Abstract
The dry matter (DM) yield and nutritive value of Setarla sphacelata, Digitaria setivalva, Pennisetum purpureum, Panicum maximum and Brachiaria decumbens were determined at 2-, 4-, 6-and 8-week cutting intervals (Cl) over a 3-year period. There were no significant differences in DM yield between grasses in the first harvest year, and only small differences in later yields. The DM yield in the second and third harvest years was approximately half that of the first year. The results showed that while 25-42 t OM ha-1 could be obtained from grasses cut at a 6-week interval in the first harvest year, 11-19 t ha-1 was a more typical yield in later years. Although there were significant differences in quality between grass species, these were small and of little practical importance when compared with the effect of Cl. Averaged over the 3-year trial, the in vitro DMD and crude protein (CP) concentration declined by 43 and 29 g kg-1 DM, respectively; crude fibre (CF) increased by 26 g kg-1 DM for each 2-week increase in Cl. For each grass a highly significant relationship existed between the in vitro DMD and concentration of CF, CP, CF/CP, and CF/CP ash (g kg-1 DM).
