Studies in the Digestibility of Herbage

Data from 291 digestion trials have been used to derive regression equations relating the organic‐matter digestibility of herbage to the nitrogen percentage of its dry matter and to the nitrogen percentage in the organic matter of the resulting faces. The residual errors are very high and it is shown that the deviations from the lines are not randomly distributed but have a seasonal trend. The seasonal biases have been calculated, and the inclusion of month of cutting as a factor is found to improve the two regressions to some extent. Monthly regressions have also been calculated. Even with these, however, the errors are still too high for many practical purposes.