Effect of Type and Level of Foliage Supplementation on Voluntary Intake and Digestibility of Rice Straw in Sheep

In-vivo balance and nylon bag studies were conducted with rumen fistulated sheep to investigate the effect of type, i.e. Leucaena (L), Gliricidia (G) and Tithonia (T), and level (1, ~15; 2, ${\sim}30g\;DM/kg^{0.75}$) of foliage supplementation on voluntary intake and digestibility of rice straw. Inclusion of these leafy supplements in the diet significantly increase total feed intake. On a metabolic weight basis ($kg^{0.75}$), voluntary intake of digestible DM increased from 23.8 (control straw diet) till 27.7 (L1), 28.4(G1) and 33.1(T1) for the lover level, and till 34.8(L2), 35.9(G2) and 39.6(T2) $g/kg^{0.75}$ for the higher level of supplementation, respectively. Rumen pH was stable, on average 6.75 (control values) and ranging from 6.67 till 6.91 with the supplements. Rumen ammonia increased from 4.9 till 6.7 to 11.8 mmol/l with the supplements. The highest increase was obtained with G and the lover with L and T. The nylon bag studies showed that contrary to the rate of degradation of the supplements themselves, supplementation did not affect the in-sacco rate of straw dry matter degradation ($k_d$; range 1.87-2.08 %/h). At the higher supplement level, for L, G and T, $k_d$ values were 3.36, 8.16 and 8.58 %/h, respectively.