Impact of Feeding Distillers Grains with or without Oil Removal As Well As Oil Replenished on Nutrient Digestibility By Finishing Cattle

A digestion experiment was conducted to determine the effect of adding corn oil to the diet on total tract digestibility of finishing cattle. The 70-d digestion trial was designed as a 5 × 4 unbalanced Latin rectangle with 4 diets, 5 ruminally cannulated steers, and 5 periods. The four treatments consisted of a corn control diet (CON), 40% deoiled MDGS (DOMDGS), 38% deoiled MDGS plus 2% corn oil (MDGS+Oil), and 40% full fat MDGS (FFMDGS). The DOMDGS product contained 8.9% fat while the full fat MDGS product was 11.6% fat. Dietary fat was 4.2% for CON, 6.0% for DOMDGS, 7.9% for MDGS+Oil, and 7.1% for FFMDGS. All MDGS and corn oil were sourced from the same plant. Each period was 14 d which consisted of 10 d of adaptation followed by 4 d of fecal collection, 4 times per day. Titanium dioxide was dosed intraruminally twice daily throughout the entire experiment as a marker to determine fecal output. Intake of DM, OM, and energy, as well as total tract fat digestibility, and DE (Mcal / d) were not impacted by dietary treatment (P > 0.46). Cattle fed all three treatments containing MDGS had similar (P > 0.10) DM excreted, OM excreted, NDF intake, NDF excreted, fat excreted, and fecal energy excretion, but greater than steers fed CON (P < 0.03). Fat intake was greatest and similar for MDGS+Oil and FFMDGS (P = 0.47), intermediate DOMDGS (P = 0.08), while fat intake was least for CON (P < 0.01). Total tract OM digestibility was greatest for cattle fed CON (83.6%; P < 0.01), while DOMDGS and FFMDGS were intermediate and similar (79.1% and 78.1% for DOMDGS and FFMDGS, respectively; P > 0.39), and MDGS+Oil was lowest (75.6%) but similar to FFMDGS (P = 0.10). Total tract digestibility of NDF was greater for FFMDGS compared to CON and MDGS+Oil (P < 0.04) but not compared to DOMDGS. Feeding FFMDGS resulted in the greatest DE (Mcal/kg; P < 0.04), DOMDGS was similar to both FFMDGS (P = 0.40) and CON (P = 0.17). However, feeding CON resulted in a lower DE compared to FFMDGS (P = 0.04). The MDGS+Oil diet had the lowest DE (P < 0.01). When corn oil was added back to MDGS there was a negative impact on digestibility of OM and NDF, as well as lower DE (Mcal/kg) compared to DOMDGS or FFMDGS.