[Patricia A]

There are different types of stones with different reasons for formations. However, hydration is a big key in all stones to prevent recurrence. Helpful article below for Calcium oxalate stones.
Nutritional management of Calcium Oxalate stones

While it can be difficult to completely prevent your dog developing calcium oxalate stones (particularly if they have a genetic predisposition to it), there are some things that you can do to decrease your dog’s chances of developing bladder stones, and to prevent them coming back in dogs who have previously had them.

Keeping your dog well hydrated is vital. This dilutes their urine, which in turn dilutes the levels of chemicals that promote stone formation, and so decreases the chance of your dog developing bladder stones.

You can help your dog drink more water by placing a few bowls of fresh water in different locations around the house. Always make sure the water is fresh and that you change it regularly.

In the ideal world we are aiming to maintain urine specific gravity <1.020. I always encourage my clients to buy a refractometer, which makes it very easy to measure your dog’s urine specific gravity.

The food your dog eats also impacts on the development of calcium oxalate stones.

To decrease the chances of your dog developing bladder stones, you should avoid feeding foods that contain high levels of oxalate such as spinach, sweet potatoes, organ meat and brown rice. Instead, include foods with lower oxalate levels like apples (peeled), wild rice and meats and fish in their diet. It’s also a good idea to boil vegetables and discharge the water before giving them to your dog – this helps to reduce the oxalate levels in them.

Restricting calcium is another strategy for reducing oxalate levels in the urine – a reduction in calcium should be accompanies by a similar reduction in oxalate levels. However calcium restriction should be done very carefully, as too much restriction can be damaging and may lead to health problems including osteoporosis.

Other dietary measures that can be taken to help prevent formation of calcium oxalate stones are reducing dietary sodium (salt) and avoiding excess vitamin D. This is because excess sodium and vitamin D promotes excessive urinary calcium excretion. Therefore moderately reduce dietary sodium, stay away from high sodium treats and do not supplement with vitamin D.

Vitamin C supplements are not recommended because when vitamin C is metabolised and broken down, it produces oxalate – therefore avoiding vitamin C supplements avoids an increase in oxalate levels.

Vitamin B supplements are water soluble and are excreted in the urine. Therefore in all cases of urinary tract stones it is prudent to give a vitamin B complex supplement.

There is still some debate surrounding magnesium and bladder stones. Some studies have shown that magnesium in the urine impairs formation of calcium oxalate stones. But other studies have shown that when given to healthy dogs, magnesium supplements resulted in an increase in urinary calcium levels. So because there is no definite consensus, restricting or supplementing magnesium is not recommended and so both should be avoided.

It’s important to note that not all of the oxalate in your dog’s body stems from their diet. Some is produced naturally by your dog’s body, mainly the liver. Nonetheless, avoiding incorporating foods with high levels of oxalate in your dog’s diet is an important preventative step against calcium oxalate stones.

Including fiber in the diet may reduce absorption of some minerals and so should be considered as part of any dietary changes being made. However, take care not to increase levels too much which can result in overfeeding.

Calcium oxalate stones cause the bladder to become inflamed by rubbing up against the bladder wall. To help reduce this inflammation, you can give your dog fish body oil supplements. However, avoid liver oil as this contains vitamin D which should be avoided (see above).

There are a few veterinary prescription diets designed to (theoretically) reduce the likelihood of calcium oxalate stone.

You can also prepare you dogs food at home using the same high quality ingredients that you eat. There are several health benefits of making your dogs food at home. By feeding your dog a home-prepared diet rather than a dry kibble diet, you can increase the amount of water they are drinking. And as mentioned above, increased water consumption makes urine more dilute and can help prevent stones forming.

A home-prepared diet is also the only way you can truly control what is going into your dog.

If you’d like to try cooking for your dog, the best way to ensure that the diet is meeting all of your dogs nutritional needs is to get your recipe from a qualified nutritionist. Dietary manipulation to address a health problem should be done by someone who will work with your dog.