Effects of oxytocin and carbetocin on farrowing performance

During sow parturition, there is need for an alternative uterotonic to oxytocin with less potency so piglets are not at risk of hypoxia and stillbirth. In this study, there was examination of carbetocin, a longer lasting analogue of oxytocin, and whether the lesser contractile force and duration resulting as a consequence of this treatment would improve piglet survivability. Following delivery of the first piglet, sows were serially assigned by parity to receive injections of 10 IU oxytocin (n = 35), 0.07 mg carbetocin (n = 36), or serve as a non-injected control (n = 30). The incidence of dystocia and stillbirths was recorded. To estimate liveborn piglet viability, umbilical cord blood samples were obtained from pigs 1, 2, 3 and 8, 9, 10, and lactate content was quantified to assess hypoxia during delivery. A blood sample collected at 24 h was assayed for total protein in plasma (%) as an indicator of colostrum intake. Treatment with oxytocin and carbetocin reduced farrowing duration (P = 0.023) and sows treated with carbetocin had piglets with the least umbilical cord blood lactate (P  = 0.008) and plasma protein (P = 0.005) concentrations. These data indicate carbetocin has the efficacy to accelerate piglet delivery and reduce piglet hypoxia, although the reason for reduced plasma protein with this treatment remains unexplained.