Why is my dog breathing heavy out of her nose?
The diagnosis is based on medical history and clinical signs. Your veterinarian will rule out other causes of abnormal breathing and snorting, such as an upper respiratory tract infection, collapsing trachea, nasal tumors or polyps, foreign bodies in the nasal passages or mouth, and so forth.
Do dogs breathe through their nose when they sleep?
Dogs can breathe through either the oral cavity or nasal cavity when they are awake. However, they are obligate nasal breathers when asleep. Therefore, if their nose is blocked, dogs will wake up, open their mouth to breathe and subsequently go back to sleep.