What Causes a Thin Mane and Tail?

An owner is frustrated by her young Appaloosa show gelding’s persistent hair loss.

AM. SHOPE, Michigan

horse with alopecia (hair loss) or abnormal hair growth should be examined by a veterinarian, as effective treatment requires determining the underlying cause. Alopecia in horses has various causes, many of them as- sociated with pruritis (itching). Stressful events (systemic illness, high fever, surgery) can also cause hair follicles to halt in a specific growing phase, resulting in widespread alopecia or hair abnormalities and breakage. New hair growth begins one to three months after the event.

Another cause of alopecia is follicular dysplasia. This condition causes hair-follicle abnormalities, including atypically formed hair shafts that easily break, or poor hair growth overall. One example of follicular dysplasia—and one that may be related to your gelding’s case—is mane and tail dystrophy, where hair loss is restricted to these regions and the hairs are dull, short, and brittle. This syndrome (seen as early as at birth, or recognized in adulthood) is most commonly reported in Appaloosa and Curly horses. It’s believed to be related to an autoimmune disorder called alopecia areata. The cause of alopecia areata in horses is similar to that seen in other species, including humans, dogs, cats, cattle, mice, and poultry. Autoantibodies (the body’s own immune-system antibodies attacking self-proteins) are directed against antigens of growing hair follicles. The hair follicles go into their resting phase (see box), resulting in hair loss, then the follicles become abnormal.

The disease has a suspected genetic or heritable predisposition and, as

mentioned, Appaloosas are more commonly affected. Some cases worsen in the spring/summer and improve in the winter. Sometimes alopecia goes into remission six months to two years after onset; other times the disease persists.

Under the direction of your veterinarian, treatments for alopecia areata can include medications, such as corticosteroids, that suppress the im- mune system. Such treatments result in variable success.

To encourage hair growth in general, work with your vet or an equine nutritionist to ensure that your gelding’s diet is optimal, with adequate vitamins and minerals. Supplements containing biotin, methionine, zinc, and/or copper can enhance the growth of keratinized tissues, including hair and hooves. More on tails: “Cure That Tail Rubbing.”