Mare's Genital Tract
This is a diagram of a mare's genital tract. It is T-shaped, the ovaries are kidney bean shaped due to ovulation fossa. The cervix is muscular in the mare and changes dramatically in response to steroid hormones, present at different stages of the mares cycle. A frenulum present in the ventral or dorsal portion of the portio-vaginalis of the cervix. The cervix contains some folds which are an extension of the endometrial folds of the uterus. The endometrial folds of the uterus are parallel to the length of the uterus. The vagina is separated from the vestibule by a vestibular vaginal ring (hymen). The opening to the bladder, the urethra, is located on the ventral floor of the cranial portion of the vestibule, at the base of this vestibular vaginal ring. The perineum of the female is formed by the vulvar lips and the muscular tissue below these vulvar lips. The clitoris is in the ventral portion of the vulva.
This whole reproductive tract is supported by a broad ligament, the broad ligament contains blood vessels and nerves. The broad ligament is divided into three parts. The ovary is suspended by the mesovarium, the mesosalpinx supports the oviduct. The mesometrium is that broad portion that suspends the uterus within the abdominal cavity. In the mare, an oviduct papilla is present between the isthmus of the oviduct and the uterus. The oviduct papilla acts like a sphincter in the mare preventing ascending infections. Salpingitis, or inflammation of the oviduct, is uncommon in the mare.
Three structures are important in preventing ascending infection of the uterus? The cervix is one, the vestibular vaginal ring, and the vulvar lips with the muscular tissue supporting them. If any of these are compromised the mare will then be prone to uterine infection. Pregnancy and parturition provide great opportunity for trauma to these three barriers.
Cow's Genital Tract
The cow's ovaries are oval, a mature follicle is usually 2.0 centimeters in diameter, smooth and fluctuant. A corpus luteum, if present, will distort the shape of the ovary and greatly enlarge it.
A cornuate uterus with a small uterine body can be located in the pelvic canal or be positioned cranially over the pelvic brim in the abdominal cavity. Her uterine body is short and she has long uterine horns that curve ventrally. The entire genital tract is supported by the broad ligament.
The bovine cervix has 3-5 muscular, cartilaginous transverse annular folds and is difficult to dilate manually in the cycling cow. The cow has cartilaginous rings in her cervix which rarely relax appreciably.
Sow's Genital Tract
Mature sow ovaries have numerous follicles and/or corpora lutea and a mulberry-like appearance. The mesosalpinx almost completely covers the ovary in the ovarian bursa.
The sow has a short uterine body and long tortuous uterine horns that are freely moveable due to the long broad ligaments.
Her long cervix has a thick wall with transverse folds. The cervix is contiguous with the vagina.
The long vestibule has thick vulvar lips. There is a cul-de-sac on each side of the cranial floor of the vestibule.