Sorting and Mixing Effects in a Wean-to-Finish Facility

2002 University of Nebraska-Lincoln Extension Swine Report. An experiment was conducted to evaluate whether removing and mixing lightweight pigs in a wean-to-finish facility resulted in improved pig performance to slaughter compared to never removing pigs from a pen from weaning to slaughter. Two populations of pigs were compared. The removed and mixed population consisted of pens comprised of 1) 20 pigs per pen with the five lightest pigs removed three weeks after weaning and 2) 15 pigs per pen with the pen comprised of the five lightest pigs from three of the 20 pig pens. The unsorted population consisted of 15 pigs per pen from weaning to slaughter. There was no effect of treatment when comparing populations on daily gain, daily lean gain, carcass lean percentage, daily feed intake or feed conversion efficiency. On day 158 following weaning when the heaviest pigs from both populations were removed for slaughter, pigs in the removed and mixed population were represented in both ends of the pig weight distribution curve, while no pigs from the unsorted population were present in the lightest weight category. Results of this experiment do not support the recommendation that removing and remixing lightweight pigs in a wean-to-finish facility improves performance and decreases variation in pig weight at time of slaughter.