DIGESTIVE RESPONSES OF WAPITI CERVUS-ELAPHUS CANADENSIS TO SEASONAL FORAGES

we tested the hypothesis that seasonal differences in passage rate and digestibility of native forage in wapiti Cervus elaphus canadensis Er xleben, 1777 were due to seasonal appetence and digestive adaptation a s well as plant phenology and composition. To this end, we compared di gestive characteristics of seasonal pasture with those of a standard a lfalfa-barley pellet fed to wapiti hinds throughout the year. No evide nce of seasonal effects independent of forage quality was found. Altho ugh dry matter intakes differed 2-3 fold, the digestibility of the sta ndard pelleted diet was not significantly different in winter (0.68 +/ - 0.02), spring (0.74 +/- 0.01) and summer (0.71 +/- 0.01). However, d igestibilities of natural forages increased greatly from winter (0.51 +/- 0.01), to spring (0.77 +/- 0.02), with a gentle decline into autum n (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 speci fic seasonal adaptation. The mean retention time of winter herbage (41 +/- 2 h) was significantly longer than that of spring (28 +/- 3 h) an d summer (25 +/-2 h) forages. Pasture forages were retained longer (51 +/- 1 h) than pellets in winter but not in spring (28 +/- 1 h) and su mmer (27 +/- 1 h). Fecal moisture was a good indicator of digesta rete ntion time despite forage type and may provide a simple index of diges tive function for field studies.