In vitro gas production in rumen fluid of buffalo as affected by urea‐calcium mixture in high‐quality feed block

This study aimed to determine the effect of urea‐calcium sulphate mixture ( U ‐cas) levels in high‐quality feed block ( HQFB ) on ruminal digestibility, fermentation and gas kinetics in rumen fluid of swamp buffalo by using in vitro techniques. The treatments were seven levels of U ‐cas incorporated in HQFB at 0, 3, 6, 9, 12, 15 and 18% and the experimental design was a completely randomized design. Gas production rate constants for the insoluble fraction, potential extent of gas and cumulative gas were linearly increased with increasing levels of U ‐cas in HQFB . The in vitro dry matter digestibility, in vitro organic matter digestibility, true digestibility and microbial mass were altered by treatments and were greatest at 18% U ‐cas supplementation. Concentrations of propionate were linearly increased with increasing levels of U ‐cas and was highest with U ‐cas supplementation at 18%. The NH 3 – N concentration was highest when urea was added in the HQFB while NH 3 – N concentration tended to be reduced with increasing level of U ‐cas. The findings suggest supplementation of 18% U ‐cas in HQFB improves kinetics of gas production, rumen fermentation, digestibility and microbial mass as well as controlling the rate of N degradation in the rumen of swamp buffalo.