Determination of indigestible neutral detergent fibre contents of grasses and its prediction from chemical composition

Five grass species (Dactylis glomerata, Phleum pratense, Lolium perenne, Festuca arundinacea and the hybrid Felina (Lolium multiflorum x Festuca arundinacea)) were harvested at different maturities of primary growth (n=60) and evaluated for contents of dry matter, crude protein, ash, crude fat, neutral detergent fibre, acid detergent fibre, acid detergent lignin (ADL), indigestible neutral detergent fibre (INDF) and digestible neutral detergent fibre (DNDF). INDF and DNDF concentrations were determined by in sacco rumen degradation of grasses for 12 days in non-lactating cows. ADL concentration was found to be significantly correlated with DNDF (r=-0.87) and presented a reliable (R2=0.78; residual mean square error of 17.65 g/kg DM; P less than 0.0001) parameter to predict INDF concentrations. Over a six-week period of maturation INDF concentrations increased (P less than 0.0001) in all studied grasses. It was confirmed by this study that the INDF concentrations of grasses could be effectively predicted from ADL concentrations.