IN-VITRO DIGESTION KINETICS OF NEUTRAL DETERGENT FIBER EXTRACTED FROMTIFTON-85 AND COASTAL BERMUDAGRASSES

Hays used to compare the digestion kinetics of neutral detergent fiber (NDF) were Tifton 85 bermudagrass (T85) harvested after 3.5 or 7 week s of growth, a second cutting of T85 harvested after 3.5 weeks of regr owth, and Coastal bermudagrass (CBG) harvested after 4 weeks of growth . Neutral detergent fiber extracted from the hays was exposed to in vi tro digestion and the digesta analyzed for their NDF content. The in v itro dry matter disappearance for the first (63.6%) and second (59.9%) cutting of 3.5-weeks old T85 was similar but higher than that for T85 harvested after 7 weeks of growth (48.7%) or CBG harvested after 4 we eks of growth (52.0%). In vitro NDF digestion at 72 h of incubation fo r T85 harvested at 3.5 week (74.5%) was similar to that of 3.5-weeks T 85 regrowth (67.4%), but higher than that of CBG (63.7%) or 7-weeks T8 5 (53.7%). After fitting a nonlinear model to the data, T85 harvested at 3.5 week had a higher (P<0.05) potentially digestible fraction of N DF. Extraction of NDF from the hays increased the potentially digestib le fraction of NDE In summary, Tifton 85 bermudagrass harvested at 3.5 week had a higher NDF concentration, and higher NDF digestion than di d Coastal bermudagrass harvested at 4 week. (C) 1998 Elsevier Science B.V.