Latest suit to block Nevada mustang roundups targets drugs

A federal judge has agreed to let wild-horse advocates make their case for a court order blocking another mustang roundup in Nevada in a legal battle underscoring divisions among protection groups over the use of a fertility drug to slow herd growth.

U.S. District Judge Larry Hicks set a Feb. 9 hearing for the request for a temporary injunction prohibiting the government from gathering 332 horses in the Pine Nut Range southeast of Carson City.

The U.S. Bureau of Land Management agreed to postpone at least until later this month the roundup that had been scheduled to begin last week.

Friends of Animals and Protect Mustangs filed a lawsuit late last month accusing the federal agency of violating the National Environmental Policy Act with the plans to ship about 200 animals to holding pens and return the others to the range, including an estimated 66 mares that will be injected with the fertility control drug, PZP (porcine zona pellucida).

A new filing last week seeking a restraining order says the agency plans are based on an outdated 2010 environmental assessment that doesn’t adequately address the physical, behavioral and social impacts of PZP on wild mares.

Critics say the only public comment federal agency obtained was on the old assessment from Aug. 23 to Sept. 23, 2010. “A mere 30-day public comment period” failed to provide the public reasonable notice “that more than four years later the Pine Nut herd would be made subject to a hasty roundup in 2015,” they said.

The lawsuit says the federal agency also ignored other studies back then suggesting PZP “likely creates instability in wild horse bands, affects the health of horse and can increase wild horse mortality.” “Since the 2010 EA, significant new scientific information has become available further demonstrating the negative impacts of PZP,” the lawsuit says.

The research includes a paper published later in 2010 in the scientific journal PLOS ONE by Cassandra Nunez, an adjunct assistant professor of ecology at Iowa State University. She was a researcher in Princeton University’s Department of Ecology and Evolutionary Biology when she wrote the paper concluding the Bureau of Land Management’s earlier assessment was “accurate regarding the information that was available at the time.”

“It is outdated now,” she said in a 40-page affidavit attached to the lawsuit Thursday. “Recent research has demonstrated changes in mare stress and reproductive physiology, in addition to changes in male behavior.”

Bands of wild horses historically are stable, with mares staying with the same males much if not all of their lives, the lawsuit says. “However, when they have been treated with PZP and mares cannot get pregnant, they will leave bands.”

Bureau of Land Management officials said they cannot comment on pending litigation. But the agency said on its website that it uses PZP in cooperation with the Humane Society of the United States under FDA rules that apply to research on new animal drugs. “The PZP vaccine does not affect unborn foals, and the vaccinated mares return to normal fertility within four years,” the Bureau of Land Management said.

The National Cattlemen’s Association and others back PZP to supplement roundups of horses they say are robbing their livestock of precious forage. The National Academy of Sciences advanced the idea in a 451-page report in 2013, recommending fewer roundups and more emphasis on fertility control.

While horse groups unanimously oppose roundups, some disagree about PZP.

The American Wild Horse Preservation Campaign, the largest coalition of horse groups in the nation, was among those who urged increased use of PZP in 2011.

“The PZP vaccine represents the most humane and cost-beneficial alternative to the current, cost-prohibitive wild horse removals,” said the policy statement signed by members of the Humane Society, American Society for the Prevention of Cruelty of Animals and Animal Welfare Institute.

Anne Novak, executive director of the San Francisco-based Protect Mustangs, argued that the artificial manipulation of the herds “takes away their freedom to live as nature intended.”

“Management based on PZP drugging is setting up wild horses and burros to be controlled in large zoo-like exhibits on public lands,” she said. “They need to be left alone.”

The Bureau of Land Management said a population survey in August determined there were 332 horses in the horse management area — more than twice as many as it says can be sustained over the 140 square miles in Lyon and Douglas counties.

Craig Downer, a wildlife biologist who works with Protect Mustangs, denied that the Pine Nut herds are overpopulated. He has observed the horses for years and documented that PZP will “disrupt normal social interactions and cause much frustration and dysfunction.”

Problems with PZP have been covered up by proponents, including “wild horse supporters who are being manipulated into supporting PZP,” Downer said.