Urea-ammoniated cowpea husk in goat diet: Feed utilisation, ruminal fermentation, nutrient digestibility, nitrogen utilisation, blood metabolites and growth performance

Abstract The study investigated the effect of urea-ammoniated cowpea husk (UCH) as a substitute for dried brewers’ grains (DBG) on voluntary intake, ruminal fermentation, apparent digestibility, nitrogen retention, serum metabolites and growth performance of eighteen growing Red Sokoto goats. Goats were stratified into three groups: no UCH (control), 350 g/kg UCH and 700 g/kg UCH replacing 0, 500 and 1000 g/kg of DBG respectively. Average daily gain, organic matter (OM) and acid detergent fibre digestibility, digestible OM, metabolisable energy, nitrogen balance and retention, ruminal volatile fatty acid, digestible OM fermented in the rumen, microbial protein synthesis, and serum glucose and aspartate transaminase were increased quadratically (P < 0.05) in 350 g/kg UCH diet. Whereas dry matter and neutral detergent fibre digestibility increased linearly and quadratically (P < 0.05), feed:gain ratio and total N excretion decreased linearly with 350 g/kg UCH diet. Faecal N (linear and quadratic, P < 0.01) and crude protein (CP) digestibility, digestible CP and ruminal pH (linear, P < 0.01) decreased, but urinary N, ruminal total N and ammonia N and serum urea N (linear, P < 0.05) increased with increasing UCH level. Urea-ammoniated cowpea husk is a complete substitute for DBG in goat diet but 350 g/kg UCH optimised the productive performance and metabolic welfare.