National Elk Refuge to delay the start of supplemental feeding
by National Elk Refuge
January 17, 2010
National Elk Refuge Manager Steve Kallin announced that the supplemental feeding program for elk and bison wintering on the refuge will likely begin later this season than in most years. Above normal grass production and below average snow cover have delayed the need for supplemental feed, a management practice that typically begins during the third week of January.
"This is good news for the elk herd," Kallin said. "When supplemental feeding can be delayed, elk and bison are dispersed over a larger area for a longer period of time, reducing animal concentrations and the likelihood that disease will be spread throughout the herd." Reducing reliance on supplemental feeding is one of the primary strategies outlined in the interagency Bison and Elk Management Plan approved in April 2007.
Supplemental feeding of alfalfa pellets enables the National Elk Refuge to maintain a larger number of animals than the winter range would otherwise sustain. Biologists from the National Elk Refuge and Wyoming Game & Fish Department continually monitor environmental conditions and elk distribution to assess the need for supplemental feed. They focus on the availability of natural forage, estimating the amount of pounds per acre of grasses and forbs. If enough natural food is available, then snow conditions are evaluated to ensure the forage can be accessed by the wintering herds. Heavy snow or layers of ice can make it difficult for elk to paw through the dense layers to reach the food source. Regular condition assessments are important because a sudden change in weather patterns or snow depths can have a significant effect on the decision of when feeding is necessary.
Data collected earlier this week indicates that approximately 1,225 pounds per acre of accessible forage still stands at sample sites on the south end of the refuge, a 206% increase from the same date last year when 400 pounds per acre remained. Much of the increase can be attributed to an abundance of moisture early in the growing season, including 3.8 inches of precipitation in June, or more than double the historic average for that month. Additionally, average numbers of elk counted on the south end of the refuge during the fall period werethe lowest in 25 years. A late migration combined with disturbance from a south unit elk hunt kept animals from spending an extended amount of time on the south end of the refuge and consuming much of the forage that helps sustain the wintering elk population.
Currently, approximately 4,000 elk are on the National Elk Refuge, compared to 6,000 elk at this time last year. Bison numbers have remained low, too, with only 110 counted on the refuge this week, an 82% decrease from the same date in 2009. "We look at a number of factors to determine when to start with supplemental feed," Kallin explained.
"All indicators show the feeding program doesnít need to begin yet. Forage production was high, use of the refuge by both and elk and bison has been down, and snow depth is still minimal." Last year, supplemental feeding began on January 27, approximately one week later than the 10-year average start date. If current conditions prevail with little additional snow, supplemental feeding could be delayed for several weeks.
Even though the feeding season may have a later-than normal start date, the National Elk Refuge has resumed a herd health assessment program that was implemented last winter, increasing the monitoring of elk and bison health in relation to their environment during the feeding season. The projectís goal is to look more critically at how diseases are influenced by environmental conditions as well as management actions. "We need to look specifically at trends, so data collected prior to the feed season is valuable," Kallin said. "Good, sound research and monitoring are key for us to assess and modify management activities to reach our goals of wildlife health and disease reduction." The herd health monitoring program is being led by Dr. Thomas Roffe, Wildlife Veterinarian with the U.S. Fish and Wildlife Service.
A crew from the U.S. Fish and Wildlife Service Wildlife Health Office will complete routine lameness assessments to document the incidence of infectious pododermatitis, a condition known as "foot rot" which can allow bacteria to enter an animalís body and set up infection through cuts or abrasions to the feet, a common result of coming in contact with hard snowpack or icy conditions. Areas with large numbers of animals and heavy fecal contamination are likely to have a higher incidence of the Fusobacterium necrophorum bacteria. Staff from the National Elk Refuge and Wyoming Game & Fish Department will assist the crew with collection of elk and bison carcasses for complete postmortem exams. The exams, or necropsies, can determine an animalís cause of death and significance of other disease problems. In addition, animals exhibiting significant visible signs of disease may be removed from the herd for testing.