Almost all Kidney stones are Calcium Oxalate / CaOx stones, & although they can be present in the bladder they are more often found in the kidneys. Wherever they are located they generally show themselves as blood or calcium oxalate crystals in the urine.
Whilst the presence of crystals is a concern, it does not necessarily mean your dog is at risk of forming (or has formed) stones. Crystals are only truly significant if found in very fresh urine (30 minutes old max) because they can form during storage & refrigeration. Often therefore vets seek to monitor & re-test more than once before drawing any firm conclusions.
The accepted wisdom on how to feed a dog prone to kidney stones is somewhat mixed but feeding a food that contains predominately low oxalate ingredients may be a good idea. Low oxalate ingredients include meat & fish of all kinds, white rice, corn/maize, oats, brown rice, peas & white potatoes (avoid all but the smallest quantities of barley, wheat/cereals & sweet potato).
Although recent research suggests that reducing protein & phosphorus is not necessary, it’s our experience that many vets believe this to be a good idea. Obviously, it’s important that you follow your vet’s advice on this, so we’ve listed a range of foods that contain low-oxalate ingredients but with different protein & phosphorus contents.
What is universally agreed upon is the importance of ensuring your dog drinks lots (& lots) of water &, equally important, that they can relieve themselves at regular intervals. Holding urine causes it to become more & more concentrated which in turn provides an ideal environment for the crystals to form into stones. Distilled water is much preferable to tap water (and there are many tap-water distilling jugs available). In addition, using bottled mineral water in between meals has recently been shown to have a favourable effect on reducing stone formation.
We therefore highly recommend adding distilled/tap water to their dinners &, if possible, putting mineral water in their water bowl.