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Equine Health Resource

Endometritis, Chronic

Chronic inflammation in the mare’s uterus is a common cause of infertility and abortion in older mares. It usually results from a combination of factors related to the decreasing emptying function of the uterus as mares age, coupled with bacterial contamination resulting from worsening barrier function.

Uterine biopsy, culture and cytology characterize the severity of the problem.

Treatment revolves around improving barrier function (Caslicks operation), clearing infection and improving uterine defenses with medications and better emptying.


  • How severe is the change in the uterine lining based on the uterine biopsy?
  • Does the mare pool uterine fluid?
  • Does the mare have a problem with her cervix?
  • Does the mare have a problem with vulvar seal or conformation?
  • What is the likelihood based on the uterine biopsy score that the mare will carry a foal to term?
  • What can be done to improve the mare's fertility?

    Monitor mares with ultrasound pre and post-breeding. Treat uterine fluid accumulations. Some mares need Caslicks placement in order to prevent or treat this problem.

    Helpful Terms & Topics in HSVGWritten, Reviewed or Shared by Experts in Equine Health

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    Author: Doug Thal DVM Dipl. ABVP


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