Growing performance and digestion parameters in steers fed increasing concentrations of de-oiled corn condensed distillers solubles in forage-based diets

The objective of these experiments was to evaluate the impacts of increasing dietary de-oiled con-densed distillers solubles (CDS) on cattle performance and nutrient digestibility. In Exp. 1, 68 crossbred steers (initial BW = 366 kg; SD = 30 kg) were blocked by weight in a generalized randomized complete block designed study. Steers were individually fed CDS at 0%, 10%, 20%, 30%, or 40% of the diet displacing dry-rolled corn in a forage-based diet for 96 d. In Exp. 2, 6 rumi-nally cannulated steers (BW = 404 kg; SD = 34 kg) were utilized in a 6 × 6 Latin square design to determine the effects of CDS in a forage-based diet on diet digestibility and rumen fermentation parameters. Steers were fed CDS at 0%, 10%, 20%, 30%, or 40% of the diet displacing dry-rolled corn (DRC), and an all-grass hay control. Ending BW and ADG were not different due to inclusion level of de-oiled CDS. There was a quadratic effect on DMI as level of the de-oiled CDS increased, with the greatest DMI occurring at 20% CDS. A quadratic response for G:F with the poorest feed con-version at the 20% CDS inclusion was observed. In Exp. 2, DM, OM, and NDF intake linearly decreased as CDS in-clusion increased. Dry matter and OM intake were greater for the 0% CDS diet than the control diet. Gross energy intake was not different with increasing concentrations of CDS. Molar concentration of acetate linearly decreased, whereas propionate and butyrate linearly increased with increasing concentrations of CDS. Replacing DRC with de-oiled CDS in a forage-based diet did not improve steer performance. The results of Exp. 2 suggest that energy intake is not different when de-oiled CDS replaces DRC, and based on rumen parameters, CDS reacts similarly to DRC in forage-based diets in that acetate decreased and propionate increased, resulting in decreasing A:P.