The aim of the work was to determine the differences between portable pNIR (in the original mass) and chemical analysis in 4 maize hybrids, 4 years. Main conclusions: (a) Nutritional values determined by pNIRS compared to chemical analysis were higher (P < 0.001) in starch and ash content, but lower in dry matter, NDF and crude protein content. (b) Neutral detergent fiber digestibility (NDFD) and NEL levels were also lower, as well as potential milk production per hectare in relation to each tonne of dry matter. (c) The standard deviation of pNIRS values was mostly lower than that of chemical values. (d) Correlation between pNIRS and chemical results was found to be significant (P < 0.05) for all indicators. (e) According to the determined results, it is necessary to calibrate all the tested indicators for the given spectrometer.