An experiment was conducted to determine the effects of heavyweight pig removal and remixing on performance. The experiment used a total of 450 pigs (31 kg initial BW) that were sorted and remixed at a mean replicate BW of 73 kg. Treatments were 15 pigs/pen from initial BW to slaughter (15S), 20 pigs/pen from initial BW to time of sort and remix, then reduced to 15 pigs/pen (20/ 15), and 15 pigs/pen from time of sort and remix to slaughter, comprised of the 5 heaviest pigs from each of three 20/15 pens per replicate (15M). Space allocation was 0.56 m2/pig to the day of remixing and 0.74 m2/pig thereafter. There was no effect (P > 0.1) of treatment on ADG before 73 kg BW when pens were the experimental units. There was no effect (P > 0.1) of treatment on ADG or feed conversion to slaughter BW following removal and remixing using the contrast 20/15 + 15M vs. 15S. The average of the replicate for 20/15 and 15M was used as the experimental unit in a second statistical analysis. Daily feed was less (P = 0.079) from placement to 73 kg BW for the 20/15 + 15M population vs. the 15S population resulting in a lesser (P = 0.067) overall ADG (0.875 vs. 0.887 kg/d, respectively) with no effect (P > 0.1) on feed conversion or CV sample population BW. Removal and remixing of heavyweight pigs at a midpoint in the growth process had minimal effects on performance to slaughter and CV for BW at slaughter.
Bibliographical notePublisher Copyright:
© 2006 American Registry of Professional Animal Scientists.