So,sorry this happened. You can switch diets slowly. Responsible Bree keep pups for 10 weeks then have them heart checked by a cardiologist. Clearly your bree did not do that. So have that done especially if he is breathing heavily. Also get pet insurance. I have Embrace. Good luck with...
Calvin is now a Champion! He is now CH Sound Bay Calvin's Inclined By Design. He completed his Championship at the Walkill KC show at New Paltz, NY on June 19, 2014. He is a Dream Time Kosmo son.