Effect of dried distillers grains with solubles or corn in growing cattle diets, followed by a corn-based finishing diet, on performance of feedlot cattle

The experiment was conducted to evaluate growth performance of cattle fed a dried distillers grains with solubles (DDGS)-based diet during the growing phase followed by a corn-based finishing diet in comparison with cattle fed a corn-based diet throughout the entire feeding period. Seventy Angus×Simmental cattle (42 steers and 28 heifers; 351±6.8kg average initial BW) were blocked by BW and sex and allotted to 2 dietary treatments in a randomized complete block design. Treatments were: (1) corn-based diet fed for 126 days (control), and (2) 60% DDGS diet fed for 70 days followed by the corn-based control diet fed until day 126 (DDGS/Corn treatment). Average daily gain, DMI, G:F, and dietary NE_m and NE_g were determined from day 0 to 70 (period 1; growing phase), day 71 to 126 (period 2; finishing phase), and day 0 to 126 (overall). Statistical analyses were conducted using the MIXED procedure of SAS. Average daily gain and G:F were greater (P≤0.01) for the control than for the DDGS/Corn treatment in period 1, but greater (P<0.01) for the DDGS/Corn treatment in period 2 when compared to the control treatment. However, there were no differences (P≥0.44) in ADG and G:F between treatments over the entire feeding period. Animals from the control treatment had greater (P≤0.01) DMI in period 1 and overall. Calculated dietary NE_m and NE_g were greater (P<0.01) for the DDGS/Corn treatment when compared to the control treatment only in period 2. However, the observed-to-expected ratios of NE_m and NE_g were greater (P≤0.01) for the DDGS/Corn group in all periods. Moreover, total corn intake was decreased (P<0.01) for the DDGS/Corn group in period 1 and overall, although no differences (P=0.50) were observed between treatments in period 2. In conclusion, feeding DDGS-based diets to growing cattle negatively affects performance during the initial feedlot period, but when cattle are switched to a corn-based diet in the finishing phase, those negative effects are overcome due to compensatory growth, and overall performance is similar to that of cattle fed corn for the entire feeding period (126 days). Thus, increasing DDGS in the diets of growing cattle and then switching to a corn-based finishing diet is a nutritional strategy that can be used to decrease feed costs and reduce beef producers' reliance on corn grain when corn prices are elevated.