LAUSR

BackgroundOur objectives were 1) to compare reproductive performance across parities and lifetime performance of parity 1 sows in six weaning-to-first-mating interval groups (WMI 0–3, 4, 5, 6, 7–20 and 21 days or more), 2) to determine the recurrence patterns and repeatability of WMI, and 3) to quantify factors associated with the probability of parity 1 sows having WMI 4 days. Examined data comprised 691,276 parity and 144,052 lifetime records of sows in 155 Spanish herds, served between 2011 and 2016. Mixed-effects models were applied to the data. Variance components analysis determined WMI repeatability.ResultsProportions of parity 1 sows with WMI 0–3, 4, 5, 6, 7–20 and 21 days or more were 4.1, 30.0, 38.4, 7.9, 12.7 and 6.9%, respectively. Of the parity 1 sows with WMI 0–4 days, 43.3–60.5% had WMI 4 days in later parities, whereas 33.9–48.9% of those with WMI ≥5 days had WMI 5 days; WMI repeatability was 0.11. Parity 1 sows with WMI 4 or 5 days had 0.3–2.1 days shorter WMI in later parities than those with WMI ≥7 days (P <  0.05). Parity 1 sows with WMI 4 or 5 days also had 0.6–2.1 more annualized lifetime piglets born alive than those with WMI ≥7 days (P <  0.05). Notably, parity 1 sows with WMI 4 days had 0.3 more annualized lifetime piglets born alive than those with WMI 5 days (P <  0.05).ConclusionThe WMI in parity 1 could be a useful predictor for subsequent reproductive performance and lifetime performance of sows.