Maternal hemoglobin during late gestation and neonatal hemoglobin are associated with piglet oxygenation and early survival in hyper-prolific sows under tropical conditions.

Modern swine breeding programs have prioritized litter size, resulting in so-called hyper-prolific sows that farrow >16 piglets per litter. This increased uterine occupancy increases fetal competition for placental nutrients and oxygen, potentially impairing neonatal hematologic development and early physiological competence. While maternal anemia has been associated with adverse farrowing outcomes, the independent contribution of neonatal hemoglobin concentration to functional adaptation remains to be characterized. This study investigated the relationship between maternal hemoglobin concentration during late gestation and neonatal functional outcomes in 115 Landrace × Yorkshire sows and 1792 piglets under tropical commercial conditions. Sows were classified as anemic (Hb < 10 g/dL, n = 62) or non-anemic (Hb ≥ 10 g/dL, n = 53) at day 109 of gestation. Piglets were similarly categorized as anemic (Hb < 10 g/dL) or non-anemic (Hb ≥ 10 g/dL) at birth. Neonatal measurements included hemoglobin concentration, oxygen saturation, blood glucose, birth weight, colostrum intake, and survival at 24 h and 3 d postpartum. Mixed-effects models adjusted for litter-level clustering in the data were employed. Maternal hemoglobin status did not predict piglet anemia after controlling for sow as a random effect (P = 0.44), indicating predominant within-litter variability. However, anemic piglets exhibited decreased birth weight (P = 0.006), reduced SpO2 (P = 0.0002), lower colostrum intake (P = 0.0003), lower glucose concentration (P < 0.0001), and higher mortality rate at 24 h (P = 0.015) and 3 d (P = 0.001) compared with non-anemic littermates. Neonatal hemoglobin concentration was positively associated with oxygen saturation, glucose homeostasis, and postnatal growth independent of maternal status. These findings indicate that neonatal hemoglobin concentration is a key physiological regulator of oxygen transport during the perinatal transition, and that compromised systemic oxygenation rather than maternal anemia alone underlies impaired early adaptation and reduced survival in piglets born to hyper-prolific sows.