First, make sure that the teeth are looked at by a vet as there could be tarter build up, a rotten tooth, exposed roots that would require a dental. Dogs will more likely need at least one if not more dental cleanings in their lifetime. Usually we see the first dental warranted around 7 years of age. Some dogs even more often. A mouth full of tarter and bad teeth is very discomforting
If all is good then more likely the smell is coming from his stomach. Enzymes are then needed. A great product is Purina FortiFlora. You can find it online or at your local vet. Once packet of powder each day with food. You can buy this product at your vet or online.
Another thing to make a dog’s breath smell bad is if he is eating his own poop. Very common practice for puppy mill dogs or dogs not feed properly. Watch your dog when going outside to confirm if this is happening.
If poop eating:
Poop-eating has got to be one of the most disgusting habits of dogs. Unfortunately, the act of eating feces is relatively common in dogs. The reasons behind why some dogs eat feces are not entirely known, but there are a few theories: · Natural Behavior*: Mother dogs instinctively lick their pups clean, ingesting their feces. This is a normal behavior that keeps the pups and their environment clean. Many puppies will begin to eat feces at a young age. Some pups grow out of this normal behavior, while others continue this into adulthood. · Hunger and Food Obsession: A dog suffering from starvation or severe malnutrition might eat anything it can find. This is what we see most with dogs released from puppy mills. Some dogs, though well-nourished, are hungry all the time (this may be a sign of illness or the wrong diet). Many dogs are completely obsessed with food and will ingest anything that tastes good to them. Many dogs from puppy mills are not feed properly or daily thus they turn to their poop for nutrition and filler.
*Suggestion is getting your dog's stomach to feel content. This is done by increasing their kibble and adding healthy fruits and vegetables in between meals. Never allowing your dog to feel hungry so when they do poop they are too full to eat it. · Illness: Certain diseases and illnesses can cause a dog to eat feces. A symptom of some diseases is increased appetite or ingestion of inappropriate items. An illness that changes the consistency or smell of the stool might make a dog want to eat his own stool. Sudden onset of this behavior is cause for a veterinary exam. · Anxiety, Fear and Stress: A dog under a great deal of stress may eat his own stool. This may be a kind of self-soothing mechanism in some cases. However, if a dog is punished for inappropriate defecation or other action related to feces, he may associate the punishment with the presence of feces. By eating the feces, he is removing the"evidence" to avoid punishment. What are the risks of dogs eating feces? If a dog eats his own stool, it poses little danger to that dog. However, bacteria and parasites from that stool can be transmitted if they exist. Eating poop after treatment will just recontaminate the body. When a dog eats the feces of another animal (especially another dog or a cat), he is at risk for ingesting the eggs of intestinal parasites and potentially harmful bacteria that can easily lead to illness.
*How can I stop my dog from eating feces? Once you have ruled out medical problems as a cause for your dog eating feces, you are left with addressing the behavior. Because this is generally a self-rewarding behavior, it will take time and patience to stop the normal behavior. · First and foremost, make sure your yard is kept free of animal waste, and pick up your dog's stool as soon as possible after defecation. · For dogs that try to eat their own feces during or immediately after defecation, you must be on high alert. Keep your dog on the leash when defecating. If his attention goes to the feces, immediately turn his attention to you (try teaching the ‘look command’ or ‘leave it’).
· For dogs that cannot poop when you are standing around watching them consider using a water bottle. If they turn to smell or even look at the poop spray them creating a consequence.
· Add something to the dog's diet that makes the stool unpalatable. These products will not work for all dogs, but it will not harm your dog to try (as long as your dog is not allergic to any to the ingredients). Suggestions are adding crushed pineapple to the diet, meat tenderizer, sprinkling MSG over the food, or giving them “Deter” which is found at pet stores.