You need to find a vet that will come out or get a trailer and haul her in NOW. Diahrea in adult horses is very serious and it's not something that the horse will get over in time. I had a horse get a bacterial infection and very nearly die in just a couple of days. He spent a week at the vet and lost probably 200lbs before it was all said and done.
There's nothing like the Rockies in the springtime... Nothing like the freedom in the air... And there ain't nothing better than draggin calves to the fire and there's nothing like the smell of burning hair. -Brenn Hill