The course of parturition in two sow genotypes and two hut designs under free-range conditions

Abstract High piglet mortality remains a major challenge in outdoor pig production. The use of hyper prolific sow genotypes giving birth to large litters may prolong parturition and cause parturition-related problems under outdoor conditions where birth assistance cannot easily be provided. Therefore, the aim of the current study was to investigate the course of parturition and maternal protectiveness in two sow genotypes and two farrowing hut designs. Secondly, the aim was to investigate if the course of parturition (parturition duration and posture changes during parturition) constituted a significant risk for pre- and postnatal piglet mortality. Sows gave birth in four batches of 10–11 Danbred Landrace × Yorkshire crossbred sows (in first and then second parity) and 10–12 Topigs Norsvin TN70 sows (in first and then second parity). Within batch, six sows of each genotype gave birth in a communal hut, and the remaining sows in each batch in standard A-frame huts. Neither genotype nor hut design significantly affected parturition duration. Sows spent the majority of time lying in lateral position during the first 3 h of parturition (median 120.0 min, range 0–180 min) although they changed posture 23 times (median, range 0–110) during these three hours. The behaviour (time spent in lateral and sternal position, standing and number of posture changes) of the sows during the first 3 h of parturition depended on both sow genotype and parity. Furthermore, Topigs Norsvin sows stayed closer to their piglets during piglet processing, but sow agitation score was unaffected by genotype. A longer parturition increased the risk of having at least one stillborn piglet in the litter (P = 0.003) and the risk of postnatal mortality (P = 0.051). The hourly number of posture changes during parturition did, however, not influence postnatal mortality.