Genital Tract Pathology in Female Pet Rabbits (Oryctolagus cuniculus): a Retrospective Study of 854 Necropsy Examinations and 152 Biopsy Samples

Genital tract disorders, especially uterine disorders, are the most common conditions of the female pet rabbit (Oryctolagus cuniculus); however, there have been few large studies of diseases of the female genital tract of this species. The present study examined diseases of the ovaries, Fallopian tubes, uterus and vagina, retrospectively over a period of 22 years, and included 854 full post-mortem examinations of female pet rabbits and 152 female genital tract biopsy samples. The age distribution of uterine neoplasia, endometrial hyperplasia and uterine inflammation was determined in the post-mortem cases. Uterine disorders were a common finding, occurring in 26.8% of all full necropsy examinations and in almost all genital tract biopsy samples. Uterine tumours (n = 205) were the most common uterine pathology, with adenocarcinoma being the most frequent tumour type. Metastasis was found in 46.2% of rabbits with uterine adenocarcinomas diagnosed at post-mortem examination, with metastatic spread to the lung occurring in 79.1% of these animals. The second most common uterine pathology was endometrial hyperplasia, which was glandular-cystic in most cases. The incidence of uterine tumours and endometrial hyperplasia increased with age, while endometrial hyperplasia was found more commonly in slightly younger animals. In contrast, uterine inflammation, the third most common finding, was found predominately in young to middle-aged rabbits. Ovarian disorders were found rarely at post-mortem examinations (3.3% of all animals), but comprised 16.9% of biopsy samples. Of these, ovarian cysts, especially follicular cysts, and secondary tumours were found most frequently. Disorders of the Fallopian tube and the vagina were found in <1% of cases and should be considered rare.