Effects of urea and saccharose on intake and digestion of a Digitaria decumbens hay by black belly sheep

Effects of incorporation of urea and saccharose in diets, on intake and dig estion by sheep of a 35-day-old pangola (Digitaria decumbens) hay, have bee n studied according to a 4 X 4 Latin-square design. Sixteen rams were given four diets: hay (C); hay plus urea (U; 23 g/kg hay); hay plus saccharose ( S, 60 g/kg hay), hay plus urea and saccharose (SU). Acid-detergent fibre an d crude protein (CP) content of the roughage were 395 and 78 g/kg dry matte r (DM) respectively Intake of hay (g DM per kg live weight(0.75)), suppleme nted with urea and sugar (42.9), was lower (P < 0.05) than with other diets (47.2, s.e. 1.6). The organic matter (OM) total tract and ruminal digestib ility of the diet C, S, LS and SU were 0.622, 0.590, 0.625 and 0.587 (s.e. 0.007); 0.361, 0.380, 0.378 and 0.345 (s.e. 0.015) respectively. Effective degradation and nylon bag kinetics of DM degradation were higher with U and S compared with S or C. Few differences were observed between diets for ru minal concentration of volatile fatty acids. The ruminal ammonia concentrat ions were higher (P < 0.05) for the diets with urea than without urea (78 v . 215 mg/l). The efficiencies of the microbial synthesis (g nitrogen per kg OM fermented in the rumen) were, 23.6, 22.4, 24.9 and 29.3 (s.e, 1.7)for t he diets C, U, S and SU respectively. Even though additional urea increased nitrogen availability for ruminal bacteria, urea supplementation did not a ffect significantly intake or digestion of the pangola hay of medium CP con tent used in this experiment.