With a fairly light winter now transitioning to spring in western Wyoming, the Wyoming Game and Fish Department (WGFD) has ceased elk feeding operations on all state feedgrounds. This past winter, elk were fed the fewest number of days on record and the 3,500 tons of hay fed was the third lowest total since record-keeping began in 1975.
WGFD did not provide supplemental feed to elk at the Green River Lakes and Soda Lake feedgrounds in the Pinedale area as snow conditions and elk distribution did not warrant feeding. In addition, only a handful of elk were fed for just a 27 - day feeding season at the Fall Creek feedground south of Pinedale. Many of those elk spent the winter on nearby Halfmoon Mountain, which has received habitat treatments in the past.
Much of this reduced feeding was made possible by the relatively mild winter, but it is also the result of a new program being implemented by the WGFD, called the Target Feedground Program. The agency is well aware of the disease implications that come along with congregating elk at feedgrounds and continually tries to find ways to limit or modify elk feeding strategies to reduce the transmission of diseases, such as brucellosis.
The Target Feedground Project is a relatively new program, which emphasizes altering elk feeding practices. As such, WGFD has identified, or targeted, certain elk feedgrounds where they have the ability to feed less, shortening the feeding period by ending earlier or, as was the case this year, not feeding at all. Another part of the program calls for low-density feeding whereby managers spread out the feeding over a larger area.
To test whether spreading the animals out could reduce brucellosis transmission among elk, the department's Brucellosis Feedground Habitat (BFH) biologists used a combination of video cameras and elk fitted with proximity collars to see how many elk would come in contact with an elk fetus (not infected with brucellosis) that was placed on feedlines. Brucellosis is primarily spread by elk sniffing and/or licking an aborted fetus infected with the bacteria.
BFH biologists observed the pseudo-aborted elk fetus under different feeding strategies and densities of elk, and found that contact rates with a fetus were far less when elk were spread out on multiple adjoining feedlines as opposed to a long single feedline, which has been the traditional way of feeding elk.
The first study involved only traditional feedlines (published in the Journal of Wildlife Diseases in 2009), and found that about 75 percent of all elk-fetus contacts ('transmission events') occurred when the fetus was placed on the actual feedline. During the recent study of low density feeding, however, the cameras and collars recorded between 66 percent and 75 percent fewer elk-fetus contacts than during traditional feeding. According to Big Piney BFH biologist, Eric Maichak. "Based on these data, we're fairly confident that employing low density feeding will not only reduce the chances a fetus is aborted on a feedline, but also reduce the contact rates if a fetus were to be aborted because elk are simply spending less time densely aggregated on feedlines."
Another new feeding practice that has been implemented at the Bench Corral feedground is the use of two-ton bales distributed with a large tractor and bale feeder. Most other state feedgrounds still utilize horse-drawn sleighs to avoid potential mechanical failures. "We've found the bale feeder to be a good tool for low-density feeding because you can easily adjust the amount of hay that comes out and the ground up hay is more easily consumed by the elk, meaning the animals spend less time on the feedline," said Maichak.
A recent data analysis by the department's BFH biologists in collaboration with U.S. Geological Survey researchers suggests that shortening the feeding season will significantly reduce brucellosis seroprevalence. That study was published in the Journal of Ecological Applications in 2007. "We reviewed feeding duration and serologic data and found a strong correlation between a shorter feeding season and lower brucellosis exposure rates in elk," said Maichak. "Intuitively, the less time the animals spend concentrated during the disease transmission period, the lower the likelihood of encountering an infected fetus, and therefore the lower the prevalence of the disease." Like low-density feeding, a shortened feeding season is being implemented where possible.
To facilitate this practice, most target feedgrounds have been stocked with some grass hay, in addition to the usual alfalfa hay. By using less desirable grass hay instead of the high protein alfalfa at the end of the season, managers can coax elk onto native winter range earlier. Department personnel work closely with elk feeders to monitor elk behavior and winter conditions to decide when rations should be reduced to encourage elk to free-range.
It's always a balancing act," says Pinedale Region wildlife supervisor, Bernie Holz. "You'd like to feed the animals the least amount possible for disease purposes and to minimize department costs, but if the elk can't find natural forage they will go looking elsewhere and might end up in a cattle feedline or some other hazardous situation where you don't want them." This is why WGFD personnel have worked carefully to target feedgrounds that have low risk for elk/cattle commingling and have suitable winter ranges nearby, including some that have received habitat improvements to increase natural forage.