Forage Fibre Analyses: a Comparison of Two 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 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 (Carex atherodes, C. aquatilis, Phalaris arundinacea, Calamagrostis spp., Agropyron trachycaulum [Elymus trachycaulus] and Hordeum jubatum) 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 Salix spp. and lichen showed a poor correlation between techniques, suggesting dissimilar estimates of fibre content of these forages.