State vet: Combat CWD by reducing elk feeding

Wyoming Game and Fish Department can best combat deadly chronic wasting disease by reducing artificial feeding of elk in winter, the agency’s wildlife veterinarian said last week.

“If we want to really look at proactive management, the single most proactive thing we can do for feedgrounds in the face of CWD is to find ways to reduce reliance on feed before CWD ever hits,” Dr. Mary Wood told Game and Fish commissioners at their meeting last week in Rawlins. But Wood would not recommend strategies to accomplish that because of feedground politics; “I know these are pretty complicated political issues,” she said.

Instead, Wood proposed management-based research like hunting seasons focusing on the leading edge of the disease to temper CWD’s advance.

Game and Fish commissioners had asked for a briefing on CWD, seeking a proactive approach to combatting the fatal neurological disorder that has no cure. Although the state agency is already updating its CWD management plan, commissioners sought a better-defined attack against the ailment.

RELATED: Study: Chronic Wasting Disease kills 19% of deer herd annually

Feedgrounds replace some winter habitat lost to development. They shortstop elk from historic migrations and help keep wildlife off highways and private pastures where they might cause damage or spread disease to livestock.

Feedgrounds help maintain a statewide elk population of more than 113,000 animals that allows almost 25,000 to be killed by hunters annually. They also create a micro economy for the cultivation, supply and distribution of artificial feed and for the outfitting and guiding of hunters. Feedgrounds enhance wildlife viewing, and wintering grounds are tourist attractions.

But they also facilitate the spread of disease among concentrated elk.

“We know that will occur,” Wood told commissioners. “I would be doing my profession and the oath that I took as a vet a disservice if I didn’t say artificially concentrating animals over a feed source will facilitate disease transmission.”

Wyoming no longer “control” in CWD experiment

Commissioners invited Wood to give a comprehensive CWD presentation, which she delivered last week. Board members were upset to learn that Wyoming has been acting for decades as a “control” state where the results of no action against the disease could be compared against states where culling and other methods were being tried.

“We’ve done nothing in the wild,” Shane Moore, a Jackson-based filmmaker, told the commission in Rawlins. “We now have the highest rates of CWD in the world.”

RELATED: Chronic Wasting Disease vaccine fails elk test

Commissioners no longer want Wyoming to be the control group. “We’re the losing half of that experiment,” commissioner Charles Price said.

“There’s not going to be any more of this control business,” board member Richard Klouda said. Commissioner Mark Anselmi agreed, saying “you’ve got a commission that’s desperate to be proactive in the CWD field.”

“Let’s send that message to the world,” commissioner Pat Crank said. “As far as the commission – we want to be proactive and combat chronic wasting disease.”

CWD has the potential to reduce wildlife numbers, Wood said, referring to five studies. A survey of hunters also showed that CWD infection curbs enthusiasm among that group.

Hunters queried in 2004 showed significant reluctance to pursue elk if they knew half a herd was infected. “Thirty-eight percent of Wyoming elk hunters said that they would stop hunting,” Wood said.

“This is what happens in the absence of CWD management,” she said. “It’s probably time for us to start considering active CWD management.”

Although the commission didn’t vote on the issue, it asked Wood to work with the agency’s wildlife division and return with a plan for action.

“I would like to move from monitoring to actively doing something,” commission president T. Carrie Little said. The board will allow the department to continue to update its CWD plan — comments are due on draft revisions April 1 — and perhaps add more active elements to it later.

Because Game and Fish does not have a research arm, Wood recommended “applied management” that would essentially conduct experiments in the field. “Multi-management strategies” could see hunters target “seed populations,” among other things. Fencing elk and deer out of private haystacks and even natural mineral licks could limit concentrations of wildlife. Modified hunting seasons in high-prevalence areas could produce more visible results than in areas of low infection, she said.

Could wolves eliminate CWD?

None of the commissioners talked about eliminating feedgrounds in approximately two hours of discussion last week. They asked Wood, among other things, whether coyotes, crows and other predators, which are immune to CWD, could spread the disease.

Wood said she was unsure of the impact of CWD prions — the malformed protein that’s the root of the malady — digested by predators and eliminated in feces. Commissioners asked whether Game and Fish could experiment with predators to find out.

Live infected moose, deer and elk replicate the malformed protein and spread it, but dead ones do not. Predators, “tend to prey on the old, the young, the weak and the sick,” Wood said. Even before deer display obvious signs of infection, mountain lions “seem to be able to pick out these animals,” because of behavioral changes.

Wolves may be better at killing infected animals. “There are some who actually think wolves may be far more effective at selective predation than mountain lions,” Wood said. Wolves are roaming hunters while lions use “stalk-and-pounce” strategies.

Some researchers, “actually predicted in their model that wolf predation could have the potential to significantly decrease CWD prevalence, perhaps even eliminate it,” Wood said. “I think it is important that we do take this into consideration when we are considering CWD management and when [we] are considering predator management as it relates to disease control.”

