Fermentation kinetics of Brachiaria brizantha cv Marandu harvested on 28, 56, 84, and 112 days of growth was evaluated with the semi-automatic in vitro gas production technique. Regression equations between volume of gas and dry-matter digestibility during fermentation periods of treatments were linear. Marandu grass harvested on 28 and 56 days of growth showed the greatest rate of gas production around 18 hours of incubation, while the rate of gas production of forages cut at 84 and 112 days reached the peak at 36 hours of incubation. Cumulative gas production was higher on 28 and 56 days of harvest intervals than grass harvested on 84 and 112 days. Therefore, the best harvest stage for using Brachiaria brizantha cv Marandu were between 28 and 56 days due to highest ruminal fermentability.
grass; gas production; nutritive value
