title: The effects of regrouping on behavioral and production parameters in finishing swine.
abstract: Three trials involving 396 pigs were conducted to determine the effects of regrouping finishing swine (83.8 +/- .69 kg) on weight gain and behavior during the subsequent 2-wk period. The methodology between Trials 1, 2, and 3 differed primarily in the total number of pigs tested (72, 144, and 180, respectively) and the number of pigs per pen (3, 3 or 5, and 5, respectively). In all trials, like-sexed pigs were moved into a new pen location and allotted to one of three treatments: 1) a group of familiar pen mates (Control), 2) a group composed of unfamiliar pigs (Mixed), and 3) pigs mixed with strangers for 24 h and then reunited with original pen mates for the duration of the trial (Mixed 24 h). In the pooled analysis, control pigs gained faster (P < .01) than Mixed pigs (.87 and .77 kg/d, respectively) over the 2-wk period. Mixed 24-h pigs were intermediate in gain (.80 kg/d), indicating that the most severe aggression normally observed during the first 24 h accounts for only a portion of the setback. Apparently the negative social stress associated with being in the presence of unfamiliar pigs persisted beyond the first 24 h and was sufficient to limit weight gain over the 2-wk period. Time spent fighting was reduced from 1.72 min/h during a 6-h period on d 1 to .39 min/h during a 3-h period by d 2 in the Mixed group. Fighting was still observed in the Mixed pens 8 d after regrouping (.23 min/h), indicative of ongoing social conflicts.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Sciences, University of Illinois, Urbana 61801.
authors.forename: J M
authors.initials: JM
authors.lastname: Stookey
authors.forename: H W
authors.initials: HW
authors.lastname: Gonyou
mesh_terms: D000374:Aggression; D000821:Animal Feed / Q000592:standards; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005260:Female; D008297:Male; D011897:Random Allocation; D012727:Sex Characteristics; D013312:Stress, Physiological / Q000503:physiopathology / Q000662:veterinary*; D013315:Stress, Psychological / Q000503:physiopathology; D013552:Swine / Q000254:growth & development / Q000502:physiology* / Q000523:psychology; D013553:Swine Diseases / Q000503:physiopathology; D015430:Weight Gain / Q000502:physiology*