Urinary calculi formed by the precipitation of salts from the urine occur especially in cattle, sheep, dogs and horses. The presence of calculi in the urinary tract may cause no apparent discomfort to the animal, or they may cause serious symptoms and result in death due to the obstruction of the flow of urine. They usually occur primarily in the wider parts of the urinary apparatus, either in the renal pelvis, possibly in the straight urinary tubes, or in the bladder and may later be carried to other portions of the urinary passages.