Effects of feeding corn plant residues during the growing phase on steer growth performance and feedlot economics

Feeding harvested corn crop residues (CCR) to cattle has become increasingly common; however, the poor quality of mature CCR presents nutritional challenges. Therefore, the objectives of these studies were to evaluate the effects of feeding CCR harvested at 2 maturities and the effects of 2 silage additives, Silage SAVOR Plus (propionic acid-based additive) or Silo-King (lactobacillus-based additive), on in situ fiber disappearance, cattle growth performance and carcass characteristics, and economic traits of growing cattle. A total of 128 Angus × Simmental steers (initial BW = 327 ± 40 kg) were allotted to 20 pens and fed 4 treatments in diets that contained 25% forage: (1) corn stover, wetted to 40% DM and ensiled; (2) corn stalklage, harvested at 40% DM and ensiled (STK); (3) STK plus Silo-King; or (4) STK plus Silage SAVOR Plus. Corn stover was harvested 186 d after planting after harvesting dry corn. Corn stalklage was harvested 158 d after planting after harvesting high moisture corn. Growing diets contained CCR at 25% inclusion (DM basis) and were fed from d 0 to 85. From d 86 to 186, steers were fed a common finishing diet. Corn crop residue samples were incubated in 2 ruminally fistulated steers to determine in situ DM disappearance and NDF disappearance. There were no effects of treatment on in situ DM disappearance (P = 0.40) or in situ NDF disappearance (P = 0.34). There were no treatment effects (P ≥ 0.19) on steer growth performance from d 0 to 85 and from d 86 to 186; thus, there were no effects (P ≥ 0.14) of treatment on overall steer performance, carcass characteristics, and economic traits for the entire 186 d. Feeding mature CCR resulted in similar ruminal fiber degradation, steer growth, carcass performance, and economic traits when compared with immature CCR in diets fed to growing steers, and there was no benefit of additive inclusion.