Merck Manual

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Pet Owner Version

Vulvitis and Vaginitis in Horses


Robert O. Gilbert

, BVSc, MMedVet, DACT, MRCVS, Reproductive Medicine, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University

Reviewed/Revised Sep 2019 | Modified Oct 2022

Vulvitis (inflammation of the vulva) and vaginitis (inflammation of the vagina) can develop due to difficult labor, chronic contamination of the reproductive tract due to poor conformation, sexually transmitted diseases, or mating. Bruises and hematomas (a pool of blood under the surface of the skin) of the vagina may be found in mares following delivery of a foal. Severe inflammation of the vulva and vagina, including local tissue death, may also occur. The signs of severe inflammation can include an arched back, elevated tail, poor appetite, straining, swelling of the vulva, and a foul-smelling, watery discharge. Signs begin 1 to 4 days after birth and last for 2 to 4 weeks. In most cases, supportive care and treatment with antibiotics is sufficient.

Dourine Dourine Blood parasites are organisms that live in the blood of their animal hosts. These parasites can range from single-celled protozoa to more complex bacteria and rickettsiae. The method of transmission... read more is a sexually transmitted disease of horses caused by the protozoan parasite, Trypanosoma equiperdum. Early signs of the disease include swelling of the vagina and vulva. Dourine occurs primarily in the Mediterranean coast of Africa, the Middle East, southern Africa, and South America.

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