Seasonal Variations of the in vitro Dry-Matter Digestibility of Three Sandhill Grasses

Investigation of the seasonal variation of in vitro dry-matter digestibility of forage of three range grasses was completed. The in vitro dry-matter digestibility declined in all grasses with advance in maturity. Crude protein content declined with advance in maturity and was more highly correlated with dry-matter digestibility than was lignin. Predicted digestibility based on Van Soest's summative equations seemed unrealistically high for forage collections made in late season. No consistent or significant variations in cell-wall constituents or acid-detergent fiber were measured.