The effect of corn or sorghum dried distillers grains plus solubles on growth performance and carcass characteristics of cross-bred beef steers

Sixty cross-bred steers (Angus ×; n=36 and Charolais ×; n=24) were used in a split-plot design to investigate the effects of feeding corn (Zea mays) or sorghum (Sorghum bicolor) dried distillers grains plus solubles in growing and finishing diets on growth performance and carcass traits. Steers were randomly assigned to one of three dietary treatments used in both feeding periods: a control diet containing soybean meal (n=20; CON), a diet containing 200g/kg (DM basis) corn dried distillers grains+solubles (n=20; CDDGS) and a diet containing 200g/kg (DM basis) sorghum dried distillers grains+solubles (n=20; SDDGS). Steers were fed a corn silage (CS) based grower diet (∼750/kg CS) for 56d and then switched to a high grain finisher diet (150g/kg CS). Feed intakes were measured using Insentec (n=48) and Calan gate (n=12) feeding systems. Animals were weighed every 28d and slaughtered at an estimated backfat of 10mm as estimated by ultrasound. Total trial average daily gain (ADG) was 1.56kg/d±0.04 for CON, 1.54kg/d±0.04 for CDDGS, and 1.51kg/d±0.04 for SDDGS and did not differ (P>0.68) between treatments. Dietary treatment did not affect (P>0.14) dry matter intake (DMI) in the growing phase, although ADG was lower for SDDGS vs. CON (P=0.008) and CDDGS (P=0.02). There was a lower gain:feed in the growing phase for SDDGS vs. CDDGS (P=0.04). In the finishing phase, inclusion of corn or sorghum DDGS did not affect (P>0.41) ADG, DMI or G:F. However, fewer days on feed were required for SDDGS to reach the target backfat for slaughter than CDDGS (P=0.03) and CON (P=0.05). These results indicate that sorghum dried distillers grains plus solubles can be included at 200g/kg inclusion level, similar to corn distillers grains plus solubles, in grower and finisher diets, without negatively influencing overall growth or carcass traits, although feeding SDDGS may result in reduced performance when corn silage based diets are fed and results in earlier fattening at a lighter body weight.