Isolated and combined causes of equine dystocia

Abstract Background Dystocia is not common in horses, but is life-threatening for both mare and foal. For this reason, veterinary research is dependent on up-to-date data for optimising dystocia management. In addition, knowledge about the prognosis of dystocia cases is necessary for providing advice to animal owners. The present retrospective study of equine dystocia is intended to enrich the existing data set with up-to-date information. For the first time, the focus is on which causes of dystocia occur alone or in combination. Over a period of 10 years, 72 cases of dystocia were analysed using a standardised, predetermined diagnosis code. Results Of 72 cases of dystocia, an isolated cause of dystocia was identified in 31 cases (43%) and 41 animals showed a combination of two or more causes (57%). Foetal causes were significantly more common at 95.7% (95% confidence interval = [87.8%, 99.1%]) than maternal causes at 4.4% (95% confidence interval = [0.1%, 12.2%]) (p < 0.0001). Incorrect posture of the foetal forelimbs and head was the most common combination at 22% (9/41). The most common isolated cause of dystocia was found to be the incorrect posture of the foetal forelimbs (22.6% – 7/31). A fetotomy was performed in 68% of cases of dystocia (49/72). A caesarean section or an extraction was performed in 13.9% (10/72) of the cases. No obstetric procedures were performed in 3 of 72 cases of dystocia (4.2%). These mares died before obstetric care was provided. Nine mares (12.5% – 9/72) were not discharged alive after dystocia. 73 foals were born in 72 cases of dystocia (one twin pregnancy). 55 foals were already dead before veterinary treatment began. In relation to the total number of births in which the foetus was alive at the start of obstetric care, the foetal mortality rate was 61.1% (11/18) and 88.9% (16/18) by the time the mare was discharged. Conclusions It has been shown for the first time that combined causes of dystocia are more common in horses than isolated causes of dystocia. Neonatal mortality remains high, meaning that the timely detection and treatment of dystocia has the highest priority.