山羊

To investiga te the influence of reticulo-ruminal movements on dry matter disappearance (DMD) of tropical grass in the rumen of goat， an experiment measuring DMD of leaf and stem of Rhodes grass (Chloris gayana) was conducted using nylon bag in the rumen of goat or in vitro incubation with rumen fluid of the goat. DMD in the rumen in 48 hr was measured with chopped (about 3 cm in length) materials and in vitro DMD in 48 hr was measured with chopped and ground (1 mm) materials. The authors regarded DMD of chopped materials in the rumen as DMD with reticulo・ruminalmovements and in vitro DMD of chopped materials as DMD without reticulo・ruminal movements. In addition， comparing in vitro DMD of chopped materials with that of ground materials， the authors discussed the effect of mastication on DMD of mature tropical grasses. The resuIts obtained were as follows: 1. There was little difference between DMD of chopped materials in the rumen and that with in vitro incubation. Therefore， reticulo・ruminal movements seemed not to play an important role in DMD of chopped materials of Rhodes grass in the rumen of goat. 2. In vitro DMD of ground materials was higher than that of chopped materials. The difference in DMD between ground and chopped materials became larger with the increase of lignin content of the materials，and the result supported the effect of mastication on DMD of mature tropical grasses.