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Effects of processing of treated corn stover and distillers grains on intake and digestibility of feedlot diets
Four ruminally fistulated steers were utilized in a 4 x 6 Latin rectangle design to evaluate the effects of replacing dry-rolled corn (DRC) with a pelleted feed containing treated corn stover and distillers grains (DGS). The control (CON) treatment contained 50.3% DRC, 40% DGS, 5% stalks, and 1.7% limestone. The first treatment (TRT 1) consisted of 27% DRC, 40% DGS, 25% treated stover pellet, and 5% stalks. The second treatment (TRT 2) contained 25.9% DRC, 40% DGS, 10% treated stover pellet, 10% DGS, 5% solubles, 5% stalks, and1.1% limestone. Treatment 3 (TRT 3) contained 27% DRC, 40% DGS, 25% treated corn stover and distillers pellet, and 5% stalks. The diet for TRT 2 was formulated to be of similar energy value as the treated stover and distillers pellet in TRT 3. Pellets used in TRT 1 contained corn stover that had been processed differently compared to the pellets fed in TRT 3. All treatments contained 3% supplement. Data were analyzed using the mixed procedures of SAS. There were no (P ≥ 0.15) differences between the CON, TRT 1, TRT 2, or TRT 3 were observed for DM (10.10, 7.45, 8.49, and 8.52 kg/d, respectively), OM (8.07 ± 2.15 kg/d), or NDF (2.71 ± 0.65 kg/d) intakes. Correspondingly, no differences (P ≥ 0.50) were observed between the CON, TRT 1, TRT 2, or TRT 3 for DM (75.41± 5.21%), OM (78.59, 78.81, 77.40, and 79.98 %, respectively) or NDF (62.35, 72.63, 68.35, and 68.11%, respectively) digestibilities. Proportions (mMol/100 mMol) of acetate (54.75 ± 0.72), propionate (26.71 ± 1.10), and butyrate (12.05 ± 0.72) were not different between the four treatments (P > 0.50). There was a difference (P < 0.05) in maximum ruminal pH recorded with the treatments having a maximum pH of 6.30 (CON), 6.66 (TRT 1), 6.29 (TRT 2), and 5.96 (TRT 3). There was a tendency (P = 0.09) for differences in average ruminal pH, with treatment differences following the same trend as seen in maximum pH. Differences in maximum pH were attributed to varying pH of the two pellet types. It was concluded that the DRC could be replaced with a pelleted stover and distillers in the finishing diet without altering total tract digestion.
Keywords:
cattle, pellet, treated stover