SOW CULLING AND MORTALITY IN COMMERCIAL SWINE BREEDING HERDS

Six months of production data from 18 commercial swine breeding PBherds were used to describe reason-specific removal rates and the amount of time lost between farrowing and removal for each removal reason. There were 774 females removed during the 6-month analysis period. The removal rate for the study period was 25.0%, equivalent to an annual rate of 50%. Four major reason groups accounted for 70% of all removals: reproductive failure, degenerative problems, locomotor problems and death. Reproductive failure was the most likely removal reason across all parity groups except parity ≥7, in which degenerative problems were much more likely and reproductive failure ranked second. The average time required from farrowing to removal across all reason groups was 78 days. Reproductive failure clustered at >10 weeks, with an average time to removal of 128 days. Removals for degenerative problems clustered at Weeks 4-6 and at >10 weeks, with an average time to removal of 57 days. Death clustered at Week 1 and at >10 weeks, with an average time to removal of 72 days. Locomotor problems clustered at Weeks 5-8, with a second peak at > 10 weeks; the average time to removal was 58 days. Most females were removed involuntarily, and as the replacement rate increased a higher proportion of all removals were involuntary. © 1990.