My Great Pyrenees Is Breathing Heavily, What Is Wrong ?

If your dog is breathing heavily after exercise or due to hot and humid environment then it is normal. Heavy breathing in dogs is can be attributed to oxygen deficiency and and pain. Pain can be due to variety of reasons. Oxygen deficiency can be due to

1. Lung diseases
2. Pneumonia
3. Trauma
4. Heart disease
5. Pulmonary edema
6. Bleeding in lungs
7. Obstruction of air passage

So, ideally, you should take your dog to vet for accurate diagnosis and treatment.