Retrospective study of dystocia in mares at a referral hospital.

Summary Reasons for performing study: The period between the onset of dystocia and its resolution has an important bearing on fetal outcome. There are few published data on which to base decisions regarding optimum management of cases in practice. Objectives: To evaluate and compare the effects of a coordinated dystocia management protocol (CDMP) with that of a previous protocol of random management on time to resolution and outcome in both an emergency dystocia referral population of mares (referred emergency cases: EM) and in a population of mares residing in hospital due to high risk pregnancy (HRP) concerns that then experience dystocia at parturition. Methods: Retrospective study performed at a university hospital referral centre of cases presenting from 1991–2004 divided into Group 1 (pre-CDMP) and Group 2 (CDMP). Results: Medical records of 71 cases with dystocia were retrieved and data recorded. For referred emergency cases (EM), time from hospital presentation to resolution decreased significantly by 32 min (P = 0.03) after institution of CDMP. Survival rate of mares at discharge was 86%. Survival of EM foals was low, with 10% in Group 1 and 13% in Group 2, surviving to discharge. For EM foals delivered alive, survival to discharge was 30% and 43% in Groups 1 and 2, respectively. Median Stage II was significantly (P < 0.001) different at 71 and 282 min for EM foals delivered alive vs. those not alive at delivery, respectively. Median duration of Stage II was also significantly (P < 0.001) different between EM foals surviving and not surviving to discharge, at 44 and 249 min, respectively. Survival of HRP dystocia foals to discharge was 79%. Conclusions: Although CDMP reduced the time from presentation at the hospital to resolution significantly for EM, total duration of Stage II for EM was unchanged, as was foal outcome. Potential relevance: Very early referral of mares with dystocia to referral centres with dystocia management protocols may improve fetal outcome as increased duration of Stage II in the horse affects fetal outcome negatively.