Struvite bladder stones are a form of canine urolithiasis. They develop most commonly after a staphylococcal urinary tract infection and consist of magnesium, ammonium and phosphate. The presence of stones is more common in certain breeds of dog. Eighty-five percent of canine patients are female, and stones recur in between 20 and 50 percent of patients. These facts make a predisposition to struvite stones easier to predict, and dogs at risk can avoid contracting stones or the urinary infection that causes them by following a preventative diet.
Drinking enough water is the single most important factor for avoiding the development of struvite bladder stones. Adequate water intake helps to dilute the urine and encourages frequent urination, which decreases the concentration of potential stone-forming minerals in the dog’s urine, according to a paper Dennis J. Chew delivered at the 2004 Small Animal Proceedings Symposium of the American College of Veterinary Surgeons. Pet owners can encourage dogs to drink more water by adding broth or other flavor enhancers to water.
Certain commercial pet food manufacturers have formulated preventative diets. They include Hill’s Prescription Diet Canine s/d brand or Royal Canin’s Urinary SO diet. These diets are called calculolytic diets and have very high fat and salt content, and should not be given to dogs with heart diseases, hypertension, any history of pancreatitis, or kidney deficiencies. The diets have restricted quantities of protein, phosphate and magnesium, and the additional salt is designed to increase the dog’s thirst. The Hill's food comes in the form of a soft, wet canned food, while the Royal Canin food comes in both canned formulation and kibble.
A homemade diet is one means of ensuring that the dog at risk of struvite bladder stones receives additional salt, which will result in her drinking more water. An easily digestible, low-fiber diet ensures that fluids are not lost through the intestine and should contain a high percentage of foods low in purine. A sample homemade diet low in purine would consist of 3 cups of cooked rice, two large hard-boiled eggs or half a tin of tuna, and 1 tablespoon of fish oil, stirred together.
Natural supplements that are beneficial preventative measures include cranberry capsules and vitamin C. Cranberry helps prevent bacteria from adhering to the tissue lining the urinary tract and bladder, and is available as juice or in concentrated capsule form. Cranberry is more effective if the patient receives it two or three times during the day, instead of in one dose. Vitamin C makes the urine more acidic, which helps to prevent the formation of stones. Also, veterinarians use probiotics extensively to treat bacterial infections. Probiotic supplements made especially for dogs are available.