EFFECTS OF WOODY BROWSE ON DIETARY EFFICIENCY AND METHANE PRODUCTION IN MUSKOXEN

James P. Lawler and Robert G. White
Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA

Methane is significant as a loss of dietary energy to ruminants and as a greenhouse gas. Since global climate change will affect plant distribution and change species dominance, it will undoubtedly affect ruminant diet choice which will have an affect on both the efficiency of energy use and total methane production by arctic ruminants. Estimates of global ruminant methane emissions could be in error when extrapolated to wild ruminants as they are based on studies involving domestic livestock fed graminoid-based diets. We hypothesize that wild ruminant diet choice has evolved to minimize methane loss; however, how well they can maintain efficiency in global change scenarios is not known. Muskoxen are ideal for this study because they live in an environment where energy efficiency is of paramount importance and they feed on a continuum of forages from grasses to browse species. Our research indicates that woody browse can influence energetics in muskoxen through its effect on methane production.