Using sorghum dry distillers’ grains plus solubles in sorghum-based finishing diets: feed utilization, cattle performance and carcass traits

Abstract

The present study evaluated the effect of increasing levels of inclusion of sorghum dry distillers’ grains plus soluble in a sorghum-grain-based diet on the performance, apparent dry matter digestibility, ingestive behavior, and carcass traits of feedlot finishing steers. Thirty-two Hereford steers (331.2 ± 33.5 kg) were randomly allocated to four total mixed rations differing in SDDGS concentrations, 0, 150, 300, or 450 g/kg. The SDDGS replaced sorghum grain and sunflower meal in the control diet (Setaria italica hay 200 g/kg, ground sorghum 650 g/kg, sunflower meal 100 g/kg, and 50 g/kg premix) balancing for at least 125 g/kg of crude protein in the diet. Animals were fed in individual pens at 2.8 kg DM/ 100 kg body weight delivered in three meals over 12 weeks. Steers were all slaughtered on the same date. The experiment was analyzed according to a randomized plot design with repeated measures, and linear and quadratic effects associated with the SDDGS level were tested. Increasing SDDGS did not affect BW gain (1.52 kg/d, SE 0.06 kg/d), carcass weight (240.0 kg SE 5.3), carcass yield (542 g/kg SE 4.7), or ribeye area (49.1 cm2 SE 2.6). However, a negative linear tendency was observed for subcutaneous backfat (P < 0.10). No differences were observed in digestible DM or digestible energy intake (P> 0.10), nor in the gain-to-feed ratio (0.142, SE 0.01). Including SDDGS reduced steers’ intake activity (P < 0.01), but linearly increased the intake rate during the first meal (g/min, P < 0.01), without affecting diet NEg (P> 0.10). Our data suggest that for sorghum grain-based diets it is feasible including SDDGS in up to 450 g/kg without affecting animal performance or carcass value.