Persistence and recovery of reproductive underperformance across successive parities in commercial sows.

BACKGROUND

Reproductive underperformance is commonly used to inform sow retention and replacement decisions, yet a single poor reproductive cycle may not necessarily indicate persistent reproductive failure. This study evaluated longitudinal patterns of reproductive recovery following low-performing parities and determined whether recovery was associated with previous performance history and reproductive stage.

METHODS

Historical production data comprising 15,699 farrowing records from 4,498 sows in a commercial breeding herd between 2020 and 2026 were retrospectively analysed. Reproductive underperformance was operationally defined as ≤10 piglets weaned (PW) per litter, corresponding to the 25th percentile of the observed distribution, while recovery was defined as >10 PW at the immediately subsequent consecutive parity.

RESULTS

Among 2,948 low-performance episodes with an observed immediately subsequent consecutive parity, 62.4% recovered, whereas 37.6% remained below the threshold; recovery estimates were therefore conditional on observation to the subsequent consecutive parity. Recovery declined from 63.8% following a first observed low-performing parity to 58.0% after two consecutive observed low-performing parities and 46.9% after three or more. After adjustment for reproductive and temporal factors, two consecutive observed low-performing parities were associated with 27% lower odds of recovery (OR = 0.73, 95% CI: 0.58-0.91; P = 0.005), while three or more were associated with 45% lower odds (OR = 0.55, 95% CI: 0.36-0.85; P = 0.007), compared with a first observed low-performing parity. Adjusted recovery probabilities following repeated underperformance were 61.0%, 55.1%, and 41.3% during early (P1-P2), prime (P3-P5), and later (P6-P8) reproductive stages, respectively; however, the overall stage × performance-history interaction was not significant (P = 0.121), and stage-specific patterns were therefore considered exploratory.

DISCUSSION/RECOMMENDATION: These findings indicate that a single observed low-performing parity is frequently transient, whereas repeated underperformance is associated with progressively reduced recovery. Longitudinal reproductive history may therefore provide more informative evidence for sow retention decisions than the most recent litter alone, although external validation across commercial herds is required.