Effects of alkaline treatment and pelleting of crop residues on performance of growing calves1

Two experiments used 2 × 2 factorial arrangements of treatments to determine effects of pelleting and alkaline treatment of residues on performance of growing steers. In Exp. 1, 480 steers (initial BW = 312 kg; SD = 16) were used to evaluate pelleting the diet and alkaline treatment of corn residue (5% CaO + H2O or 6.6% calcium hydroxide vs. none). In Exp. 2, 460 steers (initial BW = 331 kg; SD = 20) were used to evaluate alkaline treatment (5% CaO + H2O vs. none) and residue type (corn residue vs. wheat straw). In Exp. 1, no interaction between alkaline treatment and pelleting was observed (P ≥ 0.18). Pelleting increased DMI and ADG (P < 0.01) but reduced G:F (P < 0.01). Alkaline treatment increased DMI, ADG (P < 0.01), and G:F (P < 0.05). In Exp. 2, an interaction between crop residue and alkaline treatment was observed for ending BW and ADG (P < 0.01). Steers fed treated corn residue had 9.2% greater ADG and 1.1% greater ending BW when compared with steers fed untreated corn residue, whereas steers fed treated wheat straw diets had increases of 25.7% for ADG and 3.4% for ending BW compared with steers fed untreated wheat straw. Wheat straw increased DMI by 8% (P < 0.01) and improved G:F by 5% (P = 0.05) when compared with corn residue diets. Alkaline treatment improved G:F by 6.4% (P = 0.03) and increased DMI by 9.6% (P < 0.01). Overall, pelleting increased DMI and ADG but reduced G:F, whereas alkaline treatment increased ADG and G:F.