Chemical and in vitro digestion proceduces for the prediction of the digestibility of forage crops by sheep
Osbourn, D.F.; Terry, R.A.; Outen, G.E.; Cammell, S.B.; Lansley, P.R.
Proceedings of the Nutrition Society 30(3): 85A-86A
1971
ISSN/ISBN: 0029-6651 PMID: 5154133 Document Number: 31563
Digestibility of 54 timothy, perennial ryegrass, Italian ryegrass, sainfoin, whole-crop maize and red clover herbages was determined in vivo with wether sheep and in vitro (a) with high precision using the 2-stage digestion procedure of Tilley and Terry, (b) with reasonable reliability by Van Soest's 2-part prediction equation based on chemical analysis of herbage and (c) with low precision by Van Soest's simple determination of the content of lignocellulose measured as the material insoluble in acid detergent solutions (ADF) . It was concluded that using the equations DMD = 0.96 CC-11.1 + NDF (1.312-0.635 log.ADL x 100/ADF) and D-value = 1.01 CCA-10.5 + NDFA (1.353-0.654 log.ADL x 100/ADFA) where DMD = DM digestibility, CC = cell contents, NDF = cell-wall constituents, ADL = acid-insoluble lignin, CCA = ash-free estimate of CC, NDFA-ash-free estimates of NDF and where ADFA = ash-free estimate of ADF, as an alternative to measurements in vitro, was more precise than prediction based on (c).