The effects of supplementation with Gliricidia sepium or Leucaena leucocephala forage on intake, digestion and live-weight gains of Bos taurus X Bos indicus steers offered napier grass.

摘要

Two experiments were carried out to evaluate the effect of incremental levels of Gliricidia sepium and Leucaena leucocephala on forage intake, diet apparent digestibility, microbial nitrogen supply and liveweight changes in cattle. In each experiment, 20 intact and 5 fistulated Bos taurus X Bos indicus steers were used. Napier grass (Pennisetum purpureum) basal diet was offered ad libitum alone or supplemented with gliricidia (experiment 1) or leucaena (experiment 2) 7.5, 15, 22.5, or 30 g DM/kg0.75. In experiment 1, total DM intake increased but not significantly with gliricidia supplementation (5.2, 5.1, 5.2, 5.4, 5.7 kg/day) while intake of napier grass decreased linearly (5.2, 4.7, 4.5, 4.3, 4.2 kg/day, P<0.05). In experiment 2, supplementation with leucaena increased total DM intake linearly without reducing intake of napier grass (5.2, 5.8, 6.2, 6.6, 6.7 kg/day, P<0.001 and 5.2, 5.3, 5.3, 5.3, 5.0 kg/day, respectively). Neither gliricidia nor leucaena supplementation affected apparent digestibility of the diet or in sacco DM degradation characteristics of the forages. Rumen ammonia and liveweight gain were increased linearly (P<0.05) by supplementation from 130 to 215 mg/litre (experiment 1) and 75 to 113 mg/litre (experiment 2), from 306to 478 g/day (experiment 1) and from 538 to 850 g/day (experiment 2), respectively.