We tested the hypothesis that seasonal differences in passage rate and digestibility of native forage in wapiti Cervus elaphus canadensis Erxleben, 1777 were due to seasonal appetence and digestive adaptation as well as plant phenology and composition. To this end, we compared digestive characteristics of seasonal pasture with those of a standard alfalfa-barley pellet fed to wapiti hinds throughout the year. No evidence of seasonal effects independent of forage quality was found. Although dry matter intakes differed 2-3 fold, the digestibility of the standard pelleted diet was not signficantly different in winter (0.68 ± 0.02), spring (0,74 ± 0.01) and summer (0.71 ± 0.01). However, digestibilities of natural forages increased greatly from winter (0.51 ± 0.01), to spring (0.77 ± 0.02), with a gentle decline into autumn (0.65 ± 0.02). Because retention times of pelleted diets were not significantly different among seasons (winter 28 + 1 h, spring 24 ± 2 h, summer 22 ± 1 h), digestive kinetics also seemed to be mainly a function of seasonal composition of native forage rather than specific seasonal adaptation. The mean retention time of winter herbage (41 ± 2 h) was significantly longer than that of spring (28 + 3 h) and summer (25 ± 2 h) forages. Pasture forages were retained longer (51 ± lh) than pellets in winter but not in spring (28 ± 1 h) and summer (27 ± 1 h). Fecal moisture was a good indicator of digesta retention time despite forage type and may provide a simple index of digestive function for field studies.
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