Effect of high-oil corn on growth performance, diet digestibility, and energy content of finishing diets fed to beef cattle

Sixty crossbred beef steers (initial BW = 412 kg) were used in a 83-d finis hing study to deter mine the effect of feeding dry rolled high-oil corn on performance and total-tract digestibility of finishing diets. Steers were a llotted by weight to the following dietary treatments: 1) control corn (C; 82% normal corn, 12% triticale silage), 2) high-oil corn (HO; 82% high-oil corn, 12% silage), and 3) high-oil corn formulated to be isocaloric to C (I SO; 74% high-oil corn, 20% silage). Total lipid content was 4.9% (DM basis) for normal corn and 7.0% for high-oil corn. Steers were individually fed u sing electronic gates. Quantity of feed offered and refused was recorded da ily. Fecal samples were collected on d 63 to 66 of the trial to determine d igestibility. Chromic oxide was fed as an indigestible marker for 7 d befor e fecal collection began. Planned contrasts of HO vs C and ISO vs C were us ed to assess treatment differences. Dry matter intake was greater for steer s fed C vs HO (P < 0.01) or C vs ISO (P < 0.01), but daily gain and feed ef ficiency were not affected (P > 0.05) by treatments. Digestibility of DM, O M, starch, and GE was greater (P < 0.05) for the HO diet than the C diet, b ut lipid digestibility did not differ among treatments (P > 0.05). The comb ined effect of greater GE content and digestibility resulted in greater (P < 0.01) DE content for the HO than for the C diet. Calculated DE of the cor n was 8.3% greater (3.74 Mcal/kg; P < 0.01) for the HO diet and 6.5% greate r (3.67 Mcal/kg; P < 0.01) for the ISO diet than the corn in the C diet (3. 25 Mcal/kg). Dry matter and GE digestibility did not differ (P > 0.05) betw een the C and ISO diets. Steers consuming ISO had greater (P < 0.05) starch digestibility than steers fed the C diet. Although HO had higher DE, DE in take was similar (P > 0.05) for HO and C due to lower DMI for HO. These res ults indicate that available energy is greater from high-oil corn than from typical corn, but depressed voluntary feed intake prevented performance im provements and resulted in equal energy intakes between high-oil corn and t ypical corn diets.