Common causes for tail rubbing in horses
Seasonal tail rubbing is often a result of a hypersensitivity response to certain insects—in particular Culicoides gnats—which inject salivary antigens (proteins) in the insect bite. Another less obvious cause of tail rubbing is due to a collection of debris and smegma in a male horse’s sheath that causes him to rub his tail in response to localized itch and discomfort in the sheath area, which he can’t reach. Pinworms (Oxyuris equi) are also known to irritate the anus and stimulate tail rubbing.
Diagnosing the cause of tail rubbing in horses
Culicoides hypersensitivity in horses is also referred to as “sweet itch.” In severe or advanced cases, itching is not just confined to the tail, but the horse also will also rub his mane, neck, and chest in response to the systemic reaction generated by gnat bites. At times, tail rubbing goes beyond just broken tail hairs; the tail may be completely denuded of hair, with self-inflicted trauma sufficient to create bleeding areas and a “rat-tail” appearance.
How to treat tail rubbing
For a dirty sheath, cleaning helps to resolve the problem. Parasite control eliminates pinworms (Oxyuris equi) as a source of tail rubbing. Culicoides gnats require free-standing water to propagate, therefore avoid stabling a sensitive horse near ponds, marshes, or lakes. The ideal solution is to move the horse away from habitats that are known as gnat breeding grounds. Besides controlling insects, itch control may be addressed with topical oatmeal therapy containing pramoxine or steroids, by feeding fatty acids, and through medication with anti-histamines and/or systemic steroids during insect seasonal times of the year.
Preventing tail rubbing
Gnats tend to feed at dusk and dawn, so these are opportune times to stall a horse, and use fans to counter poor-flying gnats. Fine mesh screens (smaller than 32 by 32 mesh) over stall openings keep gnats out. Insecticidal sprays should be used on a regular basis or implement time-operated spray mist insecticide delivery mechanisms. Fly sheets and fly masks create a physical barrier so insects cannot feed as easily on the horse. Once- or twice-annual sheath cleaning keeps that are free of debris, and an appropriate deworming program eliminates pinworms as a source of irritation.