Urinary Stones

Does your horse appear to have difficulty when urinating? Does your horse stretch out to urinate and remain in the pose for a prolonged period of time? Have you found blood in your horse’s urine or periodic leaking of urine from your horse? Has your horse exhibited ongoing colic episodes and sweating or have there been changes in your horse’s gait? 

If “yes” to any of these questions, your horse could be suffering from urinary stones. 

Urinary stones are formed in horses when concentrations of minerals, primarily calcium, group together in the urine to form crystals, which can increase in size. Urinary stones are most commonly found in the bladder, known as cystoliths; but can also be found in the kidneys, referred to as nephroliths; and in the uretha, called urethroliths. These stones can obstruct urine, which can cause kidney failure and even death in horses if left untreated. 

While a clear cause of urinary stones has not been identified, it is speculated that high levels of minerals in feed and water may lead to urinary stone development in horses. Other causes may include bacterial infection in the urinary tract; medications such as phenylbutazone and flunixin, which can cause kidney damage over time; or a disproportionate amount of calcium and mucous in the urinary tract. Additionally, a horse’s urine is quite basic (high pH) naturally, which can support the formation of stones. Male horses are more likely to develop urinary stones than female horses, and are seen more often in adult horses than young horses. 

Surgical removal is the most frequent method that an equine veterinarian will use to treat urinary stones. The type of surgery will depend on the location of the stones, the size of the stones, and the gender of the horse. Your equine veterinarian will generally begin by conducting an examination of the bladder through the rectum of the horse. Endoscopy and ultrasound may be used to determine the number, size, and location of the stones. A cystoscopy may be used to determine if there is free flow of urine from the kidneys to the bladder, if there is a urine blockage, or if kidney disease is present. 

Consult with Atlantic Equine Services to schedule an evaluation if you think your horse may be experiencing symptoms of urinary stones.

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