Adding salt to feeds is turning out to be the 'nutritional tip of the century'!!
Horses grazing green, growing, over-grazed or otherwise stressed grass can be ingesting many times the amount of potassium per day than they require.
As potassium is involved in cell division it is always in the tips of the leaves so in this respect short grass is worse. Also high in potassium are lucerne, molasses, protein meals and many herbs.
Also assists in the absorption of magnesium