Prediction of yield and digestibility of Napier grass (Pennisetum purpureum) from maturity, leaf: stem ratio and laboratory analyses

Abstract

Napier grass (P. purpureum) was grown at Naivasha, Kenya. Weekly data on various parameters of Napier grass on-station (irrigated) and on-farm (rain-fed) were pooled and assessed by linear and quadratic regressions. The dry matter (DM) yield could be accurately estimated using age or height whereas in vitro organic matter digestibility (OMD) was predicted better from cell-wall fractions and crude protein content. Prediction of DM yield was more accurate than that of in vitro OMD. Multiple regression equations accounted for more variations in DM yield, in vitro OMD and in vivo digestible organic matter than equations derived from single independent variables. Some of the regression equations could accurately predict DM yields and in vitro OMD at different years on-station. However, prediction of DM yield on-farm was less accurate and possible only for the high rainfall districts.