Can a Dog on a Urinary Diet Have Treats?
Small amounts are usually fine, but treats can undo the diet if they're salty, high in minerals or make up a big part of what he eats. Keep treats under about 10% of daily calories, and ask your vet whether the diet's maker offers matching treats, or use pieces of the urinary food itself as rewards.
Your vet may recheck his urine after a few weeks on the diet; if the crystals return, cut back on extras.
See bladder stones in dogs and urinary tract dog food.
This is general information, not a diagnosis. Please follow your own vet's advice.