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Contagious Equine Metritis (CEM)


Contagious equine metritis is a sexually transmitted disease caused by the bacterium Taylorella equigenitalis.  Unless you are importing horses or semen from other countries, Contagious equine metritis (CEM) shouldn’t be a concern. CEM does not exist in the United States, but preventing its entry is important and requires some stringent rules to be enforced.  All stallions and mares of breeding age that are to be imported from a country with CEM present must undergo rigorous testing and quarantine procedures prior to mixing with any other animals. As CEM is sexually transmitted, immature animals and geldings are not required to undergo these procedures.

Recently infected mares will develop uterine inflammation (metritis) which leads to reduced conception rates and a vaginal discharge for a short time. Infected stallions and chronically infected mares have no visible clinical signs. CEM is so contagious that almost every mare mated with an infected stallion will contract the disease and semen can be a source of infection, thus AI is not without risk. CEM is difficult to detect and identify due to the healthy appearance of stallions and thus, rigorous testing is essential to diagnose the disease.

If you are importing a sexually mature horse from another country, please contact the Florida Department of Agriculture and Consumer Services, Division of Animal Industry to obtain an application of the Owner’s Agreement for Quarantine for CEM. International shipping agents or the Department will also have a list of approved quarantine facilities within the state of Florida; these facilities will provide a qualified, licensed, and federally accredited veterinarian to perform all required procedures and can advise you about the costs.

This column is sponsored by Polk Equine.

BIO: Dr. Katie Hennessy graduated from the University of Illinois College of Veterinary Medicine in 2008 with a degree in large animal health and equine medicine.  She completed an advanced internship at The Equine Medical Center of Ocala and is currently the owner and practicing veterinarian at Polk Equine. Her expertise ranges from small and exotic creatures to large animals, specializing in equine medicine.