Incidences and risk factors for prolapse removal in Spanish sow herds

•1% of sows were removed due to prolapses.•60% of prolapse cases were removed during first 0–4 weeks after farrowing.•Sows with gestation of 113 days or less were at risk of having a prolapse.•High parity sows were at high risk of having uterine prolapses.•Sows farrowing two or more stillbirths were at risk of having rectal prolapses. Prolapses in sows are an emerging concern in pig production. The objectives of this study were to estimate the incidence rate of prolapses and to determine risk factors associated with prolapse occurrences. Data included 905,089 service records in 819,754 parity records of 155,238 sows from 144 swine herds in Spain. Producers were required to record a removal reason, including type of prolapse. A 1:4 matched case-control study was carried out to investigate prolapse risk factors, and piecewise exponential models were applied to the data. The following factors were assessed: parity, number of services, service season, weeks after service, prior gestational length, total number of piglets born, and number of stillborn and mummified piglets. Almost 1% of sows (0.8%) were removed due to prolapses (95% confidence interval: 0.76, 0.85), and the annualized incidence rate for all prolapse cases was 3.8 cases per 1000 sow-years (95% confidence interval: 3.59, 4.01). Significant factors were the 16th week after service, being in parity 3 or higher, re-service, servicing in summer, autumn or winter, shorter gestational length, fewer piglets born and more stillborn piglets (P ≤ 0.04). For example, the prolapse incidence was 30.6 times higher at 16 weeks after service than during the first 14 weeks (P