Wind problem, Breathing with mouth!

My horse have a problem when breathing under training, that happends only when he peform up to 100%..See this clip and turn the sound up. http://www.youtube.com/watch?v=noHjrCgQgOo

Have anybody seen something like this? For me it feels like he have what they call dorsal displacement of the soft palate (DDSP) or something similar.. I need help too prevent that happening, any suggestion?

The horse is an Norwegian cold blood trotter, 5 years of age with name Jesper

Hmm could he be huffy puffy from working a long time? Or did you just take him out?

I'm stumped!

He had done some training in front of that happening. Just before I jumped off the sulkey for making film. He had just finished the last interval in the training..4*ca 250 meters a little uphill

I say get the vet! :)

Definitely sounds like your horse is just displacing. Talk to your vet, and if there's a clinic nearby, i'd go have either tie-back, tie-forward, or laser procedure done. Considering, it's a fairly cheap and very easy procedure, and they only about 2 weeks off from it. It's usually (depending which one you do) about an 800-1200$ procedure, depending on which you do, where you're located, your vets, etc, etc.