Yield and quality components of corn crop residues and utilization of these residues by grazing cattle

Three grazing trials were conducted to evaluate yield, relative plant part composition, quality and utilization (disappearance) of corn crop residues by growing cattle in both dryland and irrigated cornstalk fields. More (P less than .05) total residue was available from irrigated than from dryland cornstalks, but dryland cornstalks had a higher (P less than .05) proportion of leaf plus husk. In Trial 1, 18% of the residue disappeared in 53 d in irrigated fields grazed at 2.47 calves/ha, whereas 32 and 47% disappeared in dryland fields grazed at 1.54 and 2.47 calves/ha, respectively. Leaf plus husk accounted for 69% (Trial 1) and 65 to 72% (Trial 2) of the utilized residue. Utilization rate increased (P less than .05) with stocking rate. All plant parts and leaf plus husk from dryland cornstalks had more CP (P less than .05) and less NDF (P less than .05) than did these plant parts from irrigated fields. In vitro DM disappearance (IVDMD) was decreased (P less than .05) by grazing; this decrease was greater (P less than .05) at higher stocking rates. Husk IVDMD, CP and NDF from 13 corn hybrids differed (P less than .05).