Beware, using flash on dog might produce red eyes effect on your photo which is very obvious.
If you are covering the show/demo, it is always good to ask the orgainser, try not to shoot flash direct at the dog when they are doing stunt, maybe at angles.
I did once for SKC, good experience. Also remember that if it is indoor, you need fast lens and use a higher ISO so as to freeze action else you will get all the motion blur... depend on what you want.
Just to take note, in the competition area, normally they dun allow flash photography unless you are the official photograher.
Just my 2 cents