The chemical composition, net energy values and protein digestible in small intestine of lucerne primary growth and regrowth samples were estimated by near infrared spectroscopy (NIRS) and by regression equations based on the days or accumulated temperature from the beginning of vegetation. Regression equations, predicting tested parameters for primary growth samples for one year, were obtained using the days of vegetation (DV) or the accumulated temperature (AT) as independent variables and tested with primary growth samples from the two other years. The prediction accuracy for these parameters by the established equations with both independent factors (DV or AT) was similar and enough for practical purposes. The NIRS calibration equations for the primary growth or the regrowth showed better or very close accuracy to that of the regression equations with AT or DV. The accuracy of prediction did not differ significantly for both growths. No significant differences in the standard error of prediction were found for samples of the primary growth and regrowth when they were analyzed by a general calibration equation including both growths. NIRS has an advantage since it is not necessary to observe the DV and AT and it is possible to analyze samples from different growths with general calibration.