In vitro digestibility of forages by coexisting deer species in Texas

Percent in vitro digestible dry matter (IVDDM) of seven forages was estimated using rumen inocula from three fallow deer (Dama dama), two sika deer (Cervus nippon) and two white-tailed deer (Odocoileus virginianus) from the Edwards Plateau region of south-central Texas, 4-5 November 1987. Deer species source of inoculum affected lVDDM (P < 0.1) for four of seven forage species. Estimates of IVDDM for common curly mesquite (Hilaria belangeri), Texas wintergrass (Stipa leucotricha) and plateau live oak (Quercus virginiana fusiformis) were higher (P < 0.1) for sika deer than for fallow deer and white-tailed deer. This suggests that lVDDM results using rumen inoculum from a particular herbivore species should be applied with caution to other herbivore species. These results support the hypothesis that sika deer have a competitive advantage over white-tailed deer where these forages constitute a significant part of the diet, due to their ability to more completely digest these common range forages when highly digestible forages are limited.