Effect of cutting interval and season on forage yield and chemical composition of Brachiaria brizantha (A. Rich.) Staff in Yucatan, Mexico

Abstract

The present study was aimed to evaluate the effect of eight cutting intervals (i.e. 1, 2, 3, 4, 5, 6, 7 and 8 weeks) and three seasons (i.e. dry, rainy and late-rainy seasons) on Brachiaria brizantha growth rate, forage yield and chemical composition. Treatments were arranged as a split plots within a completely randomized design on an eight-year old B. brizantha pasture. It was found that, forage yield, growth rate and leaf proportion were affected (P<0.05) by season, cutting interval and their interaction. The greater yield and the highest growth rate, 3.78 t DM ha-1 and 121.6 kg DM ha-1 day-1, were registered in the rainy season at the eight-weeks cutting interval. The lowest forage yield and growth rate, 0.02 t DM ha-1 and 2.28 kg DM ha-1 day-1, were recorded at one-week cutting interval in the late-rainy season. The extreme values of leaf percentage, 81, 77 and 90, and 63, 91 and 76, were found at one-week and eight-week cutting intervals for the dry, rainy and late-rainy seasons, respectively. In the rainy season, crude protein (CP) was reduced 0.96% per week starting from the five-week cutting interval. However, in the dry and late-rainy seasons, CP was maintained above 7 % at all cutting intervals. Nevertheless, contents of CP were reduced and fibre increased at the longest cutting intervals, except the lignin content which was not affected neither by the cutting intervals nor the season evaluated.

Keywords

• brizantha
• age
• growth rate.