Outcome of performance-based removal and replacement decisions in commercial swine herds

Abstract

To evaluate the success of removal and replacement decisions in commercial swine herds when sow removal was attributed to problems with fertility, fecundity, or old age. Retrospective case-control study. 3,000 sows removed from 3 commercial swine herds (case sows), 3,000 matched control sows retained in the herds, and 3,000 replacement gilts. Control sows were included to generate an estimate of reproductive performance that could have been expected had case sows been retained in the herds. Control sows and replacement gilts were followed up until the next farrowing or until removed from the herd, and reproductive performance, calculated as number of pigs born alive per mated female per year, was compared between groups. In 2 of the 3 herds, reproductive performance was significantly higher for replacement gilts than for control sows matched with case sows removed for reasons of fertility, and in all 3 herds, reproductive performance was significantly higher for replacement gilts than for control sows matched with case sows removed for reasons of fecundity. In the 2 herds with case sows removed because of age, reproductive performance did not differ significantly between replacement gilts and control sows. The odds of greater performance among replacement gilts relative to control sows ranged from 1.305 to 1.955 for removals attributed to fertility, 1.305 to 1.955 for removals attributed to fecundity, and 1.000 to 3.999 for removals attributed to age. Results suggested that performance-based removal and replacement programs in commercial swine herds may not yield the anticipated results.