Effects of dry-rolled or high-moisture corn with twenty-five or forty-five percent wet distillers' grains with solubles on energy metabolism, nutrient digestibility, and macromineral balance in finishing beef steers

The effects of feeding a dry-rolled corn–based diet (DRCB) or a combination of a high-moisture corn–based diet (HMCB) with dry-rolled corn (DRC; 2:1 ratio of high-moisture corn [HMC] and DRC) with 25 and 45% wet distillers’ grains with solubles (WDGS) on energy metabolism and nutrient and mineral balance were evaluated in 8 finishing steers using a replicated Latin square design. The model included the fixed effects of dietary treatment, the WDGS × diet type interaction, and period and the random effects of square and steer within square were also included. Treatments consisted of a DRCB with 25% WDGS, a DRCB with 45% WDGS, a combination of HMCB and DRC with 25% WDGS, and a combination of HMCB and DRC with 45% WDGS. Cattle consuming DRCB consumed a greater amount of DM (P < 0.01) and GE intake was also greater when feeding DRCB with 25% WDGS than when feeding DRCB with 45% WDGS (P< 0.01). As a proportion of GE intake, cattle consuming HMCB had a greater fecal energy loss (P = 0.01). Digestible energy loss as a proportion of GE intake was greater when cattle were fed DRCB than when cattle were fed HMCB (P = 0.01) and when WDGS was included at 45% of DM (P = 0.05). As a proportion of GE intake, cattle consuming DRCB and 25% WDGS respired a greater amount of methane (Mcal) than cattle consuming 45% WDGS. As a proportion of GE intake, ME was greater in DRCB than in HMCB (P = 0.01). Within HMCB, 45% WDGS had more megacalories of retained energy than 25% WDGS. Nitrogen excretion (g) was greater in the urine (P < 0.01) and feces (P < 0.05) when 45% WDGS was included. As a proportion of N intake, total N retained was greater when a greater amount of WDGS was included in the diet (P = 0.05). Digestibility was greater in DRCB than in HMCB (P = 0.02). Starch intake, excretion, and digestibility as a proportion of intake were greater in DRCB than in HMCB (P < 0.01) and when WDGS was included at 25% than when WDGS was included at 45% of the diet (P < 0.01). Intake of ether extract was greater in HMCB when 45% WDGS was included (P < 0.01), and fecal excretion was greater in diets including 25% WDGS than in diets including 45% WDGS (P = 0.02). Sulfur intake was greater as the inclusion of WDGS increased from 25 to 45% (P < 0.01). We interpret that if the basal concentrate portion of the diet is based on HMC, adding an increased amount of WDGS can improve retained energy, and within DRCB, more energy is retained as fat and carbohydrate when cattle were fed 25% WDGS.