title: Byproduct yields of serially harvested calf-fed Holstein steers fed zilpaterol hydrochloride.
abstract: A 2 × 11 factorial treatment structure was applied in a completely randomized experimental design to investigate differences in noncarcass tissue among serially harvested Holstein steers. Steers ( = 110) were randomly assigned to 1 of 2 dietary treatments: a ration supplemented with zilpaterol hydrochloride (ZH) fed at a rate of 8.3 mg/kg DM for 20 d followed by a 3-d withdrawal or a control ration with no ZH included in the diet. Within treatment, steers were assigned to harvest groups of 254, 282, 310, 338, 366, 394, 422, 450, 478, 506, or 534 d on feed (DOF) prior to initiation of the trial. Cattle fed ZH realized an empty BW (EBW) increase ( ≤ 0.03) of 2.8% (644.2 vs. 626.4 kg [SEM 5.4]) and a HCW increase of 5.0% (429.1 vs. 408.4 kg [SEM 4.0]) with a concomitant 12% reduction (45.1 vs. 51.2 kg [SEM 3.1]) in gastrointestinal contents and 2.1 percentage unit increase in dressed carcass yield (62.1 vs. 60.0% [SEM 0.01]). Additionally, ZH supplementation decreased (P ≤ 0.03) the absolute weight of the liver and kidneys by 0.3 and 0.1 kg, respectively. When noncarcass components were expressed on an empty body basis (g/kg EBW), reductions ( ≤ 0.01) in the limbs (18.8 vs. 19.5 g/kg EBW [SEM 0.1]), hide (81.1 vs. 78.1 g/kg EBW [SEM 0.7]), liver (14.2 vs. 13.2 g/kg EBW [SEM 0.2]), kidneys (2.6 vs. 2.3 g/kg EBW [SEM 0.04]), small and large intestines (74.9 vs. 69.6 g/kg EBW [SEM 1.2]), and gastrointestinal tract (119.8 vs. 113.4 g/kg EBW [SEM 1.3]) were observed with ZH supplementation. Additionally, there was a tendency ( = 0.07) for the proportion of total offal to be reduced (253.2 vs. 247.4 g/kg EBW [SEM 2.5]) with ZH supplementation. Empty BW and HCW linearly increased ( < 0.01) by 1.16 and 0.758 kg/d ( < 0.01), respectively, with additional DOF. The weight of the liver and intestines linearly increased ( < 0.01) by 0.007 and 0.133 kg/d ( < 0.01), respectively, with additional DOF. These data indicate the magnitude of change in noncarcass tissues that can be expected when calf-fed Holstein steers are supplemented with ZH.
authors.forename: N D
authors.initials: ND
authors.lastname: May
authors.forename: T J
authors.initials: TJ
authors.lastname: McEvers
authors.forename: L J
authors.initials: LJ
authors.lastname: Walter
authors.forename: J A
authors.initials: JA
authors.lastname: Reed
authors.forename: J P
authors.initials: JP
authors.lastname: Hutcheson
authors.forename: T E
authors.initials: TE
authors.lastname: Lawrence
mesh_terms: D018663:Adrenergic Agents / Q000494:pharmacology; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D001835:Body Weight; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D008297:Male; D014297:Trimethylsilyl Compounds / Q000494:pharmacology*; D015430:Weight Gain
chemical_list: D018663:Adrenergic Agents; D014297:Trimethylsilyl Compounds; C475840:Zilpaterol