Abstract
The relationships between the contents of chemical constituents and their digestibility, dry matter digestibility, digestible cell wall fractions and digestible cell contents were examined using grasses grown in three different seasons. Among the contents and digestibilities of crude fiber, cell walls (CW) and acid detergent fiber (ADF), significant correlations were observed with first cutting grasses in spring, whereas, aftermath growth in summer and autumn had little correlation between them. Nonsignificant correlations were obtained between digestibility of carbohydrate and contents of the structural carbohydrate with the aftermath in summer. The contents of acid detergent lignin (ADL) and ADL+silica gave high negative correlations with digestibilities of carbohydrate and dry matter throughout the three seasons. The relationships between the contents of CW, ADF, ADL, silica, ADL+silica, ADL/ADF on the one hand and digestibility of CW and cell contents, their digestible amount, their indigestible amount on the other hand were determined. Seasonal effects on these relationships were observed.
