Urinary Calculi

 A hard mass of mineral salts in the urinary tract caused by dietary imbalance; seen in male animals it causes blockage of the penis and subsequent death due to renal failure if not treated. The disease is most common in castrated males on a high cereal diet. The signs are restlessness, straining to urinate, pawing the ground, constantly looking at its own abdomen, vocal signs of pain.
Treatment involves surgery to remove the blocked penis and create a new opening for the urethra which is the tube that carries urine from the bladder to the outside.