Use of oxytocin in penned sows and its effect on fetal intra-partum asphyxia

The objective of the present study was to evaluate in penned sows the effect of two commercial oxytocin products on umbilical cord pathology, degree of asphyxia and intra-partum mortality. This study included 120 sows divided in three groups of 40 animals with eight animals for parities one to five per subgroup, respectively. Group 1 (G1) or control received saline solution while oxytocin groups (G2) and (G3) were injected at the onset of fetal expulsion with two oxytocin products. The doses of oxytocin were as follow: Primiparous sows weighing less than 130 kg received 20 IU; multiparous sows weighing 130–180 kg received 30 IU, and those above 250 kg, 40 IU. Piglets born alive and/or dead were classified at birth using a subjective scale based on the degree of meconium staining on skin. Umbilical cords of intra-partum stillbirths (IPS) were classified as adhered or ruptured and subdivided into four categories: without pathological changes, edematous, congested and hemorrhagic. Result analyses revealed significant differences (P<0.01) between groups 1 and 2, and 1 and 3 regarding the following traits: expulsion interval (min) (X: G1 27.7; G2 22.6; G3 22.2), IPS with a severe stain degree (X: G1 0.10; G2 0.45; G3 0.50), IPS with ruptured umbilical cords (X: G1 0.07; G2 0.42; G3 0.47), and detectable heartbeats in IPS (X: G1 0.27; G2 0.25; G3 0.22). Treatment with oxytocin reduced the duration of the expulsion of the fetus, increased the number of IPS with ruptured umbilical cords and with severe meconium-stain degree and reduced the number of fetuses with inspiration attempts. Furthermore, the use of this hormone increased the need for obstetric assistance due to increased frequency of dystocia.