Symptoms of kennel cough in dogs include coughing three to five days after their stay, white foam coming out of the mouth, a low-grade fever and an unproductive cough. Discover how dogs with kennel cough will often retch and gag with help from a veterinarian in this free video on kennel cough symptoms in dogs. Expert: Gregory McDonald Contact: www.petpointers.com Bio: Dr. Gregory McDonald earned his Doctor of Veterinary Medicine degree from Ohio State University in 1979.