Basic oatmeal is probably fine for most dogs. For a dog with some sort of medical compromise, it's best to refer directly to the vet providing ongoing care. I'd suggest avoiding additives, flavorings, sweeteners unless absolutely necessary but oats are a basic component of many of the natural dog treats for sale these days. I would never make oats the major portion of a dog's diet since they need the variety they would find in nature but that would depend on your specific situation.
yes, you can feed your dog oatmeal. It is good for dogs allergic to wheat and upset stomach. Make sure you have cooked oatmeal before serving to your dog. You should always consult with a veterinarian before doing major changes in your dogs diet.
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I would say a definite YES. Oatmeal is one of the best diet for your pet. As a matter of fact i've been usng oatmeal on priority when it comes to feeding my lovely pet. However, the oatmeal must be of some branded quality. Don't use the homemade ones. They may disrupt his digestive system.