Avaliação nutricional de fenos de Andropogon gayanus cv. Planaltina produzidos em diferentes idades de crescimento

Abstract

In this research was evaluated nutritional value of Andropogon gayanus cv. Planaltina hays produced at different ages of growth (56, 84, 112 and 140 days). In experiment 1, the dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations increased lineally, while that crude protein (CP) content and in vitro dry matter digestibility (IVDM) decreased quadratically, the lignin increased quadratically with advanced age of the forage. In experiment 2, the in situ degradability of dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF); and in experiment 3, the in vitro degradability dry matter were compared by tests of parallelism and identify of curves. The parallelism test didn’t demonstrate difference between the curves of the in situ degradation to dry matter, neutral detergent fiber, acid detergent fiber and in vitro dry matter degradability. Therefore, the different ages of growth showed the same behavior of kinetic degradation. However the curves of identification test demonstrated that equations for A. gayanus hays cutted at 56 and 84 days of growth were identical and different than other ages of cut. These ages of growth showed high degradation in situ for DM, NDF, ADF and in situ dry matter degradability. The A. gayanus hays produced between 56 - 84 days of growth of forage showed the better nutritional responses.