Enhancing the feeding value of corn residues to improve beef cattle production

Abstract Text: Objectives were to test the feeding value of corn plant residue, harvested at 2 maturities, and the effects of silage additive, propionic acid or lactobacillus, on in situ fiber disappearance, and growth performance and carcass characteristics of growing feedlot cattle. In Exp. 1, steers were allotted to 1 of 4 treatments: 1) corn stover wetted to 40% DM and ensiled (SV), 2) corn stalklage, harvested at 40% DM and ensiled (ST), 3) corn stalklage plus lactobacillus (STL; SiloKing at 0.225 kg/ton applied at bagging), or 4) corn stalklage plus propionic acid (STPA; Silage Savor plus at 0.5 kg/ton applied at bagging). Corn stover (71.5% NDF, 6.12% CP, and 5.88% lignin) was harvested on October 20^th, after dry corn (88% DM). Corn stalklage (68.3% NDF, 6.24% CP, and 5.39% lignin) was harvested on September 22^nd, after harvesting high moisture corn (HMC; 77% DM) . Diets were fed for 85 d, and contained 25% corn plant residue, 30% modified wet distillers grain with solubles (MWDGS), 35% HMC, and 10% supplement (DM basis). From d 86 to 186, all steers were fed a common finishing diet that contained 20% silage, 20% MWDGS, 50% HMC, and 10% supplement (DM basis). In Exp. 2, composite corn plant residue samples (SV, ST, STL and STPA) from Exp. 1 were incubated in 2 ruminally fistulated steers for 12, 24, 36 and 48 h to determine in situ DM disappearance (DMD) and NDF disappearance (NDFD). There were no treatments effects (P ≥ 0.19) on ADG, DMI and G:F from d 0 to 85. During the first 85 d, when fed 25% of corn residue, steers gained 1.69, 1.80, 1.74, and 1.67 kg/d when fed SV, ST, STL, and STPA, respectively. There were no carry-over effects (P ≥ 0.66) of treatment from d 86 to 186; thus, there were no effects (P ≥ 0.78) of treatment on overall steer performance for the entire 186 d. Yield and quality grade distributions, HCW, marbling, back fat, ribeye area and dressing percentage also did not differ (P ≥ 0.14) among treatments. There were no effects of treatment on DMD (P = 0.40) and NDFD (P = 0.34) over time. Average NDFD at 48 h were 27.39, 30.59, 32.50, and 29.45% for SV, ST, STL, and STPA, respectively. Feeding wetted corn stover resulted in similar ruminal fiber degradation, and steer growth and carcass performance as feeding corn stalklage, harvested after HMC harvest.

Keywords: corn stover, growing cattle, stalklage