The appearance of a horse’s tail, both at rest and during exercise, can tell us much about his general health and well-being. The tail should hang straight down and be carried in a relaxed manner. When viewed from behind, it should swing gently from side to side as the horse moves. The height of the tail carriage depends on an individual horse’s croup conformation and breed. For instance, a Morgan may naturally carry his tail higher than a Thoroughbred.
There are many reasons that a horse might hold his tail crooked or off to one side. As an equine veterinarian certified in spinal manipulation (chiropractic), I am often called in to assess a horse for abnormal tail carriage. One such cause is when there is a restriction (loss of motion in a joint and/or surrounding soft tissues) of the sacrum. The sacrum is roughly triangular in shape and is made up of five fused vertebrae, the last of which articulates with the first tail vertebrae. The cranial (front) part of the sacrum has seven articular surfaces, two being the sacroiliac joint, which is a commonly affected area in the dressage horse. The sacral apex (the part nearest the tail) can be restricted either to the left or to the right, and oftentimes this will cause the tail to point or move more in that direction. If this is the case, a manipulation, or “adjustment,” will often restore normal movement to the tail.
In some cases, the tail may have been fractured in the past or sustained other trauma leading to nerve damage. These tails may lack normal tone and movement, seeming floppy or overly still while the horse is working.
Some horses have a very active tail during exercise, swishing excessively, especially while being ridden. While this may be normal for some horses, I recommend having your horse evaluated by a veterinarian to rule out common causes for this behavior. Tail-swishing indicates tension in the horse, often from back pain or other orthopedic issues. Checking saddle fit and back health is a good place to start. Another common cause of tension under saddle is equine gastric ulcer syndrome.
The appearance of the tail itself can give us information about the general health of the rest of the horse. The tail should be full and lustrous with hair growing up to the base or top of the tail. It is common, especially in the summer, to see evidence of tail-rubbing, such as broken hair, bald patches and even skin lesions. There are many possible causes for this, such as internal and external parasites, allergies and pain.
Pinworms (Oxyuris equi) are a common cause of tail-rubbing and, unfortunately, due to increasing resistance to anthelmintics (dewormers), they are being seen more commonly and can be challenging to treat. The adult pinworms live in the rectum and deposit eggs around the horse’s anus. The eggs are surrounded by a yellow/white substance, which can often be seen around the anus, and causes extreme itching. Pinworm eggs are not typically identified with a standard fecal egg count test, such as the one used to assess for other gastrointestinal parasites. However, your veterinarian can apply clear tape to the skin around the anus to collect the eggs and then examine the tape under the microscope to find the eggs and make a diagnosis. Once pinworms have made your horse their home, it takes treatment not only of the horse, but also extensive decontamination of the environment to be rid of them.
Ticks are active during much of the year and will also cause a horse to rub his tail. Due to the high prevalence of Lyme disease and anaplasmosis, it is a good habit to check your horse daily for ticks.
Another cause of tail-rubbing is culicoides hypersensitivity, or “sweet itch.” Some horses develop a severe allergy to the saliva of these small biting flies and will rub their mane, tail and abdomen. This disease often progresses with age and, in some cases, the horse will rub until these areas are raw. Management involves treating the itch, treating any secondary bacterial infections and limiting contact of the horse with the flies using specially designed blankets, fans, insect repellents and avoiding turnout at dusk and dawn when the insects are most active.
Sometimes I am asked to evaluate a horse for tail-rubbing or sitting on water buckets when there is no evidence of parasites or history of allergies. In some cases, these horses have back pain, and leaning on the wall or their buckets gives them relief.
Finally, if you own a gray horse, the tail may be the first place you spot melanomas. Melanoma is a type of skin cancer, which in the horse tends to be benign in most cases.
Your horse’s tail can be a barometer for many different issues going on in the body. Whether you notice sudden, intense itching, a change in carriage or excessive swishing during riding, it is a good idea to have a conversation with your veterinarian as your horse is likely trying to tell you something.
Megan Graham, BVetMed, graduated from the Royal Veterinary College in London, England, in 2008, became certified in acupuncture through the Chi Institute in 2015 and completed her certification in spinal manipulation (chiropractic) with the Integrative Veterinary Medical Institute in 2016. A USDF bronze and silver medalist, she has been a dressage enthusiast since the age of 6. She works exclusively as an equine veterinarian, splitting her time between Ocean State Equine Associates in North Scituate, Rhode Island, and her own practice, Graham Equine Complementary Medicine, based out of Plymouth, Massachusetts.