I always carry Gas-X in the event of suspected bloat. My vet recommends it to potentially buy you a little extra time on the way to emergency.  
we use Infant gas relief, or simethicone.  
Another thing that comes in handy, and I could see a use for in a survival situation,   
Rescue Remedy .  It calms dogs.  I have used it infrequently, but to great success.   
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