Effect of removal and remixing of lightweight pigs on performance to slaughter weights

Department of Animal Science, Iowa State University, Ames, Iowa, United States
Journal of Animal Science (Impact Factor: 2.11). 05/2002; 80(5):1166-72.
Source: PubMed


Two experiments were conducted to determine the effect of lightweight pig removal and remixing on performance to slaughter. Experiment 1 was a growing-finishing trial utilizing a total of 900 pigs (26.2+/-0.1 kg initial weight) that were sorted and remixed at a mean replicate BW of 72 kg. Experiment 2 was a wean-to-finish trial (17 d mean wean age; 4.8 kg +/- 0.1 BW) utilizing 225 barrows with sorting and remixing occurring 3 wk after weaning. Treatments were 15 pigs/ pen from initial weight to slaughter (15S), 20 pigs/pen from initial weight to time of sort and remix and then reduced to 15 pigs/pen (20/15), and 15 pigs/pen from time of sort and remix to slaughter comprised of the five lightest pigs from each of three 20/15 pens per replicate (15M). Space allocation was 0.56 m2/pig from 26 to 70 kg and 0.74 m2/pig thereafter in Exp. 1. In Exp. 2, pen size was fixed at 2.44 x 4.27 m. In Exp. 1, there was no effect (P > 0.20) of treatment on performance prior to 70 kg. Least squares means for ADG from time of sort and remix to first pig removal from a pen for slaughter at 113 kg were 0.93, 0.87, and 0.91 kg/d for the 20/15, 15M, and 15S treatments, respectively (P < 0.05). When comparing the population represented by the 20/15 + 15M treatments vs the 15S population, there was no difference (P > 0.20) in ADG, ADFI, feed conversion, or carcass lean content. In Exp. 2, pigs in the 20/15 treatment grew slower (P < 0.05) than 15S pigs for the first 21 d (0.20 vs 0.22 kg/d, respectively) with a lower ADFI (P = 0.06) and no difference in feed conversion. When comparing the population represented by the 20/15 + 15M treatments vs the 15S population after sorting and remixing, there was no effect (P > 0.15) of experimental treatments on ADG, ADFI, feed conversion efficiency, carcass lean content, or daily lean gain. These results suggest that removal of lightweight pigs and remixing of the removed pigs into pens of similar-weight pigs is ineffective in improving the overall performance of a population of pigs during the postweaning period.

Download full-text


Available from: Dale W Rozeboom
  • Source
    • "There is a distinct lack of data available on lifetime performance of light BW pigs. As a result, research on how to manage weight variation is limited, with few practical suggestions that have been proven to be effective (O'Quinn et al., 2001; Brumm et al., 2002). The aim of this paper was to identify risk factors associated with poor lifetime performance in pigs, paying particular attention to the effect BiW and WW have on subsequent performance. "
    [Show abstract] [Hide abstract]
    ABSTRACT: During the production period from birth to slaughter there are some pigs that grow markedly slower, despite conditions which seem to support the growth of their contemporaries. This reduction in growth inevitably leads to weight variation within a group, causes difficulties with management and results in system inefficiencies. By understanding the factors which contribute to poor growth, the performance of these slow growing pigs might be improved, thereby decreasing the overall variability at slaughter. The aim of this paper was to analyse the factors associated with poor growth performance in pigs from birth to slaughter, determine the effect of piglet birth weight (BiW) and weaning weight (WW) on lifetime growth, and investigate the capacity of small piglets to compensate for any BW deficit. Two industry databases, with individual data for approximately 40,000 and 90,000 pigs respectively, and containing weight profiles and relevant variables, were analysed. BW at birth, weaning, intermediate and finishing stages were available, as well as sex, month of birth and litter size information (number born alive, total born including still born), sow parity number and length of gestation. Absolute and relative growth rates, based on adjusted weight for age, were calculated for each time interval and 3 types of analysis were performed: a logistic regression, a continuous linear plateau model and a weight category analysis. For both datasets poor absolute and relative growth from birth to final BW was associated with low BiW (P < 0.001), low WW (P < 0.001), sex (P < 0.001), breed code (P < 0.001) and month of birth (P < 0.001). The linear plateau model suggested that the relationship between BiW and lifetime growth was not linear beyond 1.91 (database 1) or 1.84 (database 2) kg; the same applied to the relationship between WW at 21 d and finish BW (FW) growth, which was not linear beyond 7.53 kg. Finally, the weight category analysis revealed that piglets with the lowest BiW were able to exhibit compensatory growth from BiW to FW with 74 (database 1) and 82% (database 2) moving at least 1 BW 3 category. It is concluded that growth performance to slaughter is not solely reliant on pig BiW, with WW also playing a critical role. Additionally, piglets with BiW below the average are capable of some degree of compensatory growth; this provides the opportunity for managing them so as to improve their lifetime growth.
    Full-text · Article · Jul 2013 · Journal of Animal Science
  • Source
    • "However , sorting by BW usually involves mixing unfamiliar pigs, which induces aggression and the associated negative effect on animal welfare. Other studies (O'Quinn et al., 2001; Brumm et al., 2002) did not demonstrate that sorting by BW at early growing phase reduces variation in market weight. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A study was conducted to evaluate the effects of social familiarity and initial BW variation at mixing on performance and welfare of pigs born to group-housed lactating sows. A total of 180 pigs from 24 litters were used in a random design with 4 treatments in a 2 x 2 (social familiarity x initial BW uniformity) factorial arrangement. Pigs were born in group-farrowing rooms where they mingled in large groups of 66 to 80 pigs from 10 d of age. At 8 wk of age (BW=23+/-3.1 kg), pigs were allocated to 20 pens of 9 pigs (5 castrated males and 4 females) in a grow-finish room, with 5 pens assigned to each of 4 treatment combinations without consideration of relatedness. Familiar groups consisted of pigs from 1 farrowing room, and unfamiliar groups consisted of 3 pigs from each of 3 different farrowing rooms. Uniform BW groups were formed by using the middle 2 quartiles, and variable BW groups by using the heaviest and lightest quartiles of pigs. Aggression and activity behavior were directly observed by scan or continuous sampling during a period of 4 h on the first 3 d, d 7, and d 14 after grouping. Injury scores were assessed on all pigs immediately before and 48 h after grouping. Body weight gain and apparent feed intake were measured every 2 wk for 14 wk. Aggression in familiar groups was minimal throughout the observation periods. Compared with that in familiar groups, total duration of fighting was greater in unfamiliar groups on d 0 (upon grouping, 48.5 vs. 0.5+/-10.88 s/pig(-1).4 h(-1); P<0.001) and on d 1 (10.8 vs. 0.4+/-3.24 s/pig(-1).4 h(-1); P<0.05) after grouping. Unfamiliar pigs had greater injury scores (6.6 vs. 1.8+/-0.28; P<0.001) and spent less time eating on d 0 (5.1 vs. 8.8+/-0.92% of total observation time; P<0.01) after grouping compared with familiar pigs. The ADG and ADFI were decreased in unfamiliar groups during the initial 6 wk, but not for the entire 14-wk period in comparison with familiar groups. Body weight variation did not affect behavior and performance in familiar groups but increased aggression-induced injuries in unfamiliar groups. The results indicated that grouping unacquainted pigs derived from large groups induced overt aggression, associated injuries and initial reduction in performance, which causes welfare concerns on mixing pigs born to group-housed lactating sows.
    Full-text · Article · Dec 2008 · Journal of Animal Science
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Printout. Thesis (M.S.)--University of Illinois at Urbana-Champaign, 2002. Includes bibliographical references.
    Full-text · Article ·
Show more