No one knows your dog better than you do. It is extremely important to be on the lookout for signs that your dog could be sick.
Signs that you need to watch out for...
1. Lack of appetite - Anorexia is often one of the very first signs of illness in dogs. It can be difficult to determine if you feed your dog dry food only and keep the bowl full. For this reason, some veterinarians recommended feeding dogs a scheduled feeding at the same time every day so that you accurately assess their appetite.
2. Less active - Dogs that don't feel well are often less active. Many times this "less active" sign is mistaken for "getting older". If your dog is less active, the safest thing to do is have your vet check your dog out.
3. Weakness - Weakness can be displayed as either being "less active", having a lethargic appearance, or by displaying a loss of balance and coordination. All of these are potentially serious signs and should prompt immediate evaluation by your veterinarian.
4. Lethargy - Lethargy is a general lack of interest in the environment. It is a very common symptom and can be an early or late sign of illness depending on the severity.
5. Weight loss - Losing weight is another common sign of disease or illness. Sometimes it is difficult to notice weight loss, especially in longhaired dogs or dogs that you see every day and may not notice subtle changes. If your dog feels bonier, lighter, or you can easily feel the ribs, this could be a problem.
6. Increased water consumption - Drinking more is often associated with a few diseases including kidney disease and diabetes mellitus. If you notice your dog is showing these symptoms, see your veterinarian.
7. Changes in Coat - Dogs that don't feel well generally have a dull lusterless coat. If your dog's coat changes, have him or her evaluated by your veterinarian.
8. Bad breath - Bad breath, also known as halitosis, can result from dental disease as well as other metabolic disorders.