urban deer. It can be administered by a rifle-fired dart and doesn’t harm existing pregnancies or an animal’s health. Unlike earlier, hormone-based wildlife contraceptives, PZP breaks down in the mare’s body and will not pass into the surrounding environment, or to other horses. The vaccine is also reversible.
BLM has been studying contraceptive agents for years and is said to be holding out for a longer-lasting vaccine. Mares that receive native PZP need boosters every year for the first two-to-three years and then every-other or every third year. This presents challenges in large HMAs. However, horses can be gathered expressly for treatment in temporary corrals through bait or water trapping. That presents a minor challenge compared to the expense and man-hours required for humanely accommodating growing numbers of once-wild horses. Had more HMAs started using immunocontraception 15-plus years ago, as advised by the scientific community, horse populations would be far lower.
In some HMAs and wild horse ranges, volunteer groups have been trained to dart mares with native PZP and to track those requiring boosters. This is far less costly than paying more and more to round up, feed and care for these animals off the range. Caring for a horse over a 30-year life span costs taxpayers around $45,000, compared to well under $1,000 to gather, treat, and release a wild mare with native PZP.
How long should we wait for the perfect solution? I hope our legislators and the BLM conclude that further delay in not using the best available tool we have—native PZP—makes no horse sense.
Source: OpEd Casper Star Tribune by Patricia M. Fazio, PhD
Patricia M. Fazio, Ph.D., is an environmental editor, historian, and scientist, with a special interest in the federal wild horse issue—leading to her dissertation on the Pryor Mountain Wild Horse Range, completed in 1995.
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