Effect of organic acids or fermentable carbohydrates on digestibility and nitrogen utilisation of urea-treated wheat straw in buffalo bulls

Influence of urea treated wheat straw (UTWS) ensiled with organic acids and fermentable carbohydrates on ruminal parameters, digestion kinetics, digestibility, and nitrogen (N) balance was studied in Nili-Ravi buffalo bulls fed restricted diets. Four diets having 50% UTWS ensiled with acetic acid (AD), formic acid (FD), acidified molasses (MD), and corn steep liquor (CD) were fed to ruminally cannulated bulls in a 4 × 4 Latin square design. Higher ruminal ammonia N at 3 h post feeding was observed with AD and FD diets; however, at 9 and 12 h post feeding it was higher with MD and CD diets. Ruminal total volatile fatty acids and acetate concentrations were significantly higher with MD and CD diets than AD and FD diets. The ruminal degradability, rate of disappearance, and lag time of dry matter (DM) and neutral detergent fibre (NDF) were statistically higher with MD and CD diets than AD and FD diets. Total bacterial, viable, and cellulolytic ruminal counts were significantly higher in bulls fed CD and MD diets than AD and CD diets. The digestibility of DM, organic matter, NDF, and acid detergent fibre was significantly higher in bulls fed CD and MD diets than AD and FD diets. The N retained out of N intake was higher in bulls fed CD and MD diets than those fed AD and FD diets. This study indicated that the UTWS ensiled with fermentable carbohydrates is of better feeding value for ruminants than UTWS ensiled with organic acids.