IN-VITRO DIGESTIBILITY STUDIES OF SOME LOCAL AND HIGH-YIELDING VARIETIES OF RICE STRAW (ORYZA-SATIVA)

Five local and four high-yielding varieties (HYV) of rice straw (Oryza sativa) were analysed for their various chemical constituents. The HYV rice straw samples were found to contain more glucose and xylose residues and less crude protein than those of the local varieties. Ash and silica contents were high in both groups. Extensive in vitro rumen digestibility studies showed that the HYV rice straw generally had higher dry matter disappearance (DMD) and organic matter disappearance (OMD) values compared with the local varieties. The in vitro rumen degradation patterns of cellulose, hemicellulose and bound p-coumaric and ferulic acids in rice straw cultivars 'BR14' and 'Balam' were similar. Klason lignin degradation was low in both the samples. Alkali treatment increased the DMD and OMD values of all the samples by an average of 14% and 15%, respectively.