Sniper is 9 months old and very healthy as far as I can tell. Now that the weather is getting nicer out, we have been going for walks. I started her out slow, just a few minutes for the first few walks, and have been building it up for a couple of weeks. After a couple of longer walks, she would do this coughing thing afterwards. The spells would only last a few minutes, with maybe 10 coughs total. My vet told me not to worry about it. I just got back from a longer walk today where she did a lot of running off leash, and it is about 65 degrees out. She was fine until we started heading for home where she was really breathing heavy, panting, and kept laying down to rest. I would let her and offer her water, which she took a couple drinks of but was not really interested in. She acted fine and happy, just really exhausted where she was almost dragging her feet. When she got home, she started coughing again, and then almost gagging, and then she would vomit up just a bit of white foam. Again, I offered her water, she took a few drinks and seemed ok. I watched her, she just lay on the kitchen floor still panting. She ate heartily, seemed fine, besides the coughing. She was still coughing and acting like she wanted to vomit up more foam, and couldn't seem to get comfortable when she was lying down, almost like she couldn't catch her breath. This went on for about 3 minutes, and now she is fast asleep. I am very concerned as I have never had one of my dogs do this. Is it she is just out of shape and this walk/run today exhausted her? Should I get her to the vets? What kind of testing would they do? Any ideas??