Good prognosis for survival to hospital discharge in a group of horses with uterine prolapse treated at a veterinary medical teaching hospital.

Objective: To describe uterine prolapse, predispositions, and outcomes in mares treated between 1988 and 2019.
Animals: 24 mares with uterine prolapse.
Procedures: Clinical records were retrospectively reviewed, and follow-up information was gathered. The Mann-Whitney U test and Fisher exact test were used to analyze results for history and outcome variables for potential association with mare survival to hospital discharge. The χ2 test was used to compare breed distribution.
Results: Age was known in 23 mares (median, 11.1 years). For 15 mares with exact known parity, the median parity was 3 births (range, 1 to 13 births). For 22 mares, the maiden status was known (7 [32%] maiden; 15 [68%] multiparous). Breed distribution differed significantly between mares with uterine prolapse and all mares treated at the Veterinary Medical Teaching Hospital. Arabians were overrepresented in the uterine prolapse group (7/24 [29%]), compared with all mares treated (4,174/44,474 [9%]). Uterine prolapse occurred within 2 hours after parturition for 10 of 11 mares with known foaling times, after dystocia for 7 mares, and after abortion for 4 mares. Seventeen of 23 (74%) mares survived to hospital discharge. Acute hemorrhage was the most frequent cause of death. There were no correlations between mare survival to hospital discharge and mare parity or age, foal sex, retained fetal membranes, sepsis, or maiden status. Colts were overrepresented in foals with a known sex (12/17).
Clinical Relevance: Results indicated a breed predisposition to uterine prolapse, with Arabian mares overrepresented among affected mares. No characteristics correlated with mare survival to hospital discharge.