NIRS Estimation of the Nutritive Value of Megathyrsus maximus (Syn. Panicum sp.) Forages

Abstract

Aimed to evaluate the estimation of the nutritive value of Megathyrsus maximus (Syn. Panicum sp.) forages by near-infrared reflectance spectroscopy (NIRS). The experimental design was completely randomized with four replications. The treatments were arranged in a split-plot arrangement, with nine cultivars of M. maximus in the main plot (Aries, Atlas, Massai, Mombasa, Paredao, Kenya, Tamani, Tanzania, and Zuri) and four harvesting ages in the subplot (30, 60, 90, and 120 days). The contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF), indigestible neutral detergent fiber (iNDF), and ash were evaluated. A reduction in CP and ash contents is observed with the advancement of age in all evaluated cultivars. In contrast, an increase in DM, NDF, ADF, and iNDF contents is observed. The nutritive value of the forages from the evaluated cultivars deteriorates as age increases, recommending grazing periods of less than 60 days for cattle. The NIRS estimations are excellent (R2cv > 0.95) for CP, ash, NDF, and iNDF, demonstrating the potential of this technology for analyzing the nutritive value of M. maximus forages.