Equine Coital Exanthema: Genital Sores, Breeding Rest and Biosecurity
In diesem Artikel
By Dr Duncan Houston
Small sores around a mare’s vulva or a stallion’s penis can disrupt an entire breeding programme. Pain is one concern; passing an infection to other horses is another.
Equine coital exanthema is often a local, self-limiting disease, but calling it mild should not imply that breeding can safely continue.
Quick Answer
Equine coital exanthema is a contagious disease caused by equine herpesvirus 3, or EHV-3, that produces genital nodules, blisters and ulcers. Stop breeding and contact your vet if suspicious lesions appear. Separate affected horses and equipment, and resume breeding only after veterinary assessment confirms an appropriate plan.
What does EHV-3 cause?
Lesions may begin as small red nodules and progress to shallow painful sores. They can occur on the vulva, surrounding skin, penis or prepuce. A stallion may become reluctant to serve because it hurts.
The MSD equine coital exanthema reference distinguishes this condition from EHV-1-associated disease. EHV-3 is not the usual equine herpesvirus responsible for abortion outbreaks or neurological disease.
Uncomplicated lesions mainly affect surface tissues. Secondary bacterial infection can worsen swelling, pain and discharge. Pale scars may remain after healing, but a scar alone does not prove an active infection.
How does it spread?
Direct contact during breeding is a major route. Contaminated hands, gloves or reproductive equipment can also transfer infection. A horse does not have to be actively breeding to encounter contaminated equipment.
As with other herpesviruses, latency and reactivation complicate control. The review of EHV-3 treatment and prevention discusses these limitations. Do not assume that infection is possible only when obvious sores are visible.
What level of action is needed?
| Finding | Action |
|---|---|
| Old pale scars with no current symptoms | Discuss history and breeding risk with the veterinarian. |
| New nodules, blisters or genital ulcers | Stop breeding, separate equipment and arrange prompt assessment. |
| Severe swelling, fever, inability to urinate or major pain | Urgent veterinary examination. |
What else might cause genital sores?
Trauma, contact irritation, bacterial disease, parasitic lesions and tumours can resemble aspects of ECE. Discharge can also arise from a different reproductive disorder. A picture cannot reliably distinguish these causes or establish breeding clearance.
Your vet examines the lesions and may collect swabs for PCR or other testing. Relevant history includes recent coverings, semen collection, reproductive examinations, shared equipment and contact with affected horses. Testing plans should be matched to lesion stage and laboratory advice.
When is this an emergency?
Call urgently if the horse cannot urinate, has severe genital swelling, becomes feverish or is markedly painful or depressed. These findings may indicate complications or a different problem. Do not force the penis out for inspection or attempt painful restraint without professional help.
What should you do next?
- Suspend natural covering and discuss any semen collection programme with the vet.
- Identify and record recent breeding and examination contacts.
- Separate affected animals, gloves, cleaning materials and equipment.
- Arrange examination and testing before applying products that may obscure lesions.
- Follow the prescribed hygiene, pain-relief and recheck plan.
Gentle local care and sexual rest are central to uncomplicated cases. Antibiotics may be appropriate for secondary bacterial infection, but do not eliminate the virus. Antiviral use requires veterinary judgement; it is not a routine home treatment.
Healing often occurs over a period of weeks, but a fixed calendar date is not clearance. Residual soreness, active lesions, contact risk and the breeding operation’s circumstances all matter.
Common mistakes
- Continuing to breed because the sores seem small.
- Reusing gloves or inadequately cleaned equipment between horses.
- Assuming antibiotics make a viral infection non-contagious.
- Relying on a photograph to certify healing.
- Confusing EHV-3 with other equine herpesvirus syndromes.
Prevention in the breeding shed
Inspect breeding animals routinely and stop when new lesions are found. Use fresh gloves and appropriate cleaning and disinfection between horses. Keep clear contact records and establish a plan for suspected cases before the breeding season begins.
Artificial insemination does not remove the need for hygiene and clinical assessment. Work with the reproductive veterinarian on collection and handling procedures rather than assuming a recovered donor poses no future risk.
Frequently asked questions
Will ECE permanently reduce fertility?
Uncomplicated infection usually does not cause lasting infertility, but pain and lesions interrupt breeding and complications need assessment.
Can non-breeding horses catch it?
Yes, indirect transfer through contaminated equipment is possible.
Can it recur?
Herpesvirus latency and reactivation mean recurrence is possible.
When can breeding restart?
After veterinary review of healing and the operation’s infection-control plan, not simply after a preset number of days.
Prompt recognition, breeding rest and careful hygiene protect both the affected horse and the wider breeding group.
For help understanding your horse’s care and preparing questions for your veterinarian, visit ASK A VET™. Urgent signs need an equine veterinarian in person.
