Re: Heavy Breathing
I might be underestimating what you mean by heavy breathing, but based on your saying that it only happens in the summer with higher temps and that he gets better after cooling off in the lake, it sounds like the heat is the culprit. If his tongue swells and hangs low out of his mouth, he pants heavily, and his eyes turn red, then he's overheating. Dogs aren't as efficient as cooling off as we are, so I'd bring a bottle of water for him to drink from during the walk or to pour on him periodically to cool off. If your climate isn't too humid, you could try one of those evaporative cooling jackets for dogs.