Always frequent questions for veterinarians: "How often do geldings or stallions need their sheaths cleaned?" "Do you have to clean them?" "Why do they need cleaning?" As with any question, there are multiple answers depending on the horse.
The sheath houses the penis and associated loose folds of skin that stretch out and expand when the horse either has an erection or “drops” the penis to urinate. The skin inside produces a thick secretion called smegma. Smegma helps to moisturize and protect the skin of the penis and inside of the sheath. Because the inside of the sheath is a dark, moist space that doesn’t get much air, this smegma has a fairly foul odor.
During the summer and fall this smell can really attract flies, which can be very aggravating to the horse and induce skin irritation and allergy on the belly around the sheath. Of even more concern is the "bean." The bean, as it has been named, is a mass of smegma that collects in a cavity that surrounds the end of the urethra (the urethra is the tube in the penis where the urine comes out). If this bean gets large enough, it can actually put enough pressure on the urethra to prevent urine flow. This can be life-threatening if not caught in time.
How do wild horses survive without sheath cleaning? Well, wild stallions (no geldings in the wild) are breeding multiple mares in their group, which naturally removes/cleans these secretions. Geldings obviously aren’t breeding mares, so they may need more cleaning. Every horse is different on the amount of smegma they produce and may vary in how clean they keep themselves. Not every horse always drops to urinate, so the urine really makes the inside of the sheath a mess.
Horses that need sheath cleaning may have swelling in the sheath area, discharge, or even discomfort. Some horses will stretch out to urinate, but the stream will be weak or not flow at all. These signs can be confused with signs of colic.
Some animals will let you check their sheaths without sedation, but it can be risky. A great time to check sheaths is during routine sedation for teeth floats or other veterinary procedures. Usually, the sedation will relax the muscles of the penis so that it will drop and a complete exam can be accomplished.
When cleaning the sheath, it is important to remember that the smegma is there for a purpose. It moisturizes and protects the penis and the inside of the sheath. If it is cleaned too much or with products that dry and irritate, there will be more problems than with no cleaning at all. There are commercial products that are made specifically for cleaning, such as Excalibur®; mineral oil works for breaking up the smegma as well. Never use surgical-type soaps or wound cleansers such as Betadine or Chlorhexadine. Warm water from a hose helps to remove both debris and soap.
Above all, be careful. There are many horses that allow their owners to check and clean the sheath, but it is very easy to get kicked while working under the horse's belly. Also, “beans” can be difficult and sometimes painful to remove.
Stallions are of special concern when it comes to sheath cleaning. Smegma can harbor bacteria and viruses that can be spread to the mare during breeding. Stallions that are used frequently for breeding are inspected and cleaned often when they are about to breed the mare.
Take-Home Messages Concerning Sheath Cleaning:
1) That yuck is there for a reason
2) Don’t clean too often
3) Be careful!
Ask your veterinarian to check your horse’s sheath during times the horse is sedated. They can show you how to clean it and if it even needs cleaning at all.
