The experiment was carried out with the objective to evaluate the ruminal parameters, volatile fatty acids production and in situ degradability of Santa Gertrudis young bulls, canulated in the rumen, fed diets with palisadegrass hay and concentrates. A 4 x 4 latin square design was used, in which the treatments were composed by the concentrates, adjusted for daily body weight gain (BWG) of 0.5 and 1 kg/animal and potential microbial fermentation (y) of 9.5 and 11 g microbial crude protein/MJ fermentable metabolizable energy. No differences were observed for pH, molar concentration of acetic and butyric acids, molar proportion of acetic, propionic and butyric acids and acetic:propionic ratio. There were differences between diets for the different potential microbial fermentations for ammonia level, 14.67 and 20.83 mg/100 mL for low and high, respectively, and for molar concentration of propionic acid, differed between the different potentials for weight gain, 7.62 and 8.94 mM, respectively, for low and high weight gain. There were no differences among diets for the degradability fractions of palisedagrass hay and soybean grain. There were difference in parameter "b" and effective degradability at 5%/hour of CP for the potential BWG of corn grain. There was significant interaction between potential BWG and potential microbial fermentation for some parameters of DM and CP of soybean meal, the same was observed for cottonseed meal. The observe differences did not justify the the concentrate balance for the different evaluated production potential.
corn grain; cottonseed meal; potential of bodyweight gain; potential of microbial fermentation; soybean grain; soybean meal
