title: Performance, carcass composition, and blood hormones and metabolites of finishing pigs treated with porcine somatotropin in hot and cold environments.
abstract: Two experiments were conducted to assess the ability for recombinant porcine somatotropin (rpST)-treated pigs to perform and cope with the demands of hot and cold environments. In the first experiment, finishing pigs were exposed to either a thermoneutral (TN; 18 to 21 degrees C) or a hot environment (H; 27 to 35 degrees C) for 35 d. In the second experiment, pigs were exposed to a TN or cold environment (C; 5 to 15 degrees C). The rpST delivered by a 6-wk prolonged-release system had no effect on ADG, whereas both H and C reduced ADG by 29.4 and 11.8%, respectively. In the first experiment, rpST-treated pigs consumed 17.6% less feed than control pigs, whereas rpST-treated pigs in H consumed 24.4% less feed than rpST-treated pigs in TN. Overall feed/gain ratios through the first 4 wk of both studies were improved by 21.8 and 14%, respectively, by rpST (P < .05) and were 24.3% poorer in C (P < .05) than in H. The changes in blood concentrations of pST, IGF-I, and IGF-II associated with rpST were not influenced by the different environments. Total body composition of rpST-treated pigs had increased amounts of protein (P < .05) and decreased amounts of fat (P < .05); H further reduced fat (P < .05). The C resulted in reduced protein content (P < .05). No evidence of thermal imbalance due to rpST was found as assessed by rectal temperature, respiration rate, and heat production estimated by indirect calorimetry and chemical analysis.
authors.affiliation: Animal Physiology Unit, ARS, USDA, Columbia, MO 65211.
authors.forename: B A
authors.initials: BA
authors.lastname: Becker
authors.forename: C D
authors.initials: CD
authors.lastname: Knight
authors.forename: J J
authors.initials: JJ
authors.lastname: Veenhuizen
authors.forename: G W
authors.initials: GW
authors.lastname: Jesse
authors.forename: H B
authors.initials: HB
authors.lastname: Hedrick
authors.forename: C A
authors.initials: CA
authors.lastname: Baile
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D001806:Blood Urea Nitrogen; D001823:Body Composition / Q000187:drug effects*; D001831:Body Temperature; D001833:Body Temperature Regulation / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000097:blood; D013006:Growth Hormone / Q000097:blood / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007335:Insulin-Like Growth Factor II / Q000032:analysis; D008297:Male; D008460:Meat / Q000592:standards*; D011994:Recombinant Proteins / Q000494:pharmacology; D012119:Respiration; D013552:Swine / Q000097:blood / Q000254:growth & development*; D013696:Temperature; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D015430:Weight Gain / Q000187:drug effects*
chemical_list: D005230:Fatty Acids, Nonesterified; D011994:Recombinant Proteins; D014284:Triiodothyronine; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone; D013974:Thyroxine