Learn about possible causes of dandruff in horses from the American Association of Equine Practitioners.
I own a 16-year-old mare who has had continuous brown/black dandruff (more like grains of sand) on her chest and girth areas. What is this, and how can it be controlled?
Based on your brief description, it sounds like your mare may have seborrhea or excessive scaling of the skin.
The following two paragraphs from a May 1, 2004, article at The Horse.com, Skin Problems in Horses: The Creeping Crud, written by Toby Raymond, provides an excellent description of this condition.
Seborrhea – Horses with sensitive skin, such as Thoroughbreds and Arabians, are more prone to this complaint than other breeds; however, seborrhea (skin discharge) can develop in any horse as a secondary condition to skin infection or allergy, or it could be a signal of poor overall health. Seborrhea takes two forms, either dry or oily. Dry seborrhea exhibits dry, flaky scales that look similar to dandruff and is found in the mane or tail. Thick, viscous crusts usually affecting the elbows or hocks are signs of oily seborrhea.
Wash the area with a sulfur-based shampoo once or twice a week to manage dry seborrhea, although recurrences are common. For oily seborrhea, depending on the severity of the case, wash the area at least twice a week using a drying shampoo (that contains tar or benzoyl peroxide, for instance), followed by a protective ointment to soften the crusts.
Adding corn oil or fatty-acid supplements to the feed will help improve dry skin. Also, maintain a regular grooming schedule to remove dirt and sweat. A soft curry comb can stimulate the skin to produce naturally occurring oils, which also might help control future outbreaks.
There are a number of antiseborrheic shampoos on the market, such as Allergroom by Virbac. I would recommend bathing your mare once or twice a week with an antiseborrheic shampoo. If the condition does not resolve, have your veterinarian examine your mare and determine if a different treatment may be needed or if the addition of supplements to her feed are recommended.
Dr. Etta Bradecamp