Dwarf elephantgrass under crazing II. Nutritive value

Abstract

Dwarf elephantgrass (Pennisetum purpureum Schum.) was evaluated in a grazing trial. Grazing pressure (GP) and grazing cyle (GC) were applied at five levels: GP-500, 1,000, 1,500, 2,000 and 2,500 kg of residual leaf dry matter ha^-1 after grazing and CG - 0 (continuous grazing), 14, 28, 42 and 56 days. The GC included a 2-day grazing period plus a specific rest period. A nonrotatable central composite design with 13 treatment combinations in two replications was used. A complete second - order polynomial model was used to analyse the data. The crude protein of leaves and stems increased as GP was increased and GC was shortened. The in vitro, digestibility of leaves, stems and "grazed forage" seemed to be affected quadraticaly by GC. Heavier GPs tended to favour the digestibility of stems. The crude protein of "grazed forage" was increased by shorter GCs. The optimum point for digestibility of "grazed forage" was around GP of 1,500 kg of residual leaf DM ha^-1 and 14 days of GC. Leaves had higher nutritive value than stems and the high quality of "grazed forage" revealed the potential of this grass under grazing.