Effects of feeding calcium oxide on growth performance, carcass characteristics, and ruminal metabolism of cattle

Three experiments tested the effects of feeding CaO as part of the TMR or as CaO-treated corn stover (CS) on growth performance, carcass characteristics, and ruminal metabolism of cattle. In Exp. 1, steers (n = 162) were fed 1 of 3 diets containing 20% CS and 40% modified wet distillers grains with solubles: untreated CS (UCS), treated CS with 5% CaO (DM basis; TCS), and dietary inclusion of 1% CaO (DM basis; DC). Feeding DC or TCS decreased (P < 0.05) DMI, final BW, HCW, and back fat compared with feeding UCS. Feeding TCS decreased (P < 0.05) ADG compared with feeding UCS. In Exp. 2, heifers (n = 138) were fed 1 of 3 diets: UCS, TCS, and 40% corn silage (DM basis; SIL). Feeding TCS decreased (P = 0.05) DMI, and final BW, and back fat compared with feeding UCS and SIL. Heifers fed UCS had similar (P = 0.05) ADG, DMI, and marbling score as heifers fed SIL; however, final BW and G:F were decreased (P = 0.05). In Exp. 3, steers (n = 5) were fed in a 5 × 5 Latin square; diets were UCS, TCS, DC, SIL, and a control of 50% cracked corn. Feeding TCS tended to decrease (P = 0.06) ruminal pH when compared with UCS. Steers fed UCS had the least (P = 0.05) DM digestibility and steers fed the control had the greatest. Treating CS with CaO effectively increased digestibility; however, it did not improve cattle performance. Feeding cattle untreated, ensiled CS resulted in ADG and G:F comparable to feeding corn silage.