Equis ISSN 2398-2977

Vagina: vaginitis

Contributor(s): Philippa O'Brien, Christopher Phillips


  • Cause: pneumovagina, urovagina, vaginal trauma during foaling, contagious equine metritis (CEM), intra-vaginal progesterone-releasing devices.
  • Signs: vaginal discharge, subfertility, straining, fever and depression with necrotic vaginitis.
  • Diagnosis: physical examination, vaginal speculum examination, bacterial culture.
  • Treatment: dependent on cause.
  • Prognosis: usually good except in some severe cases of necrotic vaginitis.



Post-foaling vaginitis

  • Most common following a normal large foaling, a prolonged dystocia   Reproduction: dystocia   or fetotomy   Fetotomy  .
  • Trauma to the vaginal mucosa   Vagina: trauma   may include lacerations, bruising and hematoma formation, complicated by secondary infection, formation of fistulous tracts and abscessation.

Poor perineal conformation

  • Most common in older, multiparous mares.
  • A poor vulval or vestibulovaginal seal allows "windsucking" (aspiration of air into the caudal vagina)   Vulva: conformation  .
  • Cranioventral sloping of the pelvic canal can also allow urovagina   Vestibule: urine pooling  , most common in the early post-partum period or when the mare is in estrous and the perineum and vaginal structures are most relaxed.
  • May also commonly be seen in young Thoroughbred mares with little perineal fat.

Predisposing factors



Post-foaling mares

  • Mild vaginal bruising is often sustained during normal parturition and usually resolves uneventfully.
  • Prolonged pressure on the vaginal walls during dystocia leads to devitalization and necrosis of the mucosa.
  • Vaginal lacerations can occur from fetal manipulations or fetotomy equipment, particularly if there is inadequate lubrication or excessive force used.
  • Vaginal hematomas are susceptible to infection and abscess formation.
  • Opportunistic bacteria are introduced at foaling, including anaerobes such asBacterioidesspp. Delivery of a dead, necrotic fetus increases the likelihood of bacterial contamination.
  • Severe trauma and disruption of the vaginal walls can result in fistulous tracts, with abscess formation (rare) in the pelvic area, on very rare occasions abscesses may dissect through tissue planes into the caudomedial thigh or even the abdomen.
  • Scarring and adhesion of the vaginal walls is a common complication once healing has occurred.
  • Occasionally, life-threatening sequelae such as septic peritonitis   Abdomen: peritonitis  , septicemia, endotoxemia   Endotoxemia: overview   and laminitis   Foot: laminitis   may arise.

Pneumovagina  Vagina: pneumovagina 

  • An ineffective vulvar or vestibulovaginal seal may be the result of genetic conformation, reduced perineal fat, aging, loss of condition or perineal injury.
  • Poor perineal conformation allows influx of air and bacteria to the caudal reproductive tract.
  • The presence of air in the vagina causes a local inflammatory response and blood vessel engorgement.
  • Bacterial contamination (usually from fecal material) can initiate a vaginitis. This may then progress to cervicitis and endometritis if contaminated exudate enters the cervical os.
  • Pooling of urine   Vestibule: urine pooling  may also be present, particularly in older mares. This can also cause a mild vaginitis, with effects on fertility being significant if contaminated urine flows back through the cervix to cause endometritis   Uterus: endometritis - bacterial  .

CEM  Uterus: contagious equine metritis 

  • Infection with the CEM organism,Taylorella equigenitalis  Taylorella equigenitalis  , through venereal transmission or via fomites causes inflammation of the endometrium, cervix and vaginal mucosa, resulting in a grayish vulval discharge.
  • Mares can become carriers once recovered.
  • The disease is notifiable by law in the UK and many other countries.

Intravaginal devices

  • Progesterone-releasing intravaginal devices are sometimes used to manipulate the estrous cycle or hasten first ovulation in transitional estrous.
  • Mild irritation combined with ascending contamination from the exposed string through the vulval lips can cause a mild vaginitis, which tends to resolve spontaneously when the device is removed.


  • Signs of necrotic vaginitis are usually present within 48 h of foaling.
  • Low-grade vaginitis caused by pneumovagina   Vagina: pneumovagina   or urovagina   Vestibule: urine pooling   may be present for years, and may go unnoticed.
  • CEM has incubation period of 8-10 days and vaginal discharge persists for 13-17 days.
  • Vaginitis caused by intravaginal devices starts 2-3 days after implantation and resolves shortly after removal (usually the devices are left in place for 10 days).


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Wiersma K (2000) Successful treatment of vaginal occlusion in a mare. Can Vet J 41 (4), 320 PubMed.
  • Trotter G W & McKinnon A O (1988) Surgery for abnormal vulvar and perineal conformation in the mare. Vet Clin North Am Equine Pract (3), 389-405 PubMed.
  • Acland H M & Kenney R M (1983) Lesions of contagious equine metritis in mares. Vet Pathol 20 (3), 330-341 PubMed.

Other sources of information

  • Zent W W & Steiner J V (2011) Vaginal Examination. In: Equine Reproduction. 2nd edn. Eds: McKinnon A O, Squires E L, Vaala W E & Varner D D. Wiley-Blackwell. pp 1900-1903.
  • Frazer G S (2009) Postpartum complications in the mare. In: Current Therapy in Equine Medicine. Vol 6. Eds: Robinson & Sprayberry. pp 789-798.
  • Blanchard T L & Macpherson M L (2007) Postparturient Abnormalities. In: Current Therapy in Euine Reproduction. Eds: Samper J, Pycock J & McKinnon A. pp 465-474.
  • Miller C D (2007) Infectious and Neoplastic Conditions of the Vulva and Perineum. In: Current Therapy in Equine Reproduction. Eds: Samper J, Pycock J & McKinnon A. pp 161-165.
  • Story M (2007) Prefoaling and Postfoaling Complications. In: Current Therapy in Equine Reproduction. Eds: Samper J, Pycock J & McKinnon A. pp 458-464.