Coming soon to an elk feedground near you

The areas where CWD has been found in Wyoming increased by about 4 million acres in 2015 and early 2016 according to Wyoming Wildlife Advocates and Sierra Club, Wyoming Chapter. In the 15 years prior, the CWD endemic area expanded at an average of 1.8 million acres per year, the groups said. They recently released a map showing how CWD has spread across the state, based on information from Wyoming Game and Fish Department and other sources.

Federal officials have already adopted predators as a disease-controlling agent and incorporated them into their wildlife plans. The Bridger-Teton National Forest, for example, last year renewed a Game and Fish feedground permit that included an “implementation guideline” that Wyoming consider wolves disease-controlling scavengers on the seven or so Wyoming elk feedgrounds on national forest lands. Absent such guidelines, Wyoming’s plan for wolves allows for killing them when they significantly disrupt elk feedgrounds.

“The Forest Service expects that WGFD will consider gray wolves as a ‘scavenger’ when applying their ‘no harassment/harvest of scavengers on feedgrounds’ Best Management Practice…” the permit says. Bridger-Teton National Forest Supervisor Patricia O’Connor issued the permit for the Alkali Creek feedground in the Gros Ventre River drainage just east of the National Elk Refuge in Jackson Hole.

When O’Connor signed the permit she acknowledged growing worries about concentrating elk in high-elevation, snowbound pockets. “I make this decision knowing that there is a concentrated effort among local, state and federal agencies and the public they serve to restore historic migration routes, ensure the production and availability of natural winter range, protect private land from elk damage, and to address current and emerging wildlife disease issues,” she wrote. “In making this decision, I am recommending that the WGFC/WGFD transition away from the need for supplemental feed for elk. Use at Alkali Creek feedground is not intended to be permitted in perpetuity.”

At the National Elk Refuge adjacent to Jackson, the U.S. Fish and Wildlife Service that operates the reserve also worries about CWD. It has been trying for nine years to reach a goal of having no more than 5,000 of the Jackson elk herd’s 11,000 population on feed — and then only once every two years. The latest count found 7,300 elk feeding on the refuge.

Refuge manager Steve Kallin told people attending a forum earlier this year of his agency’s CWD fears. “Do we really want to concentrate [CWD] and amplify it on the refuge,” he asked. Concentrating a population infected with CWD could contaminate pastures for decades, he said, which is “the last thing we want.

“Instead of elk coming to survive the winter they would come to become infected,” he said during a recent tour of the refuge.

Wyoming Game and Fish sets the population objective for the herd, 80 percent of which is on the refuge this winter. While Kallin’s guiding 2007 Bison and Elk Management Plan calls for fewer elk, his agency does not and will not use starvation as a population-control tool.

“All the elk and bison that come here get fed,” he said. “We feed so the least dominate – the calves – get fed and are healthy.” Calf mortality on the refuge averages 3.4 percent, he said, whereas in a natural population that rate can go as high as 40 percent.

A wildlife veterinarian with the U.S. Fish and Wildlife Service recently visited the refuge and found rump fat on all nine elk she handled, Kallin said. (They had been tranquilized for fitting with tracking collars.) By comparison, unfed elk in Yellowstone National Park had no rump fat.

Feeding elk well does not insulate them from CWD state veterinarian Wood said. “All the nutrition in the world is not going to allow that immune system to recognize that [CWD prion] as abnormal,” she said last week in Rawlins.

The impact of milder diseases on concentrated elk could be a harbinger of CWD’s impact. Last winter crowding from 8,300 elk on the refuge led to an outbreak of hoof rot — bacterial infections from treading in feces-polluted mud. Hoof rot claimed close to 9 percent of calves, Kallin said.

“A lot of animals concentrated in an area is not a good idea,” Kallin said. However, it is increasingly difficult to keep elk spread out among remote, higher-altitude wintering grounds. Many elk have stopped wintering on state feedgrounds up the Gros Ventre River and on hillsides in northern Jackson Hole’s Buffalo Valley. Whereas Game and Fish wants 3,500 elk to winter on Gros Ventre River feedgrounds, last year only 1,100 stayed there. This year the count is about 1,600, Kallin said.

Recent reports of wolves killing 17 elk calves on a Game and Fish feedground in Bondurant could illustrate why elk disfavor such feeding outposts that have usurped their historic migrations and kept them in snowbound country. Photographs of the elk carcasses were widely circulated on social media and reported nationwide, including in the Jackson Hole News&Guide.

Wyoming’s brucellosis plan for the Hoback Herd that includes animals on the wolf-targeted McNeel Feedground in Bondurant calls for “no harassment/harvest of scavengers on feedground.”

With 80 percent of the Jackson elk herd concentrated on the National Elk Refuge, conditions are ripe “for a large die off,” Kallin said. “CWD is a real concern — it’s anticipated it will arrive.” Colorado researchers, among others, found the disease reduces wildlife populations, including in Rocky Mountain National Park, where the most concentrated elk occur at a density of less than one elk per two acres.

On the refuge concentrations are “150 times greater than that even when we are spreading them out,” Kallin said.

(This article was corrected to reflect the proper date of the Bison and Elk Management Plan — 2007 not 1997 — Ed.)