A friend of mine has a sheltie that has been having some urinary issues. A vet check revealed numerous crystals, but no stones. The vet put the dog on Science Diet (s/d canned for 2 weeks, then c/d dry) to prevent more crystal/stone formation but my friend would like to have her dog on a diet with more...

The usual formula for the formation of struvite crystals is: urea in the urine (from the breakdown of proteins) + urease (by-product of bacteria) + other compounds in the urine + high pH (from chemical reactions started by urea + urease) + magnesium ---> struvite crystals (magnesium ammonium phosphate...