Growth performance, nutrient digestibility, nitrogen utilization and economic efficiency of West African dwarf rams fed rice straw, maize stovers or maize cobs.

Abstract

This study evaluated the effects of rice straw, maize stovers, and maize cobs supplemented with poultry-litter-based concentrate on feed intake, growth performance, nutrient digestibility, nitrogen utilization, serum metabolites, and economic efficiency of West African Dwarf (WAD) rams. Twenty-four rams were allotted to three dietary treatments, with each crop residue offered as the basal feed and supplemented with a common concentrate containing 20.8% crude protein and 10.5 MJ/kg DM metabolizable energy. Significant differences (P < 0.05) were observed among treatments for feed intake, growth performance, nutrient digestibility, nitrogen utilization, selected serum metabolites, and economic returns. Rams fed maize stovers had the highest dry matter intake (910 g/day), final body weight (27.8 kg), weight gain (9.2 kg), and average daily gain (132 g/day), compared with 780 g/day, 24.2 kg, 5.8 kg, and 82 g/day for rice straw and 720 g/day, 23.5 kg, 5.0 kg, and 71 g/day for maize cobs, respectively. Feed conversion ratio was lowest with maize stovers (6.89). Maize stovers also produced the highest dry matter (68.4%), crude protein (70.2%), and neutral detergent fibre (59.6%) digestibility. Nitrogen retention was greatest in maize stover-fed rams (9.2 g/day; 62.1%). Serum total protein, albumin, and glucose were higher with maize stovers, whereas serum urea and cholesterol were unaffected. Maize stovers had the highest net profit (USD 38.4) and benefit-cost ratio (1.61), with the lowest cost per kilogram of gain (USD 1.08). Thus, maize stovers supplemented with poultry-litter-based concentrate provided superior biological and economic performance and represent a promising basal feed resource for WAD rams.