Swollen Sheath in horses.

The sheath is the tube of concertina like skin that covers and protects a male horse’s penis. It can become swollen for a number of reasons. The most prevalent in my experience being the aftermath of castration.

Other causes include:

(1) Dirt, skin and oils can build up to form smegma - a sebaceous secretion that accumulates in the folds of the sheath. Over time, large “beans” can form and promote the carriage of Taylorella Equigenitalis (bacteria). In stallions, this can lead to Contagious Equine Metritis (venereal infection).

(2) Injury, resulting in (a) a lesion leading to infection, or (b) a hematoma.

(3) An infected bite from flies or bugs.

(4) Mud Rash.

(5) An allergic reaction to soap used to clean the sheath.

Getting back to castration, post-operative bleeding into the sheath is a common complication, as it is normal for a small amount of blood to drip from the incision site. However, excessive swelling indicates a problem, usually infection.

Castration operations have to heal from the inside out. If the outside skin seals over, a pocket of blood and serum can form, and the area usually becomes infected. The vet will generally re-open the incision site and administer a course of antibiotics.

Treatment:

(1) Smegma - Cleaning the sheath. Although not the nicest of jobs, it is necessary, and should be performed every six months. Here is a quick “how to”:

Wear thin latex gloves.
If it is the first time for the horse, have someone hold him, or if tied up, consider sedation. In fact, unless you are very sure of your horse’s reaction, and confident in your ability to do this yourself, ask your vet to do it for you.
Start by gently wetting the sheath and penis.
Use petroleum jelly to lubricate your hands, the sheath, and penis.
Carefully insert your hand into the sheath.
The smegma will break away and stick to your hand.
Remove at intervals and wash off in warm water.
Work your way up the sheath to the penis.
Remove smegma from around the penis.
Check for “beans”. If detected, gently roll out.
Rinse off the sheath - if you used soap, make sure you thoroughly rinse it off.

(2) Injury. An anti-inflammatory, as well as an antibiotic if infected.

(3) An antibiotic, and possibly antihistamine

(4) Daily cleaning, and an antibiotic cream.

(5) For a start, only use mild soap, but if it happens a topical cream if it does not clear up by itself.

In concluding, I must state that there is not universal agreement on the benefits of regular cleaning of the sheath. Some feel that it will “self clean.” However, all agree regularly handling to detect any abnormalities is a good idea.