If your dog was diagnosed with struvite stones, you may be wondering what dietary foods for dogs with struvite crystals and stones are out there. Struvite stones are quite unique in their composition. Being composed of magnesium ammonium phosphate, struvite stones require a different treatment compared to other types of bladder stones in dogs. While there are various treatment options for bladder stones in dogs, the role of diet for dogs with struvite stones plays an important role and shouldn't be ignored.
Struvite Stones in Dogs
Among the different types of bladder stones in dogs, struvite stones are so far the most common. These stones are radiodense, meaning that they can be visualized on radiographs quite easily. Most likely, your vet diagnosed these stones in your dog after taking an x-ray or ultrasound.
How do stones form? Here's a little lesson in physiology. Normally urine contains waste products and these include mineral salts such as magnesium ammonium phosphate in the case of struvite stones.
In an ideal situation, these minerals should be dissolved in urine, but when things go wrong, they fail to dissolve and the urine ends up being oversaturated with crystallogenic substances (a medical state known as crystalluria), explains veterinarian Dr. Ines Di Giacomo.
When the crystals join together, stones are formed. Struvite stones are unable to pass through the dog's urinary system and therefore fail to get expelled when the dog urinates.
The Role of Urinary Tract Infections
Dogs who suffer from urinary tract infections are particularly predisposed to the formation of struvite stones. This is because bacteria like staphylococci areurease producing microbes. In dogs, the majority of struvite stones are indeed infection-induced. It may take a few days to a few weeks following the urinary tract infection with urease- producing microbes for struvite stones to form.
Because urinary tract infections are more likely to affect female dogs due to their anatomical features, they are more predisposed to struvite stones compared to male dogs. If we look at statistics, it is shown that 85 percent of dogs suffering from struvite stones are female, while males are only 15 percent.
Other predisposing factors are urine with a high pH, excess urine concentration, the administration of certain medications and certain types of diets.
The Importance of Water
Because excess urine concentration plays a role in the formation of struvite stones, it's important that dogs have always access to fresh, clean water. Increased water intake can help dilute urine and therefore reduce the concentration of minerals in the urine.
Sometimes dogs need to be enticed to drink more water and there are several smart ways to get dogs to start drinking more. A dog fountain may attract dogs, enticing them to drink more, or another option is to add to the dog's kibble some warm water or even some plain homemade chicken or beef broth (with no onion, garlic, salt or spices added). In the summer, dogs may be enticed to drink more by offering them ice cubes or frozen chicken stock to lick off.
On top of that, it's important that dogs are frequently let out to potty considering that dog urine concentrates when dogs do not urinate for some time. Dogs who are confined for a long time in the home while the owner works or well-potty trained dogs who are enclosed in a kennel are prone to developing urinary tract infections, and consequently, stones due to their concentrate urine.
Prescription Diets for Struvite Stones
Dogs prone to the formation of struvite stones have alkaline urine which makes crystals prone to forming and aggregating to form stones. It is therefore important to make the dog's urine more acidic to prevent their formation, explains veterinarian Dr. Fiona.
Struvite crystals can be dissolved with special veterinary prescription diets such as canned Hill's S/D.
Hill's S/D helps promote desirable pH levels in the urine and contains high-quality protein (in reduced amounts), low magnesium and phosphorous levels, sodium chloride (basically, salt to increase drinking) and healthy antioxidants. With the use of Hill's S/D, struvite crystals are clinically proven to dissolve in as little as two weeks, but can take to several months.
Another prescription diet meant for dogs suffering from struvite stones is Royal Canin Urinary S/O diet. This diet helps promote the dissolution of struvite, increases urine volume and has reduced levels of magnesium. It's important that once the stones are dissolved, that the dog is put on a diet that prevents them from re-forming.
Why are struvite diets by prescription only? There's a good reason. Such diets may be counterproductive in dogs suffering from certain medical conditions. For example, diets for struvite stones contain salt which can be dangerous for dogs suffering from heart failure and hypertension, while their richness in fats can cause a bout of pancreatitis in predisposed dogs.
"After dissolving the struvite stones, we want to prevent them coming back. There are also prescription diets for this. Hill's C/D diet is an "acidifying diet" which means it makes the urine more acidic to prevent stones from re-forming. "~Dr. Fiona, veterinarian
Treats for Dogs with Struvite Stones
For owners of dogs looking for healthy treats, Dr. Fiona suggests making S/D chews. Here are some directions on how to make them.
Simply remove the top and bottom off a can of S/D so that it comes out in a whole piece and then slice it into cookie shapes that are about half an inch thick. Next, pop them in the oven for 15 minutes baking at 350 degrees or until they are nice and crunchy. Let them cool down and then give them for your dog to enjoy.
Did you know? Because bacteria tend to leech out as the stones dissolve, it's important that dogs are given antibiotics during that time and that the dog's urine is routinely checked. Always consult with your vet when making changes to your dogs diet or giving supplements meant to dissolve stones.
"When dissolving struvite uroliths by medical protocols, antimicrobial drugs should be administered as long as the uroliths can be identified by survey radiography."~Carl A. Osborne, veterinary internal specialist.
Homemade Dog Struvite Stone Diet
While it's tempting to give a dog a homemade diet, it's important to recognize that homemade diets are at risk for not being nutritionally complete.
Veterinary nutritionists have been finding that an astounding number of diets formulated by dog owners were lacking essential nutrients.
If you decide to prepare a homemade dog struvite diet at home, consider having the recipe reviewed by a veterinary nutritionist, especially if you plan on giving such diet for prolonged periods of time.
Veterinarian Dr. Michael Salkin offers a home cooked recipe to prevent recurrence of struvite urinary stones in dogs, but he warns that it should be given only under veterinary supervision and the dog's urine pH should be monitored as well.
" Whereas all commercial pet foods must legally meet or exceed certain amounts of nutrients to be marketed as “complete and balanced foods”, studies have shown that the vast majority of recipes that pet owners design for their pets, or obtain from magazines, books, or the internet are deficient in one or more essential nutrients."~Dr. Cailin R. Heinze, veterinary nutritionist
- Hill's pet: Hill's® Prescription Diet® s/d® Canine
- DVM360: Improving management of urolithiasis: canine struvite uroliths