Normally, horses carry their tails parallel to the spine. Wry tail describes a horse carrying his tail to one side. While it's a genetic trait in some breeds, in other horses it might indicate soundness issues. A wry tail varies from slightly off to extremely crooked. The tail carriage can change over time, with the crookedness becoming more or less pronounced. If your horse develops a consistent wry tail, call your vet for an examination.
While many Arabians and part-bred Arabians, such as the National Show Horse, sport a wry tail, it's not considered a desirable trait in the breed standard. In conformation classes, it will earn faults. However, a horse with Arabian ancestry carrying a wry tail doesn't necessarily indicate any back or soundness problems. That might not be true of equines with little or no Arabian blood.
Since equine backs carry a rider's weight, they're quite subject to stress and strain. While some symptoms of equine back issues are subtle, others are obvious. A sudden onset of wry tail carriage might indicate back pain in your horse, even if he doesn't appear to be hurting. However, back pain symptoms often show up in other parts of the horse's anatomy, including toe dragging in the rear hooves and high head and neck carriage. Your vet can watch your horse move and detect subtle signs that your horse is hurting. Of course, don't ignore obvious signs like pain when saddled or even rearing when mounted.
Suddenly carrying the tail aside can indicate that the area under the horse's tail is irritated. Check the underside of the tailbone and anal area for ticks or other bug bites, or any other kind of inflammation.
Sudden wry tail carriage also occurs due to injury. Carrying his tail in that manner may allow it to act as brace when moving. If you know your horse has fallen or been cast in his stall, you should be on the lookout for any injuries. Horses turned out on pasture might fall and slip without anyone seeing them. If your horse comes in from the field carrying his tail crooked, suspect a fall or perhaps a kick from another horse.
Horses often "flag" their tails and carry them sideways when stressed or excited. You'll notice other behaviors as well, such as snorting or running. Once the horse calms down, the tail goes down as well.
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