Nutritive evaluation of the natural pastures at early and late rainfall season in Kordofan and Butana, Sudan.

2Absract: This study to assess the nutritive value of some plant species, in Kordofan and Butana natural pasture during early and late rainfall season in terms of chemical composition and relative feed value (RFV).Thirty four plant samples (forbs, shrubs and grasses) from natural pasture at Kordofan (western Sudan) and Butana (eastern Sudan) seventeen each, were evaluated during early and late rainfall season in terms of chemical composition, crude protein (CP), ether extract (E.E), Ash, silica, neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). Relative feed values (RFV) were calculated used NDF and ADF contents. In the two locations a significant (p<0.001) differences were observed in chemical composition due to species. The highest CP observed in forbs particularly A. viridis followed by T. terrestris 25.5 % and 23.7 % respectively at early season in Kordofan, while T. terrestris showed the highest CP content followed by A. viridis 25 % and 23.6 % respectively in Butana. CP, Ash and silica decreased while NDF, ADF and ADL were increased significantly (p<0.001) at late season in most of plat species. Forbs and shrubs had significantly (p<0.001) higher CP and ADL than grasses. High Ash (p<0.001) and high silica (p<0.05) were observed in forbs compared to both shrubs and grasses. RFV were adversely reduced in most grass species and significantly (p<0.001) decreased at late season because of increasing NDF and ADF. Forbs were ranked as high feed quality followed by shrubs as medium and grasses as low feed quality with average values 104.6, 92.1 and 81.5 respectively. Pasture in Kordofan had higher CP, Ash, silica and ADL and lower NDF compared to the pasture in Butana. The low NDF in Kordofan resulted in relatively high RFV which may be restricted by high ADL and silica contents as anti herbaceous. Pasture in the both locations had relatively high CP i n early season sufficient for animal requirements, that will become insufficient at late season only if grasses been predominant because grasses had drastic low CP content at mature stage. Advance study on legume / grass ratio through the rainfall season was required.