Calculation of rumen degradation characteristics of residual non-starch polysaccharides of feedstuffs

Summary

The DVE/OEB-2007 protein evaluation system for ruminants requires estimating fermented residual non-starch polysaccharides (RNSP) in the rumen to determine microbial protein synthesis and the availability of this microbial protein in the small intestine. RNSP, comprising various non-NDF polysaccharides, is calculated, not measured directly, accumulating errors from other fractions. Fitting of RNSP fermentation data is challenging due to inconsistent degradation patterns. Unlike RNSP, NSP and NDF degradation generally increase steadily over time, aiding curve fitting. Analysis of rumen incubation data of various feedstuffs shows a substantial variation in RNSP fermentation across incubation periods. It is proposed to calculate rumen fermentable RNSP as the difference between rumen fermentable NSP and NDF and applying microbial protein efficiency for starch fermentation to RNSP, given their similar fermentation characteristics.