title: Effects of the Programmed Nutrition Beef Program on feedlot performance and carcass characteristics.
abstract: The objective of this study was to examine the effects of alternative finishing strategies on feedlot performance and carcass characteristics. Beef steers (64 pens; 8 steers/pen) were allocated to a randomized complete block design with a 2 × 2 factorial treatment arrangement. Factor 1 consisted of diet, with cattle fed a conventional (CON) diet or a diet consisting of Programmed Nutrition Beef Program (PN) supplements. The PN treatment included Programmed Nutrition Beef Receiver fed from d 1 through 20 of feeding and Programmed Nutrition Beef Finisher fed from d 21 to harvest. Factor 2 evaluated the presence (EGP+) or absence (EGP-) of exogenous growth promotants (ExGP) in the production system. Steers in the EGP+ treatments were initially implanted with Component E-S, reimplanted with Component TE-IS, and fed 400 mg·animal·dof ractopamine hydrochloride for the final 28 d before harvest. Steers were harvested on d 175, and strip loins were removed from 2 carcasses selected at random from each pen for transport to Kansas State University. One 1.27-cm-thick steak was removed from the anterior face for proximate and long-chain fatty acid analysis. There were no diet × ExGP interactions ( > 0.10) for feedlot performance except for DMI ( = 0.02). Steers in the PN/EGP+ treatment consumed more feed than all other treatments ( < 0.05). Both diet and ExGP affected DMI ( < 0.05), with PN and EGP+ steers consuming more feed than their contemporaries. Gain:feed and ADG were unaffected ( > 0.10) by diet, but ExGP improved these measures ( < 0.01). There were no diet × ExGP interactions for carcass characteristics except KPH fat and percentages of yield grade 3 and 4 carcasses ( < 0.05). Diet affected total incidence of liver abscesses because PN steers had a greater ( = 0.05) incidence of liver abscesses than steers in the CON treatment. Diet did not affect the other carcass characteristics ( > 0.10). Use of ExGP increased ( < 0.05) HCW, LM area, and 12th-rib fat but did not affect ( > 0.10) marbling score. Using ExGP reduced the percentage carcasses grading Premium Choice ( < 0.05). No diet × ExGP interactions or diet effects were detected for long-chain fatty acid profiles ( > 0.10). Use of ExGP increased ( < 0.05) the ratio of saturated:unsaturated fatty acids. In summary, the alternative feeding strategy presented in this study produced similar feedlot performance and carcass characteristics compared with a conventional feedlot system.
authors.forename: K J
authors.initials: KJ
authors.lastname: Phelps
authors.forename: J S
authors.initials: JS
authors.lastname: Drouillard
authors.forename: J S
authors.initials: JS
authors.lastname: Jennings
authors.forename: B E
authors.initials: BE
authors.lastname: Depenbusch
authors.forename: C L
authors.initials: CL
authors.lastname: Van Bibber-Krueger
authors.forename: K A
authors.initials: KA
authors.lastname: Miller
authors.forename: M A
authors.initials: MA
authors.lastname: Vaughn
authors.forename: D D
authors.initials: DD
authors.lastname: Burnett
authors.forename: J M
authors.initials: JM
authors.lastname: Gonzalez
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001823:Body Composition / Q000187:drug effects*; D002417:Cattle / Q000254:growth & development*; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D007615:Kansas; D008297:Male; D009752:Nutritional Status; D010627:Phenethylamines / Q000494:pharmacology; D015430:Weight Gain / Q000187:drug effects
chemical_list: D000318:Adrenergic beta-Agonists; D010627:Phenethylamines; C060897:ractopamine