Associations Between First Parity Wean-to-Service Interval and Sow Lifetime Productivity Traits

This study aimed to 1) investigate associations between first parity wean-to-service interval (WSI) and sows’ lifetime reproductive traits and 2) identify cut-off values for WSI associated with lifetime traits. Data collected in 3,900-sows of farrow-to-finish commercial farm in Yucatan, Mexico. Lifetime productivity records including parity number at culling (NPC), lifetime number piglets born alive (LNBA) from parity two until culling, lifetime non-productive days (LNPD) and length of productive life (LPL) for sows were used. Association between WSI and sow productive traits were evaluated using general linear models, including year and season as categorical fixed effects and WSI as a continuous linear and quadratic predictors. Cut-off values for WSI were estimated using regression tree analysis. WSI was associated (P < 0.05) with LNBA (linear = -0.62 ± 0.025; quadratic 0.02 ± 0.008) and NCP (linear = -0.04 ± 0.018). Similarly, an association (P < 0.05) was observed between WSI and LNPD (linear = 2.81 ± 0.687; quadratic -0.05 ± 0.023). Cut-off values for WSI varied according to each of the predicted variables: WSI > 5 days would translate into longer 13 more days of LPL, WSI < 7 days would increase LNBA by two extra pigs, WSI ≥ 9 days increases NCP by 0.2 parities, and WSI < 10 days would mean 24 fewer LNPD. Shorter WSI during the first parity was associated with improved lifetime productivity traits. The estimated cut-off values for WSI could be used by producers, to decide when to implement strategies to improve management.