Some horses over here get literally bucket-loads of sand in their gut, and
when it gets to that stage very aggressive therapy is pretty much all that
will shift the sand. We are fortunate that we can get the horse's adbomen
radiographed to get an idea of the quantity of sand. Once the initial colic
incident has passed (ie don't do this with a colicky horse) we will drench
with psyllium (we use some human products, the actual amount varies
depending on the concentration of the product) mixed in 5 litres of water,
and may do this daily for a week, monitoring the horse for colic (they can
get painful as the sand shifts) and for passage of sand. Like the TV shows
say, this is not something I would try at home. My impression is that
feeding psyllium is a very good at preventing sand accumulation, but may not
be aggressive enough to shift the sand.
I can't be any help about the possibility of enteroliths, but if the horse
continues to colic it is worth chatting to the vet and getting it checked
some more.
Anne
Western Australia