THE EFFECT OF VARYING CONCENTRATE: GRASS HAY RATIOS ON FEED INTAKE AND NUTRIENT DIGESTIBILITY BY GROWING WEST AFRICAN FOREST SHEEP

Abstract

Twelve ram lambs of the West African Forest type of between 15.7 and 24.6 kg were divided into four groups of 3 animals each. A group was assigned to one of four diets consisting of the following concentrate: grass hay ratios - 20 : 80 (A), 40 : 60 (B), 60 : 40 (C) and 80 : 20 (D). Feed intake, nutrient digestibilities and efficiency of feed utilization were measured. As the level of concentrate increased, the contents of crude protein ether extract, nitrogen-free extract (NFE) and gross energy of the diets increased, while the crude fibre and ash contents decreased almost linearly. Voluntary feed intake increased with increasing levels of concentrate, with diet C having a significantly higher (P 0.01) Relative Intake (RI) value than the other diets. Both the Nutritive Value Index (NVI) and Digestible Energy (DE) intake values were significantly higher (P. 0.01) in diets C and D than the other diets. Generally, the digestion coefficients for the gross energy, crude protein, crude fibre and nitrogen free extract increased with increasing levels of concentrate, the values being significantly higher (P 0.01) in diets C and D, while diet A showed a significantly lower (P 0.05) dry matter digestion coefficient value when compared with either diets. Although a similar trend was observed in the digestion coefficient for ether extract, the differences were not significant (P 0.05). With the exception of animals on diet C which had the highest daily weight gains, average daily weight gains and efficiency of feed utilization increased with successive substitution of concentrate for grass hay.