You have not pointed out that how many weeks your dog is pregnant? Panting is usually associated with pain. Dogs have panting during start of labor because uterine contractions during labor cause sever pain. This condition can result in to panting, pacing, restlessness, Shaking and nervousness. These signs appear when true labor starts.
If your dog is panting other than at the time of labor then take her to vet for diagnosis and treatment.
If your dog is panting other than at the time of labor then take her to vet for diagnosis and treatment.
