Ruminal fermentation of Nellore steers fed crude glycerine replacing starch vs. fibre-based energy ingredient in low or high concentrate diets

ABSTRACT. Twelve ruminally cannulated steers (401.0 ± 41.5 kg) and 24 mo were used in a replicated arrangement truncated Latin Square with six animals in six treatments and four periods to evaluate the effect of crude glycerine (CG; 80.3% of glycerol) with starch or fiber-based energy ingredients in the concentrate on DMI, DM (DMD) and NDF digestibility (NDFD) and ruminal parameters. Experimental periods were 19 days (14 days for adaptation and 5 days to sampling). Diets were: CO - without CG and corn as ingredient of concentrate; CGC - inclusion of CG (10% of DM) with corn in the concentrate; and CGSH - inclusion of CG (10% of DM) with soybean hulls (SH) in the concentrate. All three diets were offered at low (LC) or high (HC) concentrate level, CL (40 or 60%). Animals fed LC or HC diets had similar DMI, DMD and NDFD. Animals fed diets with CG associated with corn or SH had higher propionate concentrations and lower A:P ratio. Diets with HC increase the propionate but do not affect the NDFD. CG (10% of DM) can be used to replace corn or SH in diets with 40 or 60% of concentrate, without affect NDFD.