CODY, Wyo. — Elk moving farther into Wyoming counties surrounding Yellowstone National Park are frequently mixing with cattle and increasing the risk of passing brucellosis, wildlife officials say.
The expanded movement of elk surrounding Yellowstone has prompted state livestock officials to consider expanding the surveillance areas where cattle are vaccinated and frequently tested for brucellosis.
"Obviously, wildlife doesn't look at our designated surveillance boundary and stop," Wyoming State Veterinarian Jim Logan said. "We're seeing elk in Park and Lincoln counties, and to some extent in Fremont County, going outside the designated areas."
To address the issue, Logan said he'll recommend to the Wyoming Livestock Board that it expands the designated surveillance areas to include all of Park and Lincoln counties.
Any changes to the current boundaries would be subject to a 45-day public comment period. The Livestock Board would also have to change its Chapter 2 brucellosis rules to accommodate the expanded boundaries, Logan said.
The commingling of wild elk and livestock has become a thorny issue in recent years as more cattle test positive for brucellosis, a disease that occurs naturally in the wild and causes cows to abort their fetuses.
While some see the mixing of elk and cattle as a wildlife management issue, Regional Wildlife Biologist Brian Nesvik said the problem is more complicated than simply hazing elk away from feed lines.
"Right now is a difficult time when you talk about elk management and you try to come up with solutions," Nesvik said. "This brucellosis issue doesn't make things any easier at all."
Nesvik said the interest in elk reaches beyond the livestock industry. The animals help support the region's tourism industry, along with area outfitters.
Predation issues also make managing elk populations difficult, Nesvik said, while conservationists argue that elk, along with other wildlife, are entitled to historic feeding grounds now used by cattle.
"On the other side of the spectrum, we've got some areas of Park County where we can't kill enough elk and we have a hard time meeting our population objectives," Nesvik said.
Wyoming Game and Fish is working to prevent the commingling of elk and cattle. Sometimes the effort works, Nesvik said, and sometimes it doesn't.
"The key time of year we'd like elk and cattle separated is the time of the year when they're together more," he said. "When the snow line goes up and the grass starts turning green, the cattle follow the green line and the elk do the same thing."
Testing harvested elk
Nesvik said Game and Fish is working to increase hunter access on private land and to increase hunting tags in targeted areas.
Most recently, the agency extended the elk hunting season into January, hoping to increase harvest numbers.
Game and Fish used the opportunity to collect blood and tissue samples from hunter-killed elk. During the harvest, field observers collected the samples to test for brucellosis.
"We could tell producers what we thought the brucellosis levels were in elk and if they were increasing or declining," Nesvik said. "We got enough samples where we thought we could give a statistically valid estimate of what the serological prevalence was in elk across Park County."
Serology refers to the testing of blood for antibodies from a given disease.
Preliminary figures showed that among the elk monitored, the serological presence of brucellosis was 15.8 percent, up slightly from last year's 15.1 percent. In targeted areas, the level was 23.8 percent.
Nesvik said they collected more than 530 blood samples in the area, 340 of which were useful. Of those samples, roughly 200 were taken from targeted locations within Park County and the greater Yellowstone area.
"We want to continue to provide serological data over time to livestock producers so they have an idea what the trends are and what's happening as far as brucellosis goes in wildlife," Nesvik said.
While Game and Fish works to manage elk populations, Logan is working to help the livestock industry stay ahead of the brucellosis threat.
The current designated surveillance areas include Park County west of Highway 120 and Fremont County west of the Wind River Indian Reservation.
The area also includes Lincoln County north of the national forest border and all of Teton and Sublette counties.
Producers ranching within the proposed expanded boundaries who aren't threatened by brucellosis could be exempted from surveillance-area rules by developing a herd plan and by mitigating certain risk factors, Logan said.
"We have nearly achieved eradication of brucellosis in livestock in this country," Logan said.
"But with that, and with our continued programs in the greater Yellowstone area, other states continue to be very concerned about brucellosis in this area and what our three states (Montana, Wyoming and Idaho) are doing to make sure the disease stays contained within our designated surveillance areas."
Contact Martin Kidston at email@example.com or 307-527-7250.