Reliability of Captive Deer and Cow In Vitro Digestion Value in Predicting Wild Deer Digestion Levels

Abstract

The in vitro dry matter digestibility (IVDMD) values of 9 forages were compared using rumen fluid collected from wild white-tailed deer (Odocoileus virginianus), captive white-tailed deer, and a Holstein cow. Five of the 9 forages analyzed displayed significantly different (P<0.05) IVDMD between wild deer and captive deer inocula and between wild deer and cow inocula. Differences were attributed to the diet differences of the donor animals, which may have influenced the composition of microorganisms within the rumen. In vitro dry matter digestibility of all 5 forages considered together decreased significantly (P<0.05) when rumen inocula were stored at various intervals. This study indicates that IVDMD values obtained using inoculum from captive and domestic animals on commercial diets should only be used by researchers to make comparisons of forages, not to predict actual digestibility levels by wild animals. In addition, in vitro samples should be inoculated as soon after collection as possible in order to obtain reliable data.