Elk evade traps
by Cat Urbigkit, Pinedale Online!
January 27, 2009
Dozens of Wyoming Game and Fish Department personnel spent Sunday and Monday on standby in the Pinedale regional office, awaiting word that elk had been trapped and were ready to be processed for brucellosis testing. But the elk refused to cooperate.
Hay was placed in traps at three Boulder-area elk feedgrounds in attempt to bait the elk inside, but the elk declined to enter. After two days of failure, WG&F came up with a new strategy, planning to stay on site overnight Monday in attempt to capture any elk that enter the traps under the cover of darkness.
The effort kicks off year four of the five-year elk test and removal pilot project. Personnel from the Wyoming Game and Fish Department and other agencies also plan to conduct further elk capture operations during the week of February 8, 2009.
The pilot project was one of 28 recommendations made by the Governor's Brucellosis Coordination Team in a comprehensive effort to deal with brucellosis in Wyoming. The members of this group were tasked to come up with effective long-term solutions to the brucellosis problem in Wyoming and new ideas on how to manage brucellosis.
Beginning this year, trapping efforts will be conducted at all three elk feedgrounds within the Pinedale elk herd--Muddy Creek, Scab Creek and Fall Creek feedgrounds--along the west slope of the Wind River range south of Pinedale. Trapping was done only at Muddy Creek feedground the first two years and expanded to include Fall Creek feedground last year.
In all, agency personnel have captured and handled just over 1,200 elk in the first three years of the pilot project. From those, nearly 600 were test-eligible adult cows that were bled to test for exposure to brucellosis. Of the female elk bled, 113 tested seropositive for the disease and were removed from the population. Additionally, there have been a total of 13 trapping-related mortalities over the three years of trapping. When handling such a large number of elk, capture mortality is always a possibility.
Members of the Governorís Brucellosis Coordination team determined that capturing a large proportion of the total female elk within a feedground population is imperative to achieve the objective of the test & removal pilot project, which is to get a statistically significant reduction in brucellosis seroprevalence. With the extensive trapping efforts at the Muddy Creek feedground to date, workers have been able to capture 60%, 35%, and 62% of the test-eligible female elk in 2006, 2007 and 2008, respectively. Brucellosis seroprevalence rates decreased from 37% to 16% to 14% over those same years.
Interestingly, of the elk that have been recaptured, approximately 10% of female elk that originally tested negative later tested positive. This happened in both 2007 and 2008. This would indicate that an exposure event, such as a fetus being aborted on the feedground, likely occurred in the winter/spring of both 2006 and 2007.
Approximately $815,000 has been spent on the test-and-removal pilot project to date. The trapping operation has typically involved between 50 and 60 personnel from Game and Fish and other agencies. All blood testing is performed by Game and Fish personnel working at the Wyoming State Veterinary Laboratory in Laramie.
The project has been a large cooperative effort between the Wyoming Game & Fish Department, USDA Animal Plant and Health Inspection Service (APHIS) Veterinary Services, the University of Wyoming, Wyoming State Veterinary Laboratory, and Sublette County Sheriffís Office and Sublette County Road and Bridge.
"A number of logistical challenges have been overcome to conduct these elk trapping efforts, not the least of which is snow removal on the roads into the feedgrounds," said Talbott. "Blowing and drifting snow has been an issue each year and we canít thank the Sublette County Road and Bridge folks enough for their efforts."
In addition to the removal of seropositive elk, there is also valuable research in brucellosis management evolving from this scientific experiment. Currently, blood samples from captured elk will only show if the animal has been exposed to Brucella abortus, the bacteria responsible for brucellosis infection. Tissue samples will be collected from all seropositive elk. These tissues will be cultured to determine if the slaughtered animals were actually infected and capable of transmitting the disease.
There is other important scientific research that is making use of the biological samples. Biologists are utilizing fetuses removed from elk that are culture negative, or unable to transmit the disease, in a project examining scavenging rates on feedgrounds. This research recently led to implementation of the Target Feedground Project, an effort to reduce brucellosis prevalence in elk by utilizing low-density feeding methods combined with shortening the length of the feeding season.
There is also cooperative research being conducted with the United States Geological Survey on the relationship between parasites, such as lungworms, and rates of brucellosis infections on feedgrounds. Some evidence suggests that parasites may play a role in disease transmission.
Elk feedgrounds have been active in northwest Wyoming for nearly a century. The first feedground established in Wyoming was at the National Elk Refuge in 1912. Today, there are 22 state-operated feedgrounds in Wyoming, in addition to the National Elk Refuge, which is operated by the US Fish and Wildlife Service. In an average year, around 13,000 elk are fed on state feedgrounds. Around 6,000 are fed on the National Elk Refuge each year.
Brucellosis transmitted to cattle herds from elk caused Wyoming to lose its brucellosis free status in 2004. Wyoming regained its Brucellosis Class Free status in September 2006, however cattle from a herd near Daniel were found to be positive for the disease in June of 2008. If a second Wyoming herd were to test positive, the state could again lose its brucellosis free status, thus limiting its ability to freely market its cattle. Ongoing research, along with other management practices, is an important part to eliminating brucellosis in wildlife and maintaining Class Free status for Wyoming.
The Governorís Brucellosis Coordination Team made the recommendation for the pilot test-and-removal experiment to last five years. Elk will be captured and tested at all three elk feedgrounds in the Pinedale elk herd this winter and the winter of 2009-2010, thus completing the five-year pilot project. A comprehensive review of the pilot project will be completed by the Governorís Brucellosis Coordination Team at that time.