EFFECT OF SUBSTITUTING MAIZE GRAIN WITH COBS TREATED WITH A COMBINATION OF UREA AND WOOD ASH ON SHEEP PERFORMANCE AND RUMEN PARAMETERS

Résumé

This study was aimed at determining the effect of substituting maize grain with maize cobs treated with 25% urea plus 75% wood ash (WA) on intake, digestibility, nitrogen utilization, rumen NH3, pH and performance of Tswana breed of sheep. Tswana sheep were fed experimental diet whose 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 in a 4×4 Latin Square Design. Treatment 34M66C had CPI, DMI,OMI and NDFI of 0.1334, 0.9500, 0.8921 and 0.4800 kg/d respectively while the CPD, DMD, OMD and NDFD were 79.57, 68.02, 66.26, and 57.8% respectively. All the treatments had similar rumen NH3 ranging from 23.55 – 24.00 mg/ml while pH were different and ranged from 6.117 – 6.937. Treatment 100M had the lowest pH. Treatment 100M and 34M66C had ADG of 0.1150 and 0.1417 kg/d respectively however treatment 100M had the lowest FCR of 5.217 compared to 7.059 for 34M66C. It was concluded that treatment 34M66C had better nutrient intake, digestibility and performance compared to diet with 100% maize grain and that the substitution could also reduce cost of feed at the same time supplying minerals present in ash to the fed animals.