Some horse owners feel that it is a good idea to ‘wash’ a gelding’s sheath and penis on a regular basis. The theory is that a gelded horse may not let the penis down out of the sheath as regularly as a stallion may, leading to bacterial overgrowth from poor hygiene. However, this has not been shown to be the case. Although regular cleaning may seem worthwhile in terms of overall hygiene, it can in fact create problems for the horse. A certain amount of “smegma” or discharge from the penis is normal and does not necessarily indicate the need for washing.
Why may sheath washing be a bad idea?
The problem arises from the fact that a horse’s penis normally contains a certain amount of commensal bacteria (good bugs) and oils which keep it healthy. Overly frequent washing strips away the oils on the skin whilst the bacteria are removed by antiseptic shampoos. The lack of oils on the skin of the penis means that the skin will become dry and cracked whilst pathogenic (disease-causing) bacteria are able to invade not only the skin but also the cracks that are formed.
These infections can be very difficult to treat and can become prolonged. Therefore, if your horse appears to have a healthy penis and sheath, there is almost certainly no need to wash it at all. Some horses can produce large amounts of smegma or may need their sheath cleaned prior to a show and may benefit from occasional flushing with a mild saline solution.
In extreme cases some horses have developed smegma stones that need to be removed manually. In this instance it is best to seek the advice of your veterinary surgeon who can advise on an appropriate washing regime.