ASSESSING WINTER DIETARY QUALITY IN BIGHORN SHEEP VIA FECAL NITROGEN

Fecal indicators of nutritional status of wild ungulates are less cons trained than blood or urine analyses. Thus, we assessed the potential for fecal nitrogen concentration to predict winter dietary quality for Rocky Mountain bighorn sheep (Ovis canadensis) in Wyoming. Dietary ni trogen concentration and percent in vitro dry matter digestibility inc reased linearly with increases in fecal nitrogen concentration for han d-plucked diets of wild sheep on 4 winter ranges and for tannin-free d iets fed to 3 penned adult female bighorn sheep (2 were 1/8 mouflon [O . orientalis]). A linear regression developed from field samples gathe red in 2 winters accurately predicted winter dietary nitrogen concentr ations using fecal nitrogen levels from other winters. Fecal nitrogen concentrations differed (P < 0.0001) among 7 winter ranges. Our data s uggest that fecal nitrogen concentrations < 1.3% may identify winter d iets that are deficient in protein and energy for bighorn sheep.