Flint corn grain processing and citrus pulp level in finishing diets for feedlot cattle

J Anim Sci. 2016 Feb;94(2):665-77. doi: 10.2527/jas.2015-9459.

Abstract

Four trials were conducted to evaluate the effects of flint corn processing and the replacement of corn with citrus pulp (CiP) in diets for Nellore feedlot cattle. In a 103-d finishing trial, 216 Nellore bulls (350 ± 24 kg initial BW) were used in a randomized complete block design with a 2 × 4 factorial arrangement of treatments. Factors included 2 processing methods, either ground corn (GC) or steam-flaked corn (FC), with CiP replacing each corn type at 4 levels (0, 25, 50, and 75% of DM). All diets contained 12% sugarcane bagasse and 88% concentrate (DM basis). Treatments were also evaluated in metabolism trials, in which 10 ruminally cannulated Nellore steers (389 ± 37 kg) were assigned to 2 independent but simultaneous 5 × 5 Latin squares, each using 1 method of corn processing (GC and FC). Interactions ( < 0.05) between corn processing and CiP inclusion level were observed for final BW, DMI, ADG, G:F, and HCW. With FC-based diets, added CiP linearly decreased final BW ( = 0.04), whereas with GC-based diets, added CiP quadratically increased final BW ( = 0.002). With FC-based diets, the inclusion of CiP linearly increased DMI ( = 0.03) and linearly decreased ADG ( = 0.03) and G:F ( = 0.001). Increasing CiP in GC-based diets quadratically increased DMI ( = 0.001), ADG ( = 0.005), and HCW ( = 0.003). In FC-based diets, CiP inclusion had no effect on HCW ( = 0.21). Dressing percent, LM area, and 12th-rib fat were not affected by diet ( ≥ 0.05). For steers fed GC diets, CiP inclusion in the diet quadratically decreased the molar proportion of isovalerate ( = 0.001) but linearly increased ruminal butyrate ( = 0.006). No differences ( ≥ 0.16) were observed for total VFA concentrations, acetate:propionate ratio, and ruminal NH-N as CiP replaced GC. For steers fed FC diets, the molar proportion of acetate linearly increased ( = 0.002) whereas the proportion of propionate was linearly decreased ( < 0.001), resulting in a linear increase ( = 0.001) in the acetate:propionate ratio. Replacing corn with CiP linearly reduced NEm ( = 0.001) and NEg ( < 0.001) of FC-based diets but did not affect ( = 0.15) NE values of CG-based diets. Steam flaking flint corn improved cattle performance in this trial more than has been reported for dent corn in the published literature.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed / analysis*
  • Animal Nutritional Physiological Phenomena
  • Animals
  • Cattle / metabolism*
  • Cellulose / chemistry
  • Citrus / chemistry*
  • Diet / veterinary*
  • Food Handling / methods*
  • Male
  • Minerals / metabolism
  • Steam
  • Zea mays / chemistry*
  • Zea mays / metabolism

Substances

  • Minerals
  • Steam
  • Cellulose
  • bagasse