is most often seen in very young dogs or puppies of small size as a genetic defect. It is caused by the absence of the cartlidge rings in an area of the trachea. It is characterized by a "gag" reflex (not a cough) as the trachea collaspes and shuts off the air momentarly. The gag sounds almost like the dog is ready to vomit, but it never does. This usually occurs after strenuous exercise, but can occur under other conditions such as excessive panting leaving the trachea dry. Usually the young dog will either outgrow it, or it may necessitate surgery to repair if it becomes severe.

It would be very rare for an older dog to suddenly develop this condition. Presumably a light scope was stuck down the trachea of your dog to diagnose this problem? If not there are other possible causes.

Torbutrol is a very potent morphine pain killer for dogs. The sedative effect would probably inhibit the coughing reflex. As a morphine like compound your dog may over time build up a tolerance to the current dosage.