Effect of supplementation with tree leaves on intake and digestibility of hybrid napier (NB-21) grass in Nellore Brown sheep

Abstract

Effect of supplementation of leaves from fodder trees such as Leucaena leucocephala, Sesbania grandiflora and Gliricidia maculata on dry matter (DM) intake and nutrient digestibility of hybrid napier grass (1.14% nitrogen) based rations was evaluated in two experiments with native Nellore Brown sheep. In Experiment 1, sheep received four dietary treatments, hybrid napier grass (NB-21) ad libitum (control) or grass plus 600 g day −1 of one of the three fodder tree leaves to have a grass:tree leaf ratio of 60:40 on DM basis. Supplementation with leucaena, sesbania and gliricidia decreased the total DM intake (g DM day −1) of the ration from 414 (control) to 392, 351 and 387, respectively. However, the effect of supplementation on DM intake was not significant ( P > 0.05). Crude protein digestibility was significantly ( P < 0.05) improved in all supplementation treatments. Sheep in all the four treatments were in positive N, Ca and P balance. Rumen degradability of fodder tree leaves was studied using the nylon bag technique in association with the fermentation characteristics of sheep fed rations containing different tree leaves in Experiment 2. Sesbania leaf was highly degradable in the rumen with 73% of the DM disappearing after 24 h incubation. In contrast, leucaena and gliricidia leaves exhibited a low degradability of 64.5% and 72.7%, respectively, after 48 h in the rumen. Effective degradation of DM was highest with sesbania (64.2%), intermediate with gliricidia (55.9%) and least with leucaena (41.6%). The relative ability of the fodder tree leaves to improve the total tract digestion of NB-21 grass is discussed, particularly in relation to rumen degradability of DM.