Influence of organic acids or fermentable carbohydrates on feeding value of urea treated wheat straw for Nili-Ravi buffalo bulls fed ad libitum diets

Four Nili-Ravi Buffalo bulls were used to study the influence of urea treated wheat straw (UTWS) ensiled with organic acids or fermentable carbohydrates on nutrients digestibility and nitrogen (N) balance. Four diets each having 50% dry matter (DM) from UTWS ensiled with acetic acid (AD), formic acid (FD), acidified molasses (MD) or corn steep liquor (CD) were fed to ruminally cannulated bulls in a 4×4 Latin square design. Higher ruminal ammonia N at 3 and 6 h post prandial was observed with AD and FD diets. However, at 12 h post parandial, ammonia N was higher with MD and CD diets. The digestibility was similar across all treatments. The N balance was higher in bulls fed CD and MD diets than those fed AD and FD diets. Ensiling UTWS with fermentable carbohydrates compared to organic acids increases the N fixation in the matrix of cell wall fiber thus slowing its release at ruminal level that enhanced the N synchronization with carbon skeleton (fiber fermentation) and this consequently minimizes N loss from the rumen. These results indicate that the UTWS ensiled with fermentable carbohydrates is of better feeding value for ruminants than UTWS ensiled with organic acids.