EFFECT OF SUBSTITUTING MAIZE GRAIN WITH COBS TREATED WITH COMBINATIONS OF UREA AND WOOD ASH ON CHEMICAL COMPOSITION AND IN SACCO DEGRADABILITY

Résumé

An experiment was conducted to determine the effect of substituting maize grain with maize cobs treated with 25% urea plus 75% wood ash (WA) on chemical composition and in sacco degradability. Maize grain was substituted with graded levels of 25U75WA in the dietary ingredients and the treatments were: 100M = 100% maize grain, 66M34C = 66% maize grain plus 34% treated maize cobs, 34M66C = 34% maize grain plus 66% treated maize cobs and 100C = 100% treated maize cobs. Samples were analyzed for dry matter (DM), organic matter (OM), ash, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL); they were incubated in sacco for 6, 12, 24, 48 and 72 hrs and their DM degradation kinetics described using the equation y = a + b (1- ect ). Results indicated that as maize grain is substituted with treated maize cobs, NDF, ADF and ADL also increased, however only the neutral detergent soluble (NDS) for treatment 100C was reduced. At 72 hrs of incubation, treatment 34M66C had the highest DM degradation, rapidly soluble fraction ‗a‘ and potential degradability ‗a+b‘. It was concluded that maize cobs treated with combinations of urea and WA could substitute 66% of maize grain in ruminant diets.