Development of near infrared (NIR) spectroscopy and electronic nose (EN) techniques for analysing the conservation quality of farm silages.

Near infrared (NIR) spectroscopy methods are now widely used in animal science to predict the chemical composition of forages and other foods, including silage. NIR is a convenient and rapid alternative to chemistry methods, which are expensive and time consuming. However, silage analysis using NIR has so far been limited to oven-dried samples, because volatile compounds are lost during the drying process. The development of NIR techniques for fresh silage would improve efficiency by eliminating the drying and grinding processes and would prevent volatile losses. The aim of this study was to examine the feasibility of predicting fermentation characteristics in fresh silage using an NIR spectrometer or an electronic nose. Silage samples were taken from 19 Italian stock farms and were analysed for dry matter (DM), pH, buffering capacity (BC), total N, soluble N, ammonia N, alcohols, lactic acid and volatile fatty acids (VFA). The wide range of variation observed in the conservation quality seemed adequate to cover a wide variation in Italian farm silages. NIR analyses of the 33 silage samples were carried out with a Lab-SPEC PRO (ASD) in a 350-2500 nm spectral range......