Evaluation of quality characteristics in official trials with silage maize varieties in Belgium

Abstract

Digestibility of >550 silage maize cultivars in official Belgian trials was analysed using the near infrared reflectance spectroscopy (NIRS) method based on an in vitro method with cellulase. Comparison of results with this method with those from a NIRS method based on an in vitro method with rumen fluid of fistulated sheep showed a highly significant correlation. However, after each new harvest a certain percentage of the samples should be analysed in a classical way to validate the calibration equation against a sample set with new genetic material. In contrast to previously reported studies, there was no clear tendency for NIRS to overestimate the digestibility of early cultivars or underestimate that of late cultivars. The results of NIRS starch analyses showed a significant correlation between earliness and starch content. Since digestibility and starch are not well correlated, the incorporation of starch as a new criterion is valuable and it can give additional information about the net energy content of silage maize cultivars.