Abstract Body condition management in early-parity sows is critical for long-term herd productivity and sow longevity. Our objective was to evaluate how body condition and reproductive traits measured in parity one gilts relate to retention through parity three and lifetime pigs born alive. Data were collected from a commercial farm from August 2024 to November 2025. Gilts (n = 1,238; PIC Camborough) with complete parity one farrowing and weaning records were classified as complete (remained in the herd through parity three; n = 848) or incomplete (removed earlier; n = 390). Caliper scores at farrowing and weaning, body condition loss during lactation, total born, born alive, stillborn, mummified fetuses, and age at mating were recorded at parity one. Body condition loss was calculated as caliper units at weaning minus caliper units at farrowing. Data were analyzed using logistic regression for retention and linear regression for lifetime productivity. Machine learning models were trained using ten-fold cross-validation with a 70:30 training-to-testing split, including gradient boosting, random forest, elastic net, ridge, lasso, and support vector machines. Variable importance was assessed using SHAP values. Across parities, caliper scores at farrowing increased (P 0.001) from parity one (15.66 units) to parity three (15.97 units), while body condition loss declined (P 0.001) from 2.71 to 1.12 units. Gilts that reached parity three had lower (P 0.001) caliper scores at farrowing (14.97 vs. 15.94 units) and weaning (12.51 vs. 13.13 units) and lost less (P 0.001) body condition during lactation (2.45 vs. 2.81 units) compared with gilts removed before parity three. Stillborn count was slightly higher (P = 0.009) in complete gilts (1.04 vs. 0.85), while total born, born alive, and mummified fetuses did not differ (P 0.10). Logistic regression revealed that each additional unit of body condition loss reduced the odds of completing parity three by 19% (OR = 0.81, P = 0.001). Lower caliper at weaning (OR = 0.73, P = 0.042) and older age at mating (OR = 0.98, P 0.001) also reduced retention probability. Gradient boosting achieved the best classification performance (accuracy = 0.74, specificity = 0.93, sensitivity = 0.24, AUC = 0.72) and predicted lifetime pigs born alive most accurately (R² = 0.40, RMSE = 6.03 piglets). Variable importance analysis identified body condition loss (mean SHAP = 0.40) and age at mating (mean SHAP = 0.31) as the most influential predictors, followed by caliper at farrowing (mean SHAP = 0.13), born alive (mean SHAP = 0.09), and caliper at weaning (mean SHAP = 0.06). In summary, body condition loss during first lactation is the strongest predictor of both retention through parity three and lifetime reproductive output.
García et al. (Wed,) studied this question.
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