If your dog is getting a high-quality, complete diet already, they do not need any zinc supplements. If you are unsure, look for diets that meet all of the AAFCO's guidelines for dog food. It is also important not to over-supplement your dog with zinc, as zinc toxicity can be deadly. If in doubt about your dog's nutrition, it's always best to talk to your vet for advice. They can refer you to a veterinary nutritionist to discuss your pet's needs.