Collapsing Trachea in Dogs
Tracheal collapse is a common cause for coughing in toy and small breeds of dogs. Breeds that have a higher incidence are Yorkshire Terrier, Toy Poodle, Chihuahua, Pomeranian and Shih Tzu. Typically dogs are middle age and older when diagnosed, but this can happen at an earlier age.
Collapsing Trachea in Dogs: https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951968