Written by: Melissa McKee, DVM

It’s a dirty job, but somebody’s got to do it. Melissa McKee, DVM, explains how to clean a sheath and why it’s so important.

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Every gelding owner knows several times a year they have to roll up their sleeves and tackle one of the less appealing grooming duties that comes with ownership of a male horse… sheath cleaning. Although this is a chore, regular sheath cleaning is an important part of your horse’s health care and it is important that it is done properly and thoroughly.

The sheath is an enfolded pocket of skin on the underside of the belly, just in front of the hind legs, that provides protection and support for the penis. When the penis is dropped for urination or breeding, most of the lining of the sheath stretches out and becomes visible along the penile shaft, but when the penis is retracted, all of that skin becomes bunched up on the inside of the sheath, much like a rumpled sleeve when you pull your arm backwards out of a shirt.

This bunched up and folded skin secretes natural oils and sheds skin, which combines with sweat and dirt to form a sticky, foul smelling residue called smegma. If you run your finger just inside the opening of the sheath, you will feel greasy clumps of dirt trapped in these loose folds, and if you look at the penis when it is dropped, you can see these ridges of dirt and sheets of flaking skin along the shaft.

At the very tip of the penis lies the opening of the urethra and a structure called the urethral fossa. Urine flows from the bladder through the urethra and exits through this small aperture. The fossa is a blind-ended pouch that lies adjacent to the urethral opening, forming a natural trap for skin, oil and debris. This accumulation is referred to as a “bean” and can become large enough to obstruct the flow of urine and be quite painful for the horse.

Studies have demonstrated that accumulated smegma can predispose a gelding to an aggressive type of skin tumour called squamous cell carcinoma on the penis, and regular cleaning to reduce this build-up can have a protective effect against this invasive cancer. Squamous cell carcinoma causes red, irritated, ulcerated patches on the skin and sometimes will have a wart-like appearance. They often bleed easily and are tender to the touch. Early recognition of this problem is key to effective management, which can involve freezing the masses with liquid nitrogen, topical chemotherapeutic agents, oral medication, and surgical resection of the diseased skin or of the entire end of the penis. Left untreated, this type of tumour can be quite invasive and extend into local lymph nodes so it is well worth your time to check this area regularly.

How often should you clean a sheath?

Every horse is different. Some geldings are naturally very dirty and benefit from cleaning every few months, while others are fine with a thorough cleaning once a year and the occasional “polish.” Horses with unpigmented skin on the penis are more prone to squamous cell carcinoma and should at least be visually checked every couple of months, which you can easily do when the horse drops to urinate. Try to avoid too-frequent cleaning, as this can create a bacterial imbalance and allow more pathogenic species of bacteria and fungus to accumulate. In rare occasions, a chronic infection can occur, leading to a foul smelling discharge. In these cases, a skin swab should be submitted for culture and appropriate medical therapy instituted.

What do I need?

Sheath cleaning doesn’t require special equipment. Any mild skin or dish soap, such as Ivory, or a commercial preparation from the tack shop is appropriate, but no matter what you choose, you must rinse thoroughly because residues in this area are very irritating. For this reason I would avoid any “leave in” treatments because a painful blister can occur in sensitive horses. You can accomplish the task very effectively with the following supplies:

  • Mild soap
  • Dish or exam gloves (these are essential, or the odour will cling to your hands and it is nearly impossible to get this dirt out from under your nails)
  • Large (60cc) oral dose syringe or turkey baster
  • Disposable sponges or roll cotton
  • Clean warm water in two buckets
  •  Sedative/relaxant if required (only under veterinary supervision)

Safety First!

Many geldings are comfortable having their sheaths cleaned and tolerate gentle traction on the penis in order to exteriorize it for a thorough examination. Others are a little tense and can benefit from medication to reduce tension on the penile retractor muscles. This is why one of the best times to clean a sheath is right after the vet has sedated them for another procedure such as dental work. Some horses are just too shy and ticklish in this area to allow you get this job done safely, and in those situations you are better off asking your vet to do the cleaning.

With time and patience, many can become accustomed to being handled in this area, but never get into a wrestling match trying to extract the penis from the sheath because you can damage the muscles and nerve supply, not to mention the danger of being kicked by an angry or frightened horse! Remember that even with the quietest and best behaved horse you are in a very vulnerable position with your head near the hind feet. Always err on the side of safety.

What are the signs that my horse needs his sheath cleaned?

The most obvious sign is shreds of dirt and skin on the penis when it is dropped to urinate. If the “bean” at the tip of the urethra is very large, the horse may actually have trouble urinating or the act will appear painful. A foul smell or cheesy looking discharge is a clear indication it is time to clean, and both mares and geldings may start to tail rub if there is significant dirt accumulation in the sheath, udder and beneath the tail. Even if you don’t notice any of these obvious signs, it’s still a good idea to clean and inspect the sheath a few times a year. It’s a good idea to avoid sheath cleaning in extremely cold weather, especially of your horse needs a light tranquilizer to get the job done, which tends to leave them dropped and dangling for a while. Wet exposed flesh can freeze very quickly and significant frostbite damage can occur.

How to Clean a Sheath

Step 1. Using the sponge or cotton, dip it in the warm water and then insert your hand into the sheath and start to wet the area. Use only one of your buckets, and keep the second one clean for your rinsing. If your horse accepts it, you can use the turkey baster/syringe to squirt water into the sheath.

Step 2. Ideally, your horse will start to relax and his penis will drop down. Other more nervous horses may need some sedation to achieve this, or you can try to work “blind” (reaching inside the sheath), which is not ideal, but still moderately effective for most situations.

Step 3. Use a small amount of soap to help lubricate and loosen the greasy smegma. Remember that all the soap that goes in has to come out in the rinse, so start with a conservative amount.

Step 4. Work gently to clear the surface dirt and dead skin from the sheath and shaft of the penis. Sometimes the crusty material on the penis is still a bit adhered, so be careful when you pull this off.

Step 5. Time to extract the bean. Using a soapy finger (clipped nails please!), gently work it into the pocket that lies just above the urethral opening. If your horse tries to withdraw his penis, you can apply gentle traction on the shaft, but never get into a wrestling match because you can damage the retractor muscles.

Step 6. Once the bean is extracted, use your clean water and syringe or clean cotton/sponge to thoroughly rinse the entire area.

 

DON’T FORGET THE LADIES

While mares don’t have a dirty sheath to tackle, they do accumulate similar grime between the teats and around the vulva. This can lead to irritated skin, tail rubbing and vaginitis, so regular cleaning of these areas is essential for their comfort and well-being.

As with geldings, patience, mild soap and lots of warm water is the key to success. All of the safety considerations mentioned about geldings apply to mares too. Be particularly careful about water trickling down the hind legs, especially during fly season, as this is especially annoying and can cause the occasional kick.

Use a sponge and soap to gently loosen and clean away accumulated dirt around the vulva and udder, particularly in between the teats where a buildup of material can be quite irritating and is a common cause of tail rubbing. Again, be sure to rinse all residue off very thoroughly. Some mares are very touchy about these areas, so the emphasis here is again on safety!