Although diet can affect the production of crystals in a dog's urine, it doesn't necessarily cause them. A preventative diet can keep susceptible dogs from developing certain types of crystals, but such measures won't work on all types. Some canines have a genetic predisposition for crystal formation. If your dog's affected, ask your vet about the risks and whether a special diet is warranted.
While crystals themselves are not harmful, they can clump together, creating bladder stones. These stones can cause urethral obstruction, especially in male dogs. Urinary tract blockage is a red-alert veterinary emergency. Struvite crystals are the most common type formed in dogs. Affected canines usually develop these crystals as a result of bladder infection. Calcium oxalate crystals, the next most common type, form when the dog's kidneys do not excrete sufficient calcium or the intestines absorb excessive amounts of it. Urate crystals, often genetic in origin, form in Dalmatians and dogs suffering from liver shunt.
While any dog might develop urinary crystals, certain breeds are more prone to crystals and subsequent stones than others. These include the miniature schnauzer, bichon frise, Labrador retriever, Yorkshire terrier, Welsh corgi, Pekingese, pug, Lhasa apso, dachshund, beagle, Scottish terrier, Shih Tzu, cairn terrier, miniature and toy poodle, Pomeranian, Newfoundland, mastiff, Cavalier King Charles spaniel, cocker spaniel, bulldog and basset hound. Dalmatians are in a class by themselves, as as hereditary disorder often produces urate crystals and stones in the breed.
Unless your dog is suffering from a urinary tract disease, it's likely your vet will discover the presence of crystals in the urine during a routine urinalysis, part of your pet's annual checkup. If crystals are present, your vet might perform an ultrasound or X-ray to see if stones have formed in the bladder or kidneys. Treatment depends on the type of crystals and whether or not stones are an issue.
Dietary therapy can dissolve struvite stones, but not those consisting of calcium oxylate. Your vet might prescribe a low-protein, low-magnesium and low-phosphorus food devised to create acidic urine to get rid of struvite stones. Because struvite stones generally result from infection, she'll prescribe antibiotics to kill the bacteria. Calcium oxalate stones must be removed surgically, although small stones in the urethra might be removable via a catheter. Your vet might prescribe a diet low in protein, sodium and oxalate to prevent recurrence, which often occurs with this type of crystal or stone. Urate stones, the sort found in Dalmatians, can be dissolved with a low-protein, low-purine diet. Purines, a natural organic compound, form uric acid.
By Jane Meggitt
petMD: Crystals in the Urine of Dogs
VCA Animal Hospitals: Struvite Bladder Stones in Dogs
University of Minnesota: Canine Uroliths -- Frequently Asked Questions and Their Answers
Merck Veterinary Manual: Urolithiasis in Small Animals
Miniature Schnauzer Club of Canada: Canine Urolithiasis
About the Author
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.