title: Effects of corn processing, dietary roughage level, and timing of roughage inclusion on performance of feedlot steers.
abstract: In Trial 1, 108 crossbred steer calves (initial BW 295 kg) were allotted to 12 pens and used in a 186-d feedlot trial to determine the effects of increasing or decreasing roughage level on feedlot performance and carcass characteristics. Four dietary treatments were investigated: 1) 85% concentrate diet fed for 186 d, 2) 100% concentrate diet fed for 186 d, 3) 85% concentrate diet fed for 84 d followed by a 100% concentrate diet for the remaining 102 d, and 4) 100% concentrate diet for 84 d followed by an 85% concentrate diet for the remaining 102 d. Corn silage was added as roughage. During the first 84 d, level of dietary concentrate did not affect (P > .10) ADG. Steers switched to the 85% concentrate diet for the last 102 d had higher (P < .05) DMI than those fed the 100% concentrate diet; they did not exhibit an increase in ADG. Finishing phase feed efficiency was highest (P < .05) for steers continually fed 100% concentrate, lowest (P < .05) for steers continually fed 85% concentrate, and intermediate for steers whose concentrate level was switched during the trial. Carcass characteristics were not affected (P > .10) by concentrate level regimen. In Trial 2, 108 crossbred steer calves (initial BW 319 kg) were allotted to 12 pens and used in a 158-d trial to determine whether feedlot performance could be enhanced by manipulating roughage level and grain processing. Factors investigated were staged increases in concentrate level (70 to 85 to 100%) vs staged decreases in concentrate level (100 to 85 to 70%) and whole vs rolled high-moisture corn. Corn silage was added as roughage. Diet concentrate levels were changed on d 56 and 112. During the first 56 d, steers fed 70% concentrate diets grew 11% faster (P < .05) and consumed 19% more feed (P < .05) than those fed 100% concentrate diets. Steers fed rolled corn gained 8% faster (P < .06) and were 7% more efficient (P < .06) than those fed whole corn. During the last period (d 113 to 158), ADG was not affected (P > .10) by concentrate level or corn processing. Although increasing roughage during the feeding period increased feed intake in these trials, steer performance was not enhanced. Processing high-moisture corn did not affect feedlot performance.
authors.affiliation: Department of Animal Sciences, Ohio Agricultural Research and Development Center, and The Ohio State University, Wooster 44691-4096, USA. loerch.1@osu.edu
authors.forename: S C
authors.initials: SC
authors.lastname: Loerch
authors.forename: F L
authors.initials: FL
authors.lastname: Fluharty
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000254:growth & development*; D004043:Dietary Fiber; D002149:Energy Intake; D008297:Male; D008460:Meat; D009919:Orchiectomy; D009929:Organ Size; D015430:Weight Gain; D003313:Zea mays