RE: mineral