The rabbit vagina is a cylindrical, musculo-membranous duct forming the final segment of the female reproductive tract. It connects the external opening (vulva) to the internal reproductive organs. This structure serves two primary roles: receiving sperm during copulation and providing the channel for birth. The rabbit’s reproductive anatomy differs significantly from many other common mammals.
Unique Anatomical Features
The internal anatomy of the female rabbit, or doe, features a specialized structure known as a duplex uterus. This setup is characterized by two completely separate uterine horns that run parallel. Each uterine horn functions independently and possesses its own cervix, differentiating the rabbit from species with a single uterine body.
These two distinct cervices open into a single, common vaginal canal. The vagina is relatively long and saccular, often measuring between six and fourteen centimeters. The tissue lining the canal is not uniform throughout its length.
The upper two-thirds of the vagina, closer to the cervices, are lined by a simple columnar epithelium with ciliated and microvillous cells. This lining suggests an active role in the internal environment. Conversely, the lower third, near the exterior, is lined by a stratified squamous epithelium. The urethra enters the vaginal canal midway, at the vaginal vestibule.
Function in Mating and Kindling
The vagina plays an active role in the rabbit’s unique reproductive process, starting with copulation. Rabbits are induced ovulators, meaning the physical act of mating triggers the release of eggs. This stimulation leads to a hormonal cascade, with ovulation occurring approximately ten to thirteen hours after the brief 20- to 40-second mating.
The vagina serves as the site for the deposition of the male’s semen, a rapid process facilitated by the doe’s receptive posture. The specialized epithelial lining of the upper vagina is thought to assist in sperm viability and transport. The two cervices remain closed by muscular plugs, only opening to allow sperm passage into the respective uterine horns.
During parturition, known as kindling, the vagina transforms into the birth canal for the kits. The two cervices relax to permit the movement of the young from the separate uterine horns into the single vaginal pathway. Kindling is a quick event, typically lasting around thirty minutes, after which the young pass through the vagina and out the vulva.
Common Health Conditions
Abnormal discharge from the vulva is the most common outward sign of a reproductive tract problem, as healthy does should not exhibit discharge. Uterine adenocarcinoma is a highly aggressive cancer that can affect up to 80% of unspayed does over six years old. The discharge associated with this cancer is often serosanguineous, meaning it is thin and blood-tinged, stemming from bleeding tissue inside the uterus.
A second frequent issue is pyometra, an infection causing pus accumulation within the uterine horns. This condition may present with a thick, purulent, yellow-gray vaginal discharge. Both pyometra and adenocarcinoma can cause a general decline in health, including lethargy, decreased appetite, and abdominal enlargement due to the swollen uterus.
Vaginitis, inflammation or infection confined to the vagina, can also cause discharge, but it is less common than uterine issues. Any sign of discharge requires immediate veterinary attention, as these conditions are progressive and can be life-threatening. Ovariohysterectomy, or spaying, is the recommended treatment for uterine disease and prevents cancer and pyometra in younger rabbits.