title: Effects of moisture, roller setting, and saponin-based surfactant on barley processing, ruminal degradation of barley, and growth performance by feedlot steers.
abstract: Two experiments were conducted to study the effects of six processing techniques for barley grain in a 3 x 2 factorial arrangement of grain conditions and roller settings on ruminal degradation of the grain (Exp. 1) and on growth performance by 138 feedlot steers (n = 23 per treatment; Exp. 2). Dry barley (11% moisture, D barley), barley tempered to 20% moisture (M barley), and barley tempered with 60 mL/t of surfactant-based tempering agent (GrainPrep, Agrichem, Inc., Anoka, MN; MS barley), were each rolled at two roller settings selected from preliminary tests. The settings selected for the study were RD, the roller position that had yielded optimally processed D barley, and RMS, the setting that had yielded optimally processed MS barley. Setting RMS was tighter than RD. Barley rolled at the RMS setting was more extensively processed (i.e., had a lower [P < 0.001] processing index, PI), had lighter (P < 0.001) volume weight, thinner (P < 0.001) kernels, and fewer (P < 0.001) whole kernels compared with setting RD. Tempering did not affect (P > 0.05) PI, percentage of whole kernels, or kernel thickness at either roller setting. The processing characteristics of tempered barley were unaffected (P > 0.05) by surfactant. The extent of in situ DM disappearance (ISDMD) was higher (P < 0.01) in grain rolled at setting RMS compared with RD. At both roller settings, tempering reduced (P < 0.05) ISDMD between 4 and 24 h of ruminal incubation. Steers fed RMS-rolled barley had lower (P < 0.001) DMI, slightly lower (P = 0.084) ADG, but increased (P < 0.05) gain:feed (G:F) compared with steers fed RD-rolled barley. Tempering did not affect (P > 0.05) ADG, DMI, or G:F during backgrounding, but improved (P < 0.01) these variables during finishing. Surfactant improved (P < 0.05) G:F but not DMI or ADG. The improvement in G:F was most pronounced when setting RMS was used. The optimal PI values calculated from performance data were numerically greater for the backgrounding diet than for the finishing diet. Steers fed M or MS barley had heavier (P < 0.01) hot carcasses and thicker (P < 0.05) fat cover but lower (P < 0.05) dressing percentages than steers fed D. When the feed barley was rolled at setting RMS, steers fed MS barley produced heavier (P < 0.05) carcasses than those fed M. Tempering with or without surfactant increased performance by feedlot steers compared with not tempering. Diet composition and degree of barley processing mediated this effect.
authors.affiliation: Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada T1J 4B1. wangy@agr.gc.ca
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: D
authors.initials: D
authors.lastname: Greer
authors.forename: T A
authors.initials: TA
authors.lastname: McAllister
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000254:growth & development* / Q000378:metabolism; D004063:Digestion; D004435:Eating; D005511:Food Handling / Q000379:methods*; D001467:Hordeum / Q000378:metabolism; D008297:Male; D008460:Meat / Q000592:standards; D012417:Rumen / Q000378:metabolism*; D012503:Saponins / Q000008:administration & dosage / Q000494:pharmacology; D013501:Surface-Active Agents / Q000008:administration & dosage / Q000494:pharmacology*; D014867:Water / Q000378:metabolism; D015430:Weight Gain
chemical_list: D012503:Saponins; D013501:Surface-Active Agents; D014867:Water