PSLBI-26 Purebred-crossbred genetic parameters for sow pelvic organ prolapse

Abstract The incidence rate of sow pelvic organ prolapses (vaginal, uterine, or rectal) has increased in recent years. Using a relatively large dataset, this study aimed to estimate the genetic parameters for sow pelvic organ prolapse in purebred and crossbred sow herds. Data were collected from 2018 to 2023 in 32 purebred and 8 crossbred farms, including records from 75,162 purebred sows of a single maternal line and 18,988 two-way crossbred commercial sows. Pelvic organ prolapse was categorized as either normal or prolapsed at the individual sow level, with average incidence rates of 1.81% and 3.93% for purebred and crossbred, respectively. Prolapses in purebred and crossbred were considered two different traits in the model. The bivariate model included fixed effects of parity group and region, and random effects of contemporary group, additive genetic and residual. The contemporary group was defined as the farm, mating year, and month at the first parity. Genetic parameters were estimated using BLUPF90+ with the AIREML option. Heritability estimates were 0.09 for purebreds and 0.11 for crossbreds, with a genetic correlation of 0.83. Results suggested that selection strategies aimed at reducing prolapse incidence in purebred herds will also benefit crossbred sow herds. Due to the low heritability, reducing the incidence of prolapse will have to rely on genetic improvement and enhanced animal management strategies.