In vitro Digestibility of South Texas Range Plants Using Inoculum from Four Ruminant Species

Abstract

Differences in the in vitro digestible dry matter (DDM) of 26 native forage species in south Texas were determined using rumen inoculum from white-tailed deer, sheep, goat, and steer. The mean DDM of all forages was significantly different for each animal species (P<.05). Deer was the most efficient overall digestor of forbs, shrubs, and prickly pear. Of the grasses sampled, the goat was the most efficient digestor with the steer second. In overall efficiency of digestion of all forages tested, the deer was highest with 52.5%, goat with 49.2%, sheep with 47.5%, and steer with 46.6%. These data indicate that caution should be exercised when using inoculum from one ruminant species to estimate DDM for another species. Certain plant species were determined to meet the TDN requirements for maintenance levels of the four ruminants.