A 15-year-old Welsh pony mare presented to Cornell’s Equine Hospital three days following unplanned natural breeding by a horse sized stallion. Immediately following breeding the owner noticed frank blood from the vulva. In the following three days the mare exhibited mild signs of colic, fever, and lack of appetite.

On presentation she was quiet, alert, and responsive. She was normothermic, tachypneic, and estimated at five percent dehydrated. Her phenotype was consistent with equine metabolic syndrome. Abnormalities on serum chemistry were consistent with inflammation, historical anorexia, and metabolic disease. Hemogram abnormalities were consistent with acute severe inflammation and low-grade hemorrhage. Abdominal ultrasound showed a small amount of free fluid with otherwise normal viscera. On transrectal ultrasound a large fluid filled mass consistent with a hematoma was visualized ventral to the rectum. A digital vaginal exam and speculum examination were performed. A large tear in the left cranial portion of the vagina caudal to the cervix was palpated. Just adjacent to the tear were loops of bowel herniating through torn peritoneum.

Abdominocentesis was performed and peritoneal fluid sample was submitted for analysis. There was a high-nucleated cell count (451.2 thous/uL) composed of mostly non-degenerate neutrophils, a number of erythrocytes (52.3 thous/uL), and there was no evidence of infectious organisms or spermatozoa. These findings are consistent with suppurtive inflammation. The main problems identified on history and entering examination included a vaginal and peritoneal tear with secondary peritonitis, possibly septic, moderate dehydration, equine metabolic syndrome, and chronic laminitis increasing the risk of acute recrudescence.

The mare was started on intravenous fluids and placed in the intensive care unit. She was managed medically on broad-spectrum antibiotics for traumatic peritonitis, anti-adhesion therapy, and preventatives to minimize the likelihood of acute laminitis. In addition she was tied in a standing position at all times to allow the vagina to heal without allowing bowel to be herniated into the vaginal canal.

Lateral P3 radiographs were obtained during hospitalization to assess for signs of chronic and acute laminitis. Serial hemograms, abdominal ultrasounds, vaginal exams, and peritoneal fluid analyses were performed to monitor response to therapy and degree of inflammation. With signs of resolution of peritoneal fluid and hemogram abnormalities the mare was discharged on broad-spectrum oral antibiotics and signs to monitor closely for signs of acute laminitis and colic secondary to visceral adhesions. She was readmitted two days later for an impaction colic and acute laminitis. She recovered and was discharged with a favorable prognosis.