Influence of fibrolytic enzymes on ruminal disappearance and fermentation in steers fed diets with short and long particle length of forage

The effects of an exogenous fibrolytic enzyme mixture on in sacco ruminal disappearance and fermentation of growing (380 kg body weight) and finishing (440 kg body weight) steers fed with diets to short (10 mm) and long (50 mm) particle length (PL) were evaluated. Four Holstein steers fitted with ruminal cannulas were randomly assigned to: (1) diet with short PL forage; (2) diet with short PL forage + enzyme; (3) diet with long PL forage; (4) diet with long PL forage + enzyme. Fibrolytic enzymes did not affect dry matter intake. In growing steers, potentially disappearance fraction and total disappearance of DM, starch, NDF and ADF were increased by enzymes. In finishing steers, enzymes increased potentially disappearance fractions and total disappearance of DM, starch, NDF and ADF. In both growing and finishing steers, enzymes increased ruminal ammonia concentrations. Enzymes increased ruminal disappearance of diets for steers, but it had scarce effects on ruminal fermentation and intake.