ENSILING CHARACTERISTICS AND NUTRITIVE VALUE OF GUINEA GRASS (Panicum maximum, Jacq.) AS AFFECTED BY GROWTH STAGE

An experiment was conducted to study the effect of frequency of defoliation on the ensiling characteristics and nutritive value of Guineaecotype 'A' (Panicum maximum Jacq) grass. Guinea grass harvested at 2, 3, 4, 5, 6, 7, 8, 9, 10 and 12-week cutting intervals was chopped (2 cm) and ensiled alone or with the addition of coconut (Cocos nucifera L.) meal (w/w-fresh weight basis), for periods of 6, 7 or 8 weeks in 2-litre laboratory silos. Dry matter, water soluble carbohydrates, lactic acid, pH, ash, nitrogen and digestibility in vitro were measured in representative samples of preensiled and ensiled material. Dry matter content of silages prepared from herbage harvested at 2 and 3 weeks intervals was lower (P<0.05) compared to longer defoliation intervals. The pH of silage prepared from herbage over 8 weeks old were higher (P<0.05) than those harvested below 8 weeks. The water soluble carbohydrate content of silage prepared from 3-weekly defoliated herbage was higher (P<0.05) than those prepared from longer periods. Lengthened growth period decreased (P<0.001) the crude protein content of the ensiled material, whereas the addition of coconut meal resulted in marginal increases. In vitro organic matter digestibility of the silages decreased (P<0.05) with the increase in forage maturity.