Dogs breathe through a series of airways that comprise the nasal passages, throat, windpipe, and bronchial tubes that lead to the lungs. Any of the following symptoms indicate a problem in the system:

• Rapid breathing

• Noisy breathing

• Coughing

Dogs will breathe heavily and rapidly in a number of circumstances, such as after strenuous exercise, in excessive heat, or if they're excited or stressed. If your puppy is breathing rapidly while at rest and you can't attribute any of these other factors to his condition, consult your veterinarian.

Noisy breathing includes wheezing, sneezing, labored breathing, hoarseness, and any odd sound the dog makes while trying to breathe. Owners of some short-faced breeds live with this problem. Their dogs have shorter airways and will regularly snort, snore, or breathe heavily. For other dogs, noisy breathing is generally due to an obstruction, though it can also indicate a lung disease or heart failure. It's best to have your veterinarian listen and look.

Coughing results from the effort to extricate an obstruction in the airways, whether it's a bone chip, a collapsed windpipe, or a fluid build-up in the lungs caused by a respiratory disease like kennel cough. Kennel cough is highly contagious between dogs and can spread rapidly at a dog show or in a kennel. There is a vaccine to help prevent kennel cough, and if caught early treatment is successful.