DETERMINING PRODUCTION AND NUTRITIVE VALUE OF CROP RESIDUES AND AGRO-INDUSTRIAL BY-PRODUCTS AND IMPROVING THEIR UTILIZATION IN RUMINANT NUTRITION IN ERITREA

Abstract

Livestock production plays important social and economic roles in Eritrea accounting for approximately 12.0% of the Gross Domestic Product. Despite the importance, animal productivity is low. This is attributed to poor quality feed characterised by fluctuations in quality and quantity within seasons and between years. Crop residues are an alternative feed resource that needs consideration for use in providing nutrients, however, there is need to determine the annual crop residues and agro-industrial by-products output, their respective chemical composition and nutritional values. Therefore, the overall aim of this study was to contribute to improved livestock production throughout the year in Eritrea through utilization of crop residues and agro-industrial by-products. The quantity of crop residues produced annually was estimated based on an eight years dataset (2007-2015) on the relevant crop production in five administrative zones of Eritrea. The chemical composition and degradation kinetics of nine cereal and seven legumes crop residues and seven agro-industrial by-products was determined.Crop residues were treated with urea and rations were formulated. Feeding trial was conducted using growing ram sheep. Findings indicated that approximately 1.3 million tonnes of crop residue is produced in Eritrea annually. Further analysis of the data obtained indicated that the crop residues accounted for 9.63 to 36.31% of the total annual maintenance feed requirements of the grazing ruminants. The contribution varied according to the land size set aside for crop production. Besides the crop residue the total amount of the agro-industrial by-products were estimated at between 19,604-19,788 tonnes and mainly comprised of brans, oilseed cakes and brewers grains.Generally, there was more (P<0.05) CP, ADL, ME and low (P < 0.05) NDF and ADF in legume straws with the exception for ADL in GNS than in cereal crop residues. The legume straws had higher value of degradability characterstics than cereals stover/straws. The nutritive value criteria were generally high in the agro-industrial by-products than in crop residue. Treating the crop residues with urea and/or supplementing with legume residues resulted in an increase in performancy of the sheep body weight gain in the growing lambs. Findings from this study indicate that crop residues and agro-industrial by-products hold huge potential in grazed animal feeding and/or supplementation in Eritrea Keywords Chemical Composition, Nutritional Value, Crop Residues, Agro- Industrial By-Products