Efficacy and outcome of foaling augmented with oxytocin using mammary calcium and pH criteria to guide the timing of augmentation

Augmentation of parturition can be used to advance labor in mares to occur at a time when personnel is available to assist if necessary. We performed a retrospective study to determine the efficacy and safety of augmentation to manage foalings. Augmentation was performed with 3 IU oxytocin i.v. when mammary calcium concentrations were >= 250 ppm, mammary secretion pH <= 6.5, and the mare showed impending signs of parturition. Augmented parturitions (n = 19) were compared with three different control groups. The three control groups were: 1) Time Match control (n = 37) which were non-augmented foalings in the barn during the same time period; 2) Mare Match control (n = 32) which were the non-augmented parturitions of the augmented mares in previous years; and 3) Historic Match control (n = 165) consisted of foalings that occurred from 2006 to 2016 in the facility. All augmented mares foaled within two h with an average of 44 min (range 20-75) after oxytocin injection. The interval between foaling and the foal standing was shorter in augmented parturitions compared with historic match controls. The interval between foaling and the foal nursing was longer with augmented parturitions compared with time match and historic match controls. Duration of fetal membrane retention was not different between all groups. Augmentation of imminent parturition is potentially a safe and effective treatment for mares and foals. Implementation of augmentation as a routine procedure may increase the likelihood of enteral administration of colostrum to foals.