Abstract
Two tall and four dwarf napiergrasses (Pennisetum purpureum Schum.) were evaluated at three cutting intervals (CI) and at two locations. Overall dry matter yield (DMY) means of Merkeron and Merker (tall grasses) at the 45-, 65-, and 85-d CI (37.5, 48.8 and 52.8 t/ha/yr, respectively) were significantly higher (P = 0.05) than those of the dwarf grasses. Average DMY of the grasses increased 15% (P = 0.05) from the 45- to the 65-d CI. Overall mean crude protein concentration (CPC) of N75 and N127 (dwarf) at the 45- and 65-d CI surpassed (P = 0.05) those of the tall and most of the other dwarf grasses. In most instances the crude protein yield (CPY) of Merkeron and Merker exceeded (P = 0.05) those of the dwarf grasses. Merkeron and Merker plant heights (P = 0.05) were greater at all three cutting intervals. N75 (45-d CI), and N75 and N127 (65- and 85-d CI) had superior (P = 0.05) mean leaf:stem ratios. No difference (P = 0.05) in terms of in vitro dry matter digestibility (IVDMD)were observed among the six Pennisetums. The results of this study suggest that Merkeron and Merker could be recommended for use under cutting management and the dwarf grasses, especially N75 and N128, for grazing.