Energy value of dry maize gluten feed in starter, growing or finishing steer diets

Three experiments were conducted to determine the metabolizable energy (ME) concentration of dry maize gluten feed (DMGF) in starter (experiment 1), growing (experiment 2) or finishing (experiment 3) diets for steers. Seventy-two weanling Holstein-Friesian steer calves (initially 52 kg live weight); 32 Aberdeen Angus and 24 Shorthorn steer calves (initially 250 kg live weight) and 32 Aberdeen Angus, 24 Shorthorn and 68 crossbred steers (initially 367 kg live weight) were used in experiments 1, 2 and 3, respectively. In experiment 1, calves were given one of three total mixed rations in which energy and protein ingredients on a dry matter (DM) basis were (g/kg): (1) 590 ground maize grain (MG), 260 rolled oats (RO) and 150 soya-bean meal (SBM); (2) 210 DMGF, 400 MG, 260 RO and 130 SBM; or (3) 440 DMGF, 210 MG, 250 RO and 100 SBM. Daily live-weight gains (LWG) and food-to-gain (F/G) ratios were similar across dietary treatments (P > 0·05). Calves given the diet containing 440 g DMGF per kg had higher DM intakes (DMI) than those given no DMGF (P < 0·05). ME concentration of the diet without DMGF was greater than ME concentrations of diets containing DMGF (P < 0·05). In experiment 2, calves were given one of four diets containing, on a DM basis (g/kg): (1) 800 maize silage (MS) and 200 MG; (2) 800 MS and 200 DMGF; (3) 500 MS and 500 DMGF; or (4) 200 MS and 800 DMGF. LWG and DMI of calves given 500 or 800 g DMGF per kg diets were higher than those of calves given 0 or 200 g DMGF per kg diets (P < 0·05). F/G ratios tended to increase and dietary ME concentrations tended to decrease with increasing content of DMGF in diets. In experiment 3, steers were given one of four diets, which on a DM basis were (g/kg): (1) 850 MG and 150 MS; (2) 300 DMGF, 150 MS and 550 MG; (3) 500 DMGF and 500 MG; or (4) 750 DMGF and 250 MG. LWG was not altered when DMGF replaced MG only or MG and MS (diet 2 v. 1 or diets 3 and 4 v. 1, respectively (P > 0·05)) in the diet. Steers given the 300 or 750 g DMGF per kg diets had higher DMI and lower F/G ratios than those fed diets without DMGF (P < 0·05). ME concentration of the diet without DMGF was greater (P < 0·05) than the ME concentration of 300 or 750 g DMGF per kg diets. ME concentration of DMGF, calculated by regression, was proportionately about 0·9 of the value of MG in all experiments and averaged 11·46 MJ/kg DM.