For the Nutritional Management of Pets with Urinary Tract Disease Associated with Struvite in Dogs Urinary tract disease is associated with the build-up of crystals and stones in the urinary tract that can cause painful and bloody urination and potential blockage in your dog. One type of crystal that forms in a dog's urinary tract is called struvite. Prescription Diet c/d was formulated specifically to provide nutritional management of dogs with struvite-related urinary tract disease. Struvite forms in response to urine saturated with magnesium, ammonium and phosphorus, as well as an alkaline (basic) urinary pH. ONLY AVAILABLE IN AUSTRALIA - QLD, NSW, VIC AND ACT