FORAGE FIBER ANALYSES - A COMPARISON OF 2 TECHNIQUES

Forage fibre content is frequently used as index of forage quality where high fibre content indicates low forage quality. Fibre content is usually estimated by the familiar acid-detergent fibre (ADF) technique. An alternative method, the acid-pepsin digestibility (AP) technique, provides an estimate of forage digestibility where low digestibility indicates a high fibre content. Fibre content estimates in herbaceous forage were compared by the ADF and AP techniques. There was a strong negative correlation between the fibre content, as determined by ADF, and the digestibility, as determined by AP, in a wide variety of herbaceous forages. This suggests that both techniques provide a very similar estimate of forage quality in herbaceous forages. Contrastingly, a similar analysis on willow and lichen showed a poor correlation between techniques, suggesting dissimilar estimates of fibre content of these forages.