A dog who's under the weather works hard to convince you she's just fine. That comes from thousands of years of instincts. In the wild, an obviously sick or weak animal (even a predator) is as good as dead. Even though she doesn't have to worry about that too much anymore, your dog's instincts still tell her to hide any signs of illness. You'll need a sharp eye and good observation skills to catch some of the more subtle clues. Of course, the better you know your dog, the easier it will be.
Some of the things to look for are basic: the way your dog looks, acts, eats, and drinks. For instance, she might look like she's gained weight, even though her appetite hasn't changed much, or like she's losing weight, even though she's eating more. A ten percent change in weight (which could be as little as a pound in a small dog) is something to bring to your vet's attention.
Usually, we know our dog is feeling good when she chows down on her food. It's not unheard of, though, for her to skip a meal or two, especially if it's hot outside. Any more than that is something to be concerned about. If your dog turns up her nose at food for more than two days, call your vet right away. Some diseases and medications cause dogs to develop eating habits that are downright out of the ordinary for them. A dog who has never been a food thief and suddenly starts raiding the garbage can or stealing food off the dinner table is telling you she needs a checkup or an adjustment of her medication.
A dog who starts drinking water like a fish could be developing diabetes or kidney disease. You may not be able to notice the dog's extra water consumption easily, but you should be able to pick up her increased intake by paying careful attention to what comes out the other end. She'll be producing much larger amounts of urine and have to go outside more often. She may also start having accidents in the house.
A healthy dog has a thick, shiny coat. A dull coat or one with rough, dry, or bald patches is a sign that something's not right. The problem could be the type of food your dog is eating, a flea allergy, or another skin problem. Whatever the case, your vet's advice will help put your pooch back on the right track.
A more subtle sign of illness is what veterinary texts call "lethargy." (In simple terms, it means laziness or sluggishness.) A dog who's lethargic might show no interest in going for a walk, even though that's usually the highlight of her day. She doesn't want to play, not even her favorite game of fetch the tennis ball. Now, sometimes lethargy can be chalked up to a hot day, being sore after an extra long walk, or just feeling out of sorts. If it continues for more than two days, though, talk to your vet.
A familiar and not-so-subtle sign of illness is vomiting. Vomiting is not as dramatic a thing in the dog world as it is for us, and dogs may even vomit deliberately to get rid of something that doesn't agree with them (yesterday's garbage, for instance). Occasional mild vomiting usually isn't anything to worry about. But if your dog vomits frequently or several times in a row, has a fever, seems to be depressed or in pain, or has bloody or forceful vomit, you should call the vet immediately.
Finally, go on poop patrol. As unpleasant at it may sound, your dog's stool is a clue to her health. A healthy dog's stools are small, firm, and moist. Dry, hard stools that cause your dog to strain on elimination may be a sign your dog isn't getting enough water, or it may be a hint of another dietary or health problem. Squiggly, rice-shaped segments in the feces indicate worms. It's not unusual for an occasional stool to be loose or liquid or to contain mucous or even a tinge of blood. But diarrhea, straining, or mucous- or blood-tinged stool lasting more than two days should prompt a visit to the vet. If the elimination problem is accompanied by other signs -- fever, vomiting, lethargy, loss of appetite, bloody diarrhea -- call the vet immediately.
In the next section, we'll cover a crucial aspect of dog-care: how to prevent illnesses in the first place. Read on.