Predicting feeding value of forage maize hybrids harvested at different maturities and sites

Abstract

The objective of this study was to evaluate two near-infrared reflectance spectroscopy (NIRS) applications and different laboratory methods for determining indigestible neutral detergent fibre (iNDF) and organic matter digestibility (OMD) of forage maize hybrids harvested at high latitudes. Different in situ and in vitro methods have been used in calibrations of NIRS for routine determinations of forage feed value in the Nordic countries. Swedish and Finnish NIRS calibrations of iNDF generated biased estimates of low precision of iNDF determined in situ. All methods used to predict OMD in forage maize systematically underestimated the observed OMD calculated from the in situ determined value of iNDF. Digestibility was determined with least precision based on the enzymatic in vitro procedure. Values of OMD based on the in vitro incubation in buffered rumen fluid displayed the smallest error among the laboratory methods. The NIRS calibration developed with the forage maize samples of this study, suggested that NIRS has a great potential to predict iNDF and OMD of forage maize accurately and precisely. It was concluded that NIRS predictions of OMD can be a promising tool for evaluating performance of forage maize hybrids at high latitudes if NIRS calibrations of iNDF including forage maize samples are available.