Thanks to your diligent grooming, your horse's tail looks long and luxurious. But when was the last time you peeked at the underside of his tailbone? This is an easy area to overlook during your daily grooming, but problems can develop there and worsen with time.
Ticks like to attach themselves to the tailbone, including the underside. Not only can they irritate the skin, but they may spread Lyme0 disease and other illnesses. Feel under the tail daily---especially in the fall when adult ticks are active---and carefully remove them by pulling their bodies straight off the skin.
Dry, flaky or waxy skin on the underside of the tail can be itchy and uncomfortable, leading to tail rubbing and hair loss. If the skin under your horse's tail looks irritated or even unusual, wash it with a gentle medicated shampoo and see if it improves. If not, call your veterinarian in for a specific diagnosis and treatment plan.
Older gray horses will often develop melanoma0 tumors on the underside of the tailbone. These firm, dark lumps may not cause the horse any trouble, but if they become large enough to interfere with defecating or they slough open and become infected, you may want to get them removed. Consult with your veterinarian when you first notice the tumors, so she can keep track of how fast they are growing and assess the risk posed by their location.