Incompetent cervix and pneumouterus in a maiden mare

This case report describes an uncommon case of a congenitally incompetent cervix and a resulting pneumouterus in a 5‐year‐old maiden Quarter Horse mare. The mare was presented for artificial insemination at the Clinic for Animal Reproduction, Freie Universität Berlin, Germany. Routine vaginal and rectal examinations revealed a shortened cervix of 3 cm length and a dilated uterus filled with a considerable amount of air. During ultrasonographic examination, ovaries of normal size with regular cyclic activity were detected. Chromosomal analysis could not confirm any genetic anomalies such as an expected XO karyotype. The mare was excluded from breeding due to its anatomical constitution.