It was evaluated the effect of four regrowth ages (35, 49, 63 and 77 days) on leaf/steam relation, bromatological composition, productivity and in situ degradability of Andropogon grass (Andropogon gayanus Kunth.) during rain session. There was linear effect increasing (P<.01) of ages after regrowth for DM and ADF in plant and for NDF and ADF in leaves and decreasing for CP and MM plant. There was quadratic effect (P<.01) for NDF in the plant, CP in leaf and for leaf/stem relation. Productivity was influenced (P<.01), with increase of 38.8kg of DM for day after regrowth. DM and NDF potential degradability were high at 35 days after regrowth, in three incubation times, with decreases due to the increase of age of regrowth At 35 and 63 days after regrowth was verified the greater CP potential degradability. Effective degradation of DM was high at 35 days after regrowth, while for NDF higher values were obtained at 35 and minor to 77 days. Andropogon grass to 35 at 49 regrowth days, has higher potential degradability and effective degradability of dry matter, crude protein and neutral detergent fiber, due to better leaf/stem ratio associated with lower fiber content, and presenting 6 to 8% of protein content, enough to maintenance of ruminants.
Andropogon gayanus; bromatological composition; in situ degradability; tropical grass; productivity