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Use of treated corn residues in growing diets
A growing study was utilized to evaluate the effects of pelleting or grinding corn residue and alkaline treatment versus none. This growing research was completed at the Agricultural Research and Development Center (ARDC) near Mead, NE. The trial consisted of 480 backgrounded crossbred steers (BW = 312±8 kg) grown for 80 days. Steers were sorted into four weight blocks, stratified by BW within block, and assigned randomly to pens. Pens were assigned randomly to one of four treatments, with seven pens per treatment and 16 or 24 steers per pen balanced by block. Pen served as the experimental unit. Treatments were arranged in a 2 x 2 factorial with corn residue processing (grinding vs pelleting) and chemical treatment (none vs alkaline) as the factors. Pellets were processed and provided by Iowa Agricultural Bio Fiber out of Harlan, Iowa. All diets contained 60% corn residue, 36% distillers grains, and 4% supplement (DM basis). Both treated and untreated corn residues were ground (7.62-cm screen) and chemically treated at ARDC. All corn residue (ground and pelleted) originated from the same source. No residue form x treatment interactions were observed for this trial. Ending BW, DMI and ADG were increased (P < 0.01) due to pelleting when compared to grinding. However, the relative increase in ADG (8% vs. 10% for untreated and treated diets respectively; P < 0.01) was smaller than the increase in DMI (21% vs. 19% for untreated and treated diets; P < 0.01) resulting in poorer G:F for the pelleted diets (P < 0.01). Alkaline treatment increased ending BW, DMI, and ADG (P < 0.01) and improved G:F (P < 0.05). The improvement in feed conversion due to chemical treatment was numerically less in ground diets than in pelleted diets (1% vs. 6% for ground and pelleted diets respectively; P < 0.01). In growing diets, the expense of chemical treatment may increase the cost per unit of energy of the corn residue compared to untreated corn residue because of the small improvement in G:F. However, using a pelleted ration for growing calves could be a feasible option to achieve additional gain if the diet is favorably priced.
Keywords: corn residue, growing, pellet