Factors for Culling Risk due to Pregnancy Failure in Breeding-Female Pigs

A high occurrence of culling due to pregnancy failure disturbs the flow of pig production and decreases productivity of female pigs in commercial breeding herds. The objective of the present study was to quantify changes in culling risk due to pregnancy failure [CRPF] in breeding-female pigs due to variation in outdoor climate and production factors. The data included 240 143 parity records and 54 858 lifetime records of female pigs in 99 commercial herds located in humid subtropical and continental climate zones. The weather data were acquired from 21 local meteorological observatories close to the studied herds. Mean daily average temperature [Tmean] and relative humidity [RH] during the 21-day pre-mating period for each female were matched with the female’s reproductive data. Generalized linear mixed-effects models were applied to the data. Mean by-parity and lifetime CRPF (± SE) were 3.6 ± 0.04% and 20.1 ± 0.17%, respectively. An increase in by-parity CRPF was associated with higher Tmean, higher gilt age at first-mating, fewer pigs born alive and prolonged weaning-to-first-mating interval (P < 0.05), but not with mean RH (P > 0.18) or weaning age (P ≥ 0.31). For instance, CRPFs for female pigs in parities 0-5 were 1.5-2.4% higher at Tmean 30 °C than at 10 °C (P < 0.05). Therefore, producers are recommended to closely monitor at-risk female pigs and apply advanced cooling equipment to reduce heat stress, and provide appropriate management to prevent increased CRPF in female pigs.