Dog food and urinary stones
You have just learned that your dog has urinary stones or on the contrary you wish to prevent the appearance of urinary stones in your dog, the diet can play a big role in these two cases.
How are calculations formed?
Urinary stones or urolithiasis are defined as the presence of macroscopic mineralization in the urinary system, ranging from grain of sand to stone (pebble). These diseases constitute approximately 18% of the reasons for consultation with the veterinarian.
The most common symptoms are the presence of blood in the urine, a small increase in urination, difficulty in urinating or even inability to urinate in severe cases.
The minerals are naturally present in the urine, in dissolved form, and are eliminated during urination. The increase in their concentration and / or the modification of the urinary environment (pH, infection, morphological anomaly, metabolic disorder) lead to their crystallization and the formation of stones.
Four types of calculus are encountered in dogs:
- ammonia-magnesium or struvite phosphates,
- calcium oxalates,
- ammonium urates,
- cystine stones.
Struvites and oxalates are the most frequently found crystals. The appearance of stones is influenced by race, sex, age, diet, anatomical abnormalities or infections of the urinary tract.
All dogs can develop these diseases, however certain breeds are predisposed:
- The Dalmatian, the French Bulldog, the Bulldog and the Yorkshire are affected by urate urolithiasis.
- Dachshund, Yorkshire, Cairn Terrier, Irish Terrier, Basset Hound, Chihuahua, Pekingese, Tibetan Terrier, Boxer, Labrador, Brittany Spaniel, Poodle, Newfoundland and Bulldog are predisposed to the formation of cystine stones, by a hereditary phenomenon which induces an oversaturation of the urine into cystine crystals.
The diagnosis of these diseases is based on symptoms and urine tests. Other examinations will look for the contributing factors.
Role of food in stone formation
The formation of struvites is influenced by the presence in the urine of magnesium, ammonium, phosphate, an alkaline urinary pH, an unbalanced diet, genetic predisposition and especially urinary tract infection.
The formation of oxalate stones is influenced by the saturation of urine with calcium and oxalate (diet) and diseases that modify calcium metabolism (intestinal calcium absorption disorder, hyperparathyroidism).
Dalmatians have a metabolic peculiarity which leads to significant urinary excretion of urate. In addition, any serious liver dysfunction can lead to the formation of urate uroliths in dogs.
A diet with a high purine content (organ meats), insufficient consumption of water, an acidifying and protein-rich food are factors favoring the appearance of urate crystals in the urine.
The production of cystine crystals is due to a genetic disorder (detected in almost 60 breeds) of the metabolism of certain amino acids including cystine. They mainly appear on male dogs.
Cystine is found in particular in: brewer’s yeast, wheat germ, cabbage, dairy products, seafood, fish, eggs and meat.
How to treat and prevent urinary stones?
Increase the amount of urine
Large volumes of urine and frequent urination help flush out the free crystals that form in the urinary tract. To encourage water consumption, different strategies are possible:
- Give a food that contains a lot of water (household ration or wet industrial food) or add water to the croquettes.
- Slightly increase the salt content of food.
Be careful, foods that are too high in salt favor calcium oxalate stones .
Food in stone treatment
Calcium oxalate stones cannot be dissolved medically and require surgery to remove them.
For other types of calculation, medical and food management can allow the calculation to melt; in the event of failure, the surgical option will however be chosen.
A number of urolithiasis are the consequence of a urinary tract infection that should also be treated. Favorable causes are also treated.
Treatment of struvite stones
The food used to dissolve struvite stones contains:
Moderate protein content 15 to 20%.
Highly digestible nutrients.
Few fibers to reduce water loss from faeces.
High salt content.
This food is given at least for a month after the surgical removal or the dissolution of the stones, the dog then returns to a normal diet. The disappearance of the calculus is checked by radiography or ultrasound.
Thanks to this diet, symptoms generally subside in two weeks; the average time for dissolution of the calculations is 3 months.
Examples of daily household ration for a 10 kg dog
|Example 1||Example 2|
|Chicken: 100 g||Veal, chuck: 140 g|
|Whole hard-boiled egg: 18 g||Beef 5% fat: 35 g|
|Cooked rice: 200 g||Cooked rice: 145 g|
|Wheat bran: 10 g||Wheat bran: 18 g|
|Brewer’s yeast: 3.5 g||Tomato: 9 g|
|Rapeseed oil: 18 g||Rapeseed oil: 9 g|
+ Mineral and vitamin supplement low in magnesium
Prevention of calcium oxalate stones
Oxalate stones cannot be dissolved, they are surgically removed. At the end of the operation, these dogs benefit from a preventive diet since the recurrence rate is generally high, at 50% in the two years that follow if nothing is done.
The food should not acidify the urine.
The food should contain normal levels of protein, calcium and phosphorus.
However, treatments or food supplements containing calcium, vitamin D, excessive levels of vitamin C should not be given.
The watering must be stimulated: moderate addition of salt in the ration, addition of water (wet the kibbles) or wet feeding.
(Beware of certain drugs such as diuretics which promote the excretion of calcium in the urine).
Treatment and prevention of urate stones
The diets recommended in the dissolution of urate stones are formulated from vegetable proteins, egg and dairy products, in order to maintain a high level of overall proteins, to limit the quantity of purine and to obtain a pH high urinary (alkaline). Again, adding water to the kibble or a wet diet favorably increases urine volume.
> These are conventionally dietary regimes for chronic renal failure.
In addition to food, medications may be prescribed by your veterinarian to help dissolve the stone or prevent it from recurring.
This diet, inducing a low urine pH, and poor in purine (present in high quantity in particular in meat, anchovies, legumes, cocoa, brewer’s yeast), is maintained to avoid recurrences.
However, a diet low in purine is not necessary for Dalmatians who do not have urate stones, we will simply avoid acidifying foods and too rich in protein.
Treatment and prevention of cystine stones
A hypoprotein diet allows the dissolution of cystine stones. However, this type of diet is deficient in certain essential amino acids (carnitine, taurine) which will therefore have to be added, at the risk of causing heart disease.
As a prevention, a food with moderate to low protein content, which promotes the formation of alkaline urine, can be effective.
There are other types of crystals, the management of which is specific to your veterinarian.
The diet presents a major lever for the treatment and prevention of urinary stones in dogs. It depends on the nature of the calculation.
CAUTION: The elements mentioned here concern the adult dog without any other pathology. The diets will have to be adapted in the puppy, the pregnant or lactating female or during a concomitant illness.