Study of rumen degradation kinetics of cell wall components of concentrate feeds and agroindustrial by-products

Abstract

This study was the synthesis of rumen degradation measurements of cell wall components (NDF, ADF, ADL) using the Nylon bagmethod applied to 217 samples of about 80 concentrate feeds and industrial by-products. This data set is the more complete publishedcollection of results obtained using a homogeneous methodology. The degradation dynamics of the feeds was evaluated usingpara6meters of two non-linear adjustment models, the Ørskov and McDonald model (1979) and the Mertens model (1973), takinginto account (or not) a lag phase at the onset of the degradation. These parameters showed large within- and between-feed variations,closely related to the quality of the cell wall and especially to the importance of its lignified fraction. Moreover, the influence ofthis criterion strongly differs from a family of food to the other. This work led to the development of a coherent table for degradationparameters of cell wall constituents which will make it possible to improve the feed unit systems for ruminants and could beintegra6ted in modelling studies on rumen digestion.