Your dog can’t tell you that he’s not feeling well, so it’s up to you to notice the signs that he’s sick or hurt and to do something to get him healthy again. Signs of illness in your dog include
A gastrointestinal upset may be accompanied by vomiting and/or diarrhea. If your pooch misses two meals in a row, get him to a veterinarian for tests.
Dogs may also lose weight when they’re suffering from cancer or when they’re eating a food that doesn’t provide them with the proteins and energy they need. Dogs also lose weight during prolonged illnesses if they aren’t eating, which is why encouraging your dog to eat just a bit when he’s ill is important, as long as he doesn’t have a digestive upset.
At the other extreme, if the stools are loose so that they form cow-patty-shaped piles or liquid pools, then your dog has diarrhea. Withholding food for a day should take care of that problem, but if your dog has diarrhea for more than 24 hours, take him to see your veterinarian.
Increased water consumption, on the other hand, can be a sign of fever, kidney failure, or hormonal disturbances, so if your dog has started drinking a lot more than he normally does, take him for a vet check.