There are numerous reasons for an older dog, or any dog, to develop a cough including tracheal collapse, heart disease and pneumonia. Sometimes, the cough can be as simple as an irritated throat so when a cough develops make an appointment to see the vet to head off any larger issues.
Tracheal collapse may sound like a life-threatening issue, but more than 70 percent of dogs who suffer from a mild form of this do well with medical management. This situation is most common in small dogs like pugs. In cases where the condition is more severe, there are surgical options. This condition mostly causes the dog to cough when excited, tugging at their collar or drinking water.
In the case of heart disease, the coughing will normally begin after exercise, laying down or waking up. Dogs do not indicate heart failure or disease the same way humans do. This type of cough is normally consistent. The reason the cough occurs when a dog has heart disease is because the heart becomes enlarged and presses on the lungs.
Pneumonia can be found in dogs of any age, but is very common in older dogs. This condition will have a wet or productive cough to go along with it. Some types of pneumonia in dogs can come from accidentally inhaling vomit or gastric acids when sick. Others are caused by bacteria or fungal infections.