Unfortunately, I can only tell a sad story related to this...
My first pony died from a twisted gut which he got from a severe case of colic...the little ****** managed to break out of his field, into the grain shed and ate his head off before we came home and discovered him. Way too smart and greedy for his own good.
My mom is a vet. At the time she said surgery possibly could have saved him, but it was a slim chance at best. Also, we lived nowhere near a facility with the equipment needed for equine surgery, so even if they were able to get in and fix the problem, the chances of infection were almost assured.
On the positive side, your mare doesn't seem to be as bad as my pony was...he was completely blocked with no signs of improvement and was euthanized after about 42 hours.