Potential of crop residues and agricultural by-products for feeding sheep in a Gambian village

Abstract

The quantity and potential use of crop residues and agricultural by-products for feeding sheep were determined in a Gambian village. The crop residues present were millet and maize stover, rice straw and groundnut hay. The yield of crop residues was estimated by sampling quadrats which were randomly placed along transects in ten fields per crop. Agricultural by-products included millet bran, maize bran, rice bran, sesame cake and groundnut cake. Yields of agricultural by-products were determined by estimating the amount of crop which was processed in the village and directly measuring extraction rate. The nutritive value of crop residues and by-products was determined by the detergent systems of forage analysis. Most of the cereal crop residues were grazed in the field. Groundnut crop residue was harvested and stored for feeding livestock but only 47% of this hay was collected. Groundnut leaves contained high concentrations of crude protein and metabolizable energy, and the groundnut stems were higher in crude protein than all fractions of the cereal crop residues. Stored groundnut hay was of lower nutritive value than immediately after harvest, since substantial loss of nutrients occurred during harvest and storage. Millet bran was the most abundant by-product available in the village, and was higher in crude protein and metabolizable energy and lower in neutral-detergent fibre than either maize and rice bran. Rice bran had a low nutritive value because of contamination with hulls that contain high amounts of lignin and biogenic silica and are not removed before milling. The high content of ether extract in groundnut and sesame cakes indicated that the oil press used in the village was inefficient. Only 10% of the groundnut cake was available in the village because most of the groundnuts were sold to the government marketing board. The results indicated that the village has adequate quantities of crop residues and by-products to meet the feed requirements of improved sheep production systems. However, many production constraints exist and research and extension programmes for improved sheep production are needed. Simple diets for sheep based on available feed resources are presented.