News

Let Them Be!
Not PZP

The Annenberg Foundation, according to its mission statement, “exists to advance the public well-being through improved communication.” The statement continues: “As the principal means of achieving this goal, the Foundation encourages the development of more effective ways to share ideas and knowledge.” In June 2007, the Humane Society of the United States received a grant of $1.76 million from the foundation for a project called “ Assateague of the West: Protecting Wild Horses Through Immunocontraception.”^[1] But how does this relate to sharing ideas and knowledge? And, most important, what, or who, is this really protecting?

The grant involves the use of Porcine Zona Pellucida (PZP), a contraceptive vaccine HSUS has been pushing for years, that prevents pregnancy in an animal by blocking fertilization of an egg. But nobody asked the horses if controlling their reproductive lives would help protect them.

Human influence over the centuries -- mainly involving the killing of wolves, cougars and other large carnivores in order to protect cattle businesses -- helped the horse and burro populations to grow unchecked in the first place. To this day, cattle ranchers using subsidized public lands promote the killing of carnivores such as wolves and coyotes, and monopolize valuable natural resources needed for free-roaming animals’ survival.

Some of these resources were set aside for horses and burros in the Wild Horse and Burro Act of 1971. But catering to the interests of agribusiness has taken precedence. So the Bureau of Land Management, under pressure from those with interests in the land and from wild horse advocates, has, in some places and at certain times, seized upon a method to please both parties: contraception. It’s touted as a humane manner of population control, a win-win solution. But horses and burros stand to gain nothing and potentially lose plenty through forced contraception.

Studies on PZP use (which include testing on a wide variety of animals, often in captivity and sometimes involving death, to dissect the bodies) suggest that we do not know the unintended consequences this intrusive practice can have over time -- consequences involving animals’ social structure, stress levels, physical health, sexual interactions and possible disease transmission. Some studies indicate little adverse effects; others say the opposite. A recent paper by Cassandra Nunez, “Effects of Immunocontrception With Porcine Zona Pellucida (PZP) on the Behavior of Wild Horses,"^[2] states “that contraception with PZP significantly alters the social behavior of Shackleford Banks horses, refuting prior studies of other wild horse populations. This work demonstrates the risks of making managerial decisions in one population based upon limited data collected from another.”

One thing we do know with certainty: Without the natural kind of stress reproduction places on free-living animals, mares live significantly longer than they would on nature’s terms -- and this effect thwarts the intended population result of the contraceptives. Thus, arguments over whether this substance is effective,along with more intrusive research projects, are likely to continue for years.

Since HSUS began introducing the contraceptive known as PZP to wild horse populations in 1988, they have pooled resources to develop the vaccine with federal park administrators and the Bureau of Land Management within the Interior Department. Under the law, the BLM is to “preserve and maintain a thriving natural ecological balance.” Yet an aerial survey of north-central Nevada conducted in June 2010 found that cattle outnumber wild horses ten to one.^[3] And this is an area where the free-living horse and burro population is intrusively managed. Quite arguably, then, the work of HSUS is in solidarity with ranchers’ financial interests, and not the horses’ best interests.

Meanwhile, potentially unnecessary roundups continue on the taxpayers’ dollar. Public lands continue to be subsidized and sold to cattle ranchers and development interests. And the unknown long-term effects of PZP will reveal themselves in field studies funded by people and groups who aren’t told there’s a better alternative: Let the horses and burros be.

The Humane Society’s fertility control collaboration with the BLM and others completely avoids the animal advocate’s most important issue: human dominion, and what we need to be doing right now to challenge that. Horse and burro population levels, to the extent that they do grow, are a direct result of humankind’s past and present dominion over their natural predators. To think that wild horse populations can be better managed by humans than nature is foolish.

The staff, members and supporters of Friends of Animals have consistently advocated for free-living animals to live on their own terms, and nowhere is that call more important than on the exploited and battered lands of the West.

Footnotes