Choking
If a dog is having trouble breathing and it also is accompanied by coughing or gagging, it may be a sign that an air passage is blocked. Check for an object lodged in the dog's throat. It should be removed very carefully, so as to not push it back farther. If the object cannot be extracted, then try The Heimlich Method. If the cause cannot be found or removed, then immediate professional help is necessary. If the dog faints, the object will have to be removed right away to reopen the airway. Open the mouth, take hold of the neck in back of the object and apply enough pressure to the throat to keep the object from passing down while you hook it with your fingers. Work it loose as quickly as possible, then administer artificial respiration.
Prevention: Avoid giving your dog a hard rubber ball, chicken bones or long bones that spliner easily.