Blood haemoglobin concentrations in free farrowing sows and their piglets are associated with farrowing performance characteristics and sow traits.

Haemoglobin concentration (HbC) in sows and/or their piglets might influence the farrowing process. The aim of this study was to investigate the association between the HbC of breeding sows and piglets and their performance characteristics at farrowing in a free farrowing system. In total 103 sows and their 1615 piglets were included. The investigated parameters included the HbC in all sows and the HbC in approximately 5 piglets per litter (n = 496). In addition, parity, litter size, litter weight, placenta weight, stillbirth rate, piglet expulsion duration, farrowing duration and other sow and piglet traits were evaluated. The mean HbC of the sows was 106.2 ± 10.36 g/l and of the litter was 93.6 ± 9.6 g/l. The univariant analysis revealed that sows with a HbC <100 g/l (low HbC) had a significantly higher median parity number (5.0, p = 0.003), litter size (18, p < 0.001) and placenta weight (4.9 kg, p < 0.001) compared to sows with a HbC ≥100 g/l (high HbC) (3.0; 15; 3.9 kg). The median piglet expulsion duration was significantly longer in low HbC sows (290min p = 0.005; compared to high HbC sows (224min). No significant correlation could be determined between the HbC of the sows and the HbC of their offspring (Pearson correlation: r = 0.124, p = 0.263). In the multivariable regression model, pre-partum HbC in sows decreased with an increase in litter size (beta = -0.88), was 6.62 g/l higher in low parity sows (1 + 2 vs > 2) and tended to be 3.02 g/l higher in sows that received obstetrical intervention. This study showed that the HbC of the sows and the piglets were significantly associated with several performance characteristics. It could serve as a useful indicator in farrowing management, contributing to better farrowing outcomes and promoting improved health and vitality in piglets.