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Contagious Equine Metritis

Welcome to Cornell University’s CEM Quarantine Facility

About Our Facility

Cornell University’s CEM Quarantine facility is located on Snyder Hill Rd, Ithaca, NY, in close proximity to Cornell University Animal Hospital.

We have 18 stalls available for CEM horses.  Our stalls are approximately 12ft x 17ft and are constructed of 2 x 6 tongue-in-groove pine.  Each stall has a stall mat on the floor to increase comfort and safety.  We also have indoor and outdoor turn-out areas.  The indoor turn-out area is 40ft x 60ft and the outside paddocks are even larger. Horses are turned out daily in the outdoor paddock and during inclement weather horses are turned out in the indoor arena.  

CEM Quarantine Facility

What is Contagious equine metritis (CEM)? 

USDA APHIS VS defines CEM as a transmissible, exotic, venereal disease of horses caused by the bacterium Taylorella equigenitalis.  CEM is a serious disease because it is highly contagious. When coupled with the fact that mares can be bred only during certain seasons, CEM can have a devastating effect on equine reproductive efficiency.  Should CEM become established in the United States, the horse industry would suffer great economic losses.

How is CEM transmitted?

CEM is commonly transmitted directly during sexual intercourse between undetected CEM positive breeding mares and stallions. Transmission may also occur indirectly by artificial insemination or contact with fomites, such as contaminated hands or instruments. Outbreaks usually occur at breeding facilities following international horse shipments. Undetected carrier mares and stallions are the source of infection for acute outbreaks of the disease. During the breeding season, a carrier stallion may infect several mares before the disease is suspected or diagnosed.

Can it be treated?

The mare cannot be successfully treated until the CEM bacteria clear from the uterus, a process that may take several months. The external genitalia of the mare and stallion can be treated with disinfectants and antibiotics. Once daily for 5 consecutive days, the external genitalia should be gently scrubbed with 2-percent chlorhexidine in a mild detergent solution and rinsed with a warm saline solution. The external genitalia should then be coated with an antibiotic ointment, such as nitrofurazone. Due to the effectiveness of this treatment, surgical removal of the clitoral sinuses is rarely required.

Can CEM be prevented and controlled?

Quarantine and test all imported fillies, mares, and stallions of foreign origin, and mares and stallions not previously bred in the United States that are older than 731 days (2 years).

  • Quarantine and test the first three mares bred to a stallion of foreign origin.
  • Quarantine all suspects until all test results are negative.
  • Avoid breeding any CEM-positive horses until they have been successfully treated and certified CEM negative.
  • Maintain strict hygiene when handling mares and stallions (e.g., use disposable gloves, change gloves between horses, and thoroughly clean and disinfect instruments).

For more information about CEM please visit:

Technical Information