Sheath washing – to wash, or not to wash!

Regular washing of a gelding or stallion’s sheath and penis is something that horse owners debate on a regular basis. The following information should make the decision “to wash, or not to wash” an easy one!

As a general rule there is no need to wash your horse’s sheath or penis on a regular basis.
The sheath and penis have a normal population of bacteria on their surface, the bacteria doesn’t cause disease and helps to maintain the health of the skin and prevent the possible invasion of unwanted bacteria. Therefore, routine washing can have a detrimental effect if the normal bacteria are washed away.
Some detergents are very strong and can wash away the natural oils on the skin causing dry penile skin which can crack and lead to irritation, damage, inflammation and infection. Washing with a strong detergent can remove the natural skin oils leading to dry, cracked skin where infection can set in.

A normal sheath and penis are naturally smooth, supple and oily, and produce naturally occurring secretions.
Normal things you may notice include secretions of the skin glands and dying skin cells on the penis and within the sheath, this is called smegma and is usually either black, grey or cream coloured; it is of a waxy consistency and has a greasy feel to it. Most horses produce very little smegma, but some can produce quite a lot which can be seen at the opening of the sheath and on the inside of the legs.
Any secretions or discharges other than smegma, especially if it smells unpleasant, could be a sign of infection. Common bacteria causing venereal (sexually transmitted) diseases include Klebsiella pneumoniaPseudomonas aeruginosa and Taylorella equigenitalis. The presence of any abnormal secretions or discharges should be investigated by a vet.

Horse smegma has been repeatedly proposed as an important factor causing penile cancer. This suggestion is based on one study in which equine smegma produced three different types of cancer (papillomas, squamous cell carcinomas and fibrosarcoma) at the site of injection in mice. A second study, which found that while infection with equine papilloma virus may be the initiator of the development of one type of penile cancer know as squamous cell carcinoma, smegma may also play a role.
In addition, there is the suggestion that smegma predisposes to genital cancer in man. Similarly, poor hygiene followed by chronic irritation and penile inflammation, has also been proposed to induce cancer formation. However, this does not constitute scientific proof that smegma causes penile cancer.

If your horse appears to have a healthy clean penis and sheath there is almost certainly no need to wash it at all.
If, however, your horse produces a lot of smegma, you may notice this at the opening of the sheath and on the inside of the legs; in these circumstances it would be sensible to occasionally wash the affected areas.
Where excess amounts of smegma are produced, it can form into bean shaped lumps with lodge themselves within the sheath and can cause irritation and discomfort for your horse. In these cases, your horse may be reluctant to release his penis when urinating; if this is true of your horse, washing can prevent these lumps from forming.

Never use antiseptics or detergents to wash your horse’s sheath as these will have a detrimental effect on the natural oils and normal bacteria in and around the sheath area.
Use warm water and a gentle, hypoallergenic soap. It is possible to purchase special ‘sheath cleaners’ which will be specially formulated to maintain the natural pH balance of the skin and will not affect the natural protective bacteria.
In cases where lumps of smegma have formed inside the sheath, a small amount of baby oil will help to loosen these. Be careful not to use an abrasive sponge or cloth; cotton wool or soft sterile swabs are more suitable options. It is also very important to make sure you rinse all the soap away to avoid irritation.