title: Effects of immunological castration and distiller's dried grains with solubles on carcass cutability and commercial bacon slicing yields of barrows slaughtered at two time points.
abstract: Male pigs were randomly assigned to a castration method at birth and allotted to 48 pens (28 pigs/pen). Physically castrated (PC) barrows were castrated at 2 d of age; immunologically castrated (IC) barrows were administered Improvest (GnRF analog diphtheria toxoid conjugate; Zoetis, Kalamazoo, MI) at 16 and 20 wk of age. Distiller's dried grains with solubles (DDGS) feeding strategies included either 0% DDGS (control), 30% DDGS (30% DDGS) fed from 6 wk of age to slaughter, or 30% DDGS fed from 6 wk of age to second dose of Improvest and then fed 0% DDGS until slaughter (withdrawal). Four barrows closest to the median pen weight at 4.5 wk after second dose were selected for evaluation; two were randomly selected and slaughtered at 5 wk and the other two at 7 wk after second dose. Data from each slaughter time were analyzed independently as a 2 × 3 factorial design with pen as the experimental unit. At 5 wk after second dose, bone-in lean cutting yields were 2.63% units greater (P < 0.01) in IC when compared to PC. Bellies were thicker (P < 0.01) and tended to have greater belly flop distances (P = 0.07) in PC compared to IC, however iodine values (IV) were not altered (P = 0.84). Carcass traits (P ≥ 0.10), cutting yields (P ≥ 0.43), and fresh belly characteristics (P ≥ 0.08) were minimally affected by DDGS feeding strategy. Bacon slicing yields (percentage of green weight) were 6.10% units less (P < 0.01) in IC compared with PC. At 7 wk after second dose, bone-in lean cutting yields were 1.57% units greater (P = 0.03) in IC compared with PC. Distiller's grains feeding strategy had no effect (P ≥ 0.83) on boneless carcass cutting yields in IC; while in PC, these yields were 2.32% units less (P < 0.02) in control-fed barrows when compared to other feeding strategies (castration method × feeding strategy; P = 0.03). Bellies from PC tended to be thicker (P = 0.07) and have similar flop distances (P = 0.44) and IV (P = 0.54) when compared with IC. Iodine value was greater (P = 0.03) in 30% DDGS-fed barrows compared with control-fed barrows. Bacon slicing yields (percentage of green weight) were 4.27% units less (P = 0.05) in IC compared with PC. These data suggested that while bacon slicing yield was reduced in IC barrows fed control and 30% DDGS compared with PC barrow counterparts, withdrawal of DDGS improved bacon slicing yields of IC barrows.
authors.affiliation: Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana 61801.
authors.forename: M A
authors.initials: MA
authors.lastname: Tavárez
authors.affiliation: Department of Animal Sciences, The Ohio State University, Columbus 43210.
authors.forename: B M
authors.initials: BM
authors.lastname: Bohrer
authors.affiliation: Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
authors.forename: M D
authors.initials: MD
authors.lastname: Asmus
authors.affiliation: Zoetis, Kalamazoo, MI 49007.
authors.forename: A L
authors.initials: AL
authors.lastname: Schroeder
authors.affiliation: Sugar Creek Packing Co., Washington Court House, OH 43160.
authors.forename: R J
authors.initials: RJ
authors.lastname: Matulis
authors.affiliation: Department of Animal Sciences, The Ohio State University, Columbus 43210.
authors.forename: D D
authors.initials: DD
authors.lastname: Boler
authors.affiliation: Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana 61801 adilger2@illinois.edu.
authors.forename: A C
authors.initials: AC
authors.lastname: Dilger
mesh_terms: D000367:Age Factors; D000821:Animal Feed; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D004168:Diphtheria Toxoid / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D008297:Male; D008460:Meat / Q000592:standards*; D009919:Orchiectomy / Q000379:methods / Q000662:veterinary*; D013552:Swine
chemical_list: D004168:Diphtheria Toxoid; D007987:Gonadotropin-Releasing Hormone
keywords: DDGS; Improvest; bacon; cutting yields; pig