A novel method for parturition induction in cattle using vaginal wall stimulation.

Induction of parturition in cattle is used to reduce labor in calving management, prevent dystocia due to oversized calves, and treat prolonged gestation. Conventional pharmacological induction methods rely on prostaglandin F2α (PGF2α), dexamethasone, estrogens, and oxytocin (OXT), either individually or in combination. However, variability in the induction-to-calving time (ICT), including a prolonged ICT, remains a major challenge. In this study, we developed a novel method for inducing parturition by combining conventional pharmacological induction with vaginal wall stimulation (VWS), which artificially activates the Ferguson reflex and enhances endogenous OXT secretion. We compared its effects on the ICT, the incidence of dystocia, and neonatal vitality with those of pharmacological induction alone to evaluate the efficacy and safety of this new approach. Japanese Black breeding cows (n = 15 per group) in the control group received PGF2α, dexamethasone, and estriol 1 day before expected calving, while the VWS group received the same agents followed by VWS approximately 24 h later. Compared with the control group, the VWS group showed a statistically significant reduction in the ICT and decreased ICT variability. Given the statistically significant promotion of labor observed in the VWS group, this improvement in ICT may be attributable to the labor-inducing effect of VWS. Additionally, no significant differences were observed in obstetrical intervention rates or neonatal calf vitality. This novel approach may facilitate more rapid and consistent parturition while maintaining safety for both cows and newborn calves, and may contribute to improving calving management efficiency and reducing the workload of livestock producers.