Observation of dose dependent intravaginal Prostaglandin E2 application in free farrowing sows during parturition – a pilot study

The duration of birth is an important factor influencing the survival of piglets and the health of sows. A prolonged parturition is usually treated with oxytocin, even though several undesirable side effects are described. Therefore, the aim of this study was to evaluate the safety and efficacy of Prostaglandin E2 (PGE2) of different concentrations as an intravaginal applied gel after the birth of the fourth piglet in sows. Twelve sows were randomly allocated to one of four treatment groups: Group I (control group) application of placebo gel; Group II application of 0.5 mg; Group III application of 1.0 mg PGE2; Group IV PGE2 application of 2.0 mg PGE2. Total duration of parturition (time between first piglet and last placenta), piglet interval before and after treatment and placenta expulsion duration (time between first and last placenta) were recorded, and each piglet was scored for meconium staining and vitality. Furthermore, stillborn piglets were categorized into ante-partum and intra-partum deaths. A significant dose-dependent effect of PGE2 after the fourth piglet in a linear regression model with group I, II and III on the total duration of parturition and the placenta expulsion duration was detected. An increase of the PGE2 dosage from 0 to 1 mg significantly reduced the total duration of parturition (group I: 553.7 ± 114.2; group II:456 ± 167.9; group III: 284.7 ± 40.5; p-value: 0.02) and placenta expulsion duration (group I: 364 ± 120; group II: 289 ± 144.1; group III: 119 ± 46.13; p-value: 0.03). Although no further significant differences between the groups using ANCOVA and a linear regression model including all groups were detected, severe meconium staining in more than 10% of piglets was observed in group II and IV. Moreover, piglets of group IV showed oedematous and haemorrhagic umbilical cords, lethargy and anoxia after treatment, and intra-partum deaths were recorded. The best outcome for the sows and piglets was achieved using the 1 mg PGE2 dosage, whereas the other dosages showed more negative side effects, impairing the health and welfare of the animals. The results of this study can be used for further studies with larger sample sizes.