Effects of parasympathominetics on porcine stillbirth.

To study the effect of 2 parasympathomimetic drugs in reduction of incidence of stillborn pigs, 84 sows and gilts were randomly allotted to 3 treatment groups. Single 1-ml injections of isotonic saline solution, carbachol (2 mg/ml), or neostigmine bromide (5 mg/ml) were subcutaneously administered to pigs of groups A, B, and C, respectively. Injections were given midway through parturition in an attempt to hasten the delivery of the last pigs in the litter, where the corresponding incidence of stillbirth is greatest. The mean time of injection was after the birth of 3.5 pigs. Total stillbirths/litter for carbachol-treated (0.23) and neostigmine-treated (0.21) pies were significantly different (P greater than 0.0001) from those for control pigs (0.88). Before injection, stillbirths/litter for control pigs (0.23) were not significantly different from those for carbachol-treated (0.18) or neostigmine-treated (0.12) pigs. After treatment, stillbirths/litter for carbachol-treated (0.06) and neostigmine-treated (0.09) pigs were both significantly different (P greater than 0.0001) from those for saline solution-treated control pigs (0.65). When injected midway through parturition, carbachol and neostigmine reduced stillbirth rate by reducing stillbirths which occur late in farrowing.