Effect of season on the chemical composition and in vitro digestibility of some browse and shrubs in Ghana

Abstract

The seasonal variation in the chemical composition of some browse and shrubs in the coastal savanna of Ghana was ascertained. The browse studied were Antiaris africana, Delonix regia, Milletia thonningii, Grewia carpinifolia, Ritchea reflexa, and Securinega virosa. Samples collected in mid-November1992, early February 1993, and mid-June 1993 corresponding to the peak periods of the minor rains, dry season, and major rains, respectively, were used. Samples were analysed for dry matter and crude protein (percent CP), neutral detergent fibre (percent NDF), acid detergent fibre (percent ADF), cellulose, acid detergent lignin (ADL), and in vitro dry matter digestibility (IVD). Significant differences were observed with season (P<0.05) but not with species (P>0.05) with dry matter where the dry season values were higher than those of the major and minor rains. Dry matter content ranged between 33 and 40 per cent. Crude protein content was lower (P<0.05) in the major rains compared to the minor rains and dry seasons. It showed significant species (P<0.05) variation and ranged between 11and 22 per cent. No significant seasonal effects (P>0.05) were observed in the fibre components and IVD values, but significant species differences (P<0.05) were observed. The range of values were NDF 27-63, ADF 13-46, cellulose 10-31, ADL 2.5-41, and IVD 40-80 percent. Thus, browse and shrubs in Ghana have adequate protein levels that would make their contribution towards improving the dry season nutrition of ruminants very useful.



Ghana Jnl agric. Sci. Vol.31(1) 1998: 99-105