Collapsed Trachea
Usually this is a problem with small dogs, especially dogs of the toy group. The symptoms of a collapsed trachea include noisy breathing and frequent coughing. Sometimes dogs seem incapable of catching their breath.
The trachea is normally a rigid tube. In an affected dog, the trachea is somewhat soft, so it tends to narrow from time to time. This obviously impedes air flow. Most dogs learn to live with their problem, as do their owners, once they understand that it is rarely life threatening. Obesity, stress, and pressure on the trachea should be avoided. It's best not to use a collar on a dog with a collapsed trachea- go for a harness instead. Surgery can help severely affected animals.
What breeds tend to have collapsed trachea? Yorkshire Terriers, Pomeranians, Chihuahuas and Dachshunds.