Effects of grind size when alkaline treating corn residue and impact of ratio of alkaline-treated residue and distillers grains on performance of finishing cattle

Effects of processing treated corn stover and distillers' grains on performance and total tract digestion of finishing cattle

Two studies evaluated effects of replacing corn with a pellet containing alkaline treated corn stover, dried distillers' grains plus solubles (DDGS), and distillers' solubles on total tract digestion and performance of finishing cattle. Experiment 1 used 4 ruminally fistulated steers in a 4 × 6 Latin rectangle to evaluate total tract digestion. Treatments consisted of a control (CON) containing 50.3% dry-rolled corn (DRC), 40% modified distillers' grains plus solubles (MDGS), and 5% untreated corn stover. The next 2 treatments replaced 25% DRC (DM basis) with either a CaO-treated stover pellet (STOVPEL) or a pellet consisting of 64% CaO-treated corn stover, 18% DDGS, and 18% corn distillers' solubles (COMBPEL). The last treatment replaced 25% DRC with a mixture of feeds: 10% treated stover pellet, 10% DDGS, and 5% distillers' solubles (COMB). Experiment 2 used 336 crossbred steer calves (301 ± 25 kg initial BW) in a 2 × 3 + 1 factorial to evaluate effects of replacing corn with a pellet containing 64% CaO-treated corn stover, 18% DDGS, and 18% corn distillers' solubles on finishing performance. Factors included level of MDGS (20 or 40%) and pellet inclusion (10, 20, or 30%). The CON diet contained a 50:50 blend of DRC and high-moisture corn and 40% MDGS. All diets contained 5% wheat straw and 4% dry meal supplement. In Exp. 1, no differences ( ≥ 0.50) were observed between the CON, STOVPEL, COMB, or COMBPEL treatments for DM (76.5, 75.4, 72.5, and 78.0%, respectively; SEM 2.5) or OM (79.1, 79.7, 75.7, and 80.5%, respectively; SEM 2.4) digestibility. In Exp. 2, a linear increase ( = 0.03) in DMI was observed as pellet inclusion increased from 0% in the CON (10.6 kg/d [SE 0.13]) to 30% (11.0 kg/d [SE 0.13]) in treatments containing 40% MDGS. A quadratic response ( = 0.03) in DMI was observed as pellet inclusion increased in diets containing 20% MDGS due to greater DMI of the 20% pellet treatment. A linear decrease ( = 0.03) in G:F was observed as the level of pellet inclusion increased from 0 (0.182 [SE 0.02]) to 30% (0.175 [SE 0.02]) in diets containing 40% MDGS. In diets containing 20% MDGS, no differences ( ≥ 0.22) in G:F were observed as pellet inclusion increased from 10 to 30%. In conclusion, replacing up to 20% of corn (DM basis) in diets containing 20% MDGS had minimal impact on performance. Conversely, up to 30% of corn could be replaced in diets containing 40% MDGS with little impact on performance.