Not really an answer but something that happened be to me. My yearling stud colt had an impaction colic here about a month ago, he was fine that morning when we fed and I went to work, came home and found TONS of hay in his stall, now this is a horse that is a pig. Thought it was odd so we fed everyone else and left his feed out and waited for his reaction, he was dying for his feed. So I was not thinking of him colicing, I thought maybe something was wrong with his hay, so we cleaned it up and offered him a different flake of hay and he dove right into his feed and hay, then all of a sudden he did what I was dreading, he rolled clear up onto his back and laid his head flat out and groaned. Got him up as he was thrashing around, had fiance call the vet, of course no answer. (only vet willing to take emergency calls in this area) I just kept him up and let him walk for 10 or 15 minutes and let him back in his stall for 10 or 15 minutes but we left him tied so he could not thrash because he kept trying. I gave mineral oil to him and just waited and walked and waited. I was up until 5 am with that horse after just working a 12 hour shift, luckily I was off the next day. Finally at 4 am we seen some poop that showed mineral oil in it so I stayed for one more time and then I went on inside and went to bed. Next morning he did just fine, have not had a problem since, which I am very happy about. I think my fiance might have fed him extra hay and since the weather was really cool I know he did not drink very much water that day(his bucket was just as full that night as it was when I refilled it that morning) and I am sure that was what has caused it.
You know how to make a miniature horse even smaller? Leave them in the dryer a little longer!
"Don't ever regret something that once made you smile"