Prevent CEM, Other Infectious Diseases Through Strict Hygiene

Strict hygiene guidelines should be followed whenever handling breeding mares or stallions to prevent reproductive infectious diseases, including contagious equine metritis (CEM).

CEM is spread between horses primarily by breeding, either by natural service or artificial insemination (AI). Grooms, handlers, and breeding technicians or veterinary personnel can also spread the disease if good hygiene is not practiced when working with either breeding mares or stallions. The current CEM outbreak in the United States underscores the need for careful hygienic procedures when breeding horses.

The following basic recommendations can assist in preventing the spread of CEM and other reproductive infectious diseases:

  • Use disposable examination gloves when working with the genitalia of breeding mares, foaling mares, tease stallions, or breeding stallions.
  • Change gloves between each and every animal.
  • Use alcohol based hand sanitizers or wash hands with soap and water between each animal if disposable gloves are not available.
  • Use disposable supplies whenever possible and discard between each horse. This includes: exam gloves, rectal gloves, vaginal speculums, tails wraps, practical cotton for washing, and all AI supplies, etc.
  • Disinfect or sterilize (with steam or gas) all non-disposable equipment between animals such as Bivona tubes, uterine lavage systems, embryo transfer collections units, AI phantom/dummy, surgical instruments, wash cloths, reusable tail wraps, etc.
  • Ultrasound probes should be covered with an equine rectal sleeve. Any equipment that cannot be washed or autoclaved/sterilized should be thoroughly cleaned and disinfected with an antiseptic or alcohol.
  • Use disposable plastic garbage bags to line any buckets used for washing or cleaning the genitalia of either mares or stallions. Change between horses and discard used liners in appropriate garbage containers.
  • Gloves should be used for post-foaling examinations of mares, placenta, and aborted fetuses. Keep placentas and aborted fetuses away from other horses, domestic animals, and wildlife.

If you have any concerns about any reproductive disease in your horse(s) you should contact your veterinarian. CEM cases or suspect cases should be reported to the USDA or your state animal health officials.  

For more information regarding contagious equine metritis, see the following fact sheets:

By Linda Mittel, DVM, Animal Health Diagnostic Center, College of Veterinary Medicine, Cornell University

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