What you see. The starting point for addressing any equine health related issue is your observation.


Drainage from Sheath


Drainage from the sheath is most commonly smegma, which is usually not a cause for concern. Smegma is a thick pasty material that is composed of mucus, debris and shed cells. Smegma tends to be similar in color to the sheath skin. In most geldings and stallions, it is dark, but it is often reddish in pink skinned horses. Some horses produce more smegma than others.

The existence of smegma does not mean that the sheath is infected. True bacterial infections of the sheath are rare without some underlying abnormal condition. Drainage from the sheath is also seen in horses with with tumors, abscesses and chronic infection and inflammatory conditions. In breeding stallions, excessive drainage of the sheath can indicate CEM, a reportable disease.

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your role


What To Do

Evaluate your horse's sheath and try to determine whether the drainage is a result of accumulation of smegma or another condition. Feel the end of the penis for a "bean" which is a hard accumulation of smegma. Remove it if it is easy to do so.

Pay particular attention to rectal temperature, attitude and appetite. Note any hair loss or evidence of trauma around the sheath. Look for swelling of the sheath and pain to the touch. Observe the pink skin for redness. Not any abnormal odors. Assess your horse's general health using the Whole Horse Exam (WHE) and share your findings and concerns with your vet.

What Not To Do

Do not use disinfectant soaps to clean the sheath. It can change the bacterial population, leading to more problems.

your vet's role

Vets typically tranquilize horses for sheath examination and cleaning. This drops the penis and provides much better visualization of the penis and sheath.

Periodic sheath cleaning, by a horse owner or especially a vet, encourages visual inspection of the penis and sheath. Problems such as tumors (that affect this region frequently) can therefore be diagnosed and treated early, improving prognosis and lessening treatment costs.
Questions Your Vet Might Ask:
  • Tell me more about the color, smell, and quantity of the drainage.
  • Do you notice any swelling of the sheath?
  • How old is the horse?
  • Do you notice a growth, mass or wound associated with the penis or sheath?
  • Is the horse a stallion or a gelding?
  • Does your horse drop his penis down when he urinates?
  • Do you notice any abnormalities of the penis or sheath?
  • Are you able to see or feel a bean or mass near the end of the penis?
  • Do you think the horse's attitude and appetite are normal?
  • Do you routinely clean the horse's sheath?
  • What are the results of the Whole Horse Exam (WHE)?

further reading & resources


Helpful Terms and Topics

Written, reviewed or shared by experts in equine health

Author: Doug Thal DVM Dipl. ABVP