FIBER ANALYSES OF AN EVERGREEN, A DECIDUOUS WOODY AND A NON-WOODY DICOTYLEDON - COMPARISON OF 2 TECHNIQUES

Forage fibre content is frequently used as an index of forage quality, where high fibre content indicates low forage quality. Although the a cid-detergent fibre (ADF) and acid-pepsin digestibility (AP) technique s have provided similar estimates of forage quality for a variety of h erbaceous monocotyledonous plants, these techniques have provided diss imilar estimates of fibre content for a willow, a deciduous woody dico tyledonous forage. This lack of correlation has been attributed to var iations in the proportions of stem and leaf material that comprised th e willow samples. Both the ADF and AP techniques were used to compare the estimates of the fibre content of willow leaves, willow stems, an evergreen ericaceous dwarf shrub, and a non-woody dicot. A strong nega tive correlation and a linear relationship were found between the fibr e content, as determined by ADF, and the digestibility, as determined by AP, for each sample type. The linear relationships were significant ly different for all sample types. This suggests that, although phenol ogical changes in Fibre content may differ between samples, the two te chniques provide a very similar estimate of forage quality in dicotyle donous forages. In the case of deciduous woody dicotyledons, leaf and stem material must be separated prior to the analyses.