Objective: To describe the characteristics and frequency of gross uterine anomalies in cats and dogs undergoing elective ovariohysterectomy.
Design: Prospective and retrospective case series.
Animals: 53,258 cats and 32,660 dogs undergoing elective ovariohysterectomy at 26 clinics in the United States and Canada during 2007.
Procedures: Clinics prospectively reported gross anomalies and submitted tissues from abnormal reproductive tracts identified during surgery. Records from a feral cat spay-neuter clinic were evaluated retrospectively.
Results: Suspected congenital anomalies of the uterus were identified in 0.09% (49/53,258) of female cats and 0.05% (15/32,660) of female dogs. Uterine anomalies identified included unicornuate uterus (33 cats and 11 dogs), segmental agenesis of 1 uterine horn (15 cats and 3 dogs), and uterine horn hypoplasia (1 cat and 1 dog). Ipsilateral renal agenesis was present in 29.4% (10/34) of cats and 50.0% (6/12) of dogs with uterine anomalies in which kidneys were evaluated. Mummified ectopic fetuses were identified in 4 cats with uterine anomalies. Both ovaries and both uterine tubes were present in most animals with uterine anomalies.
Conclusions and clinical relevance: Urogenital anomalies were twice as common in cats as in dogs. Identification of uterine developmental anomalies in dogs and cats should trigger evaluation of both kidneys and both ovaries because ipsilateral renal agenesis is common, but both ovaries are likely to be present and should be removed during ovariohysterectomy.