A comparison of ten rice-straw varieties grown at two different altitudes during a wet and a dry season, using the in vitro cumulative gas production technique

In vitro cumulative gas production was used to evaluate a series of rice straws for their fermentability. The straws comprised ten different varieties which had been grown at two locations (higher and lower altitudes), during two seasons (wet and dry). Curves were fitted, and the resulting parameters, DM loss and gas yield, were tested for significant differences by an analysis of variance using the Tukey test. Significant differences between the parameters of the fitted curves were found between the offered and refused straw, the material grown at different altitudes, the material from the wet and dry seasons, and between varieties. Significant interactions were found between the environmental factors and cultivar, for the offered and refused feeds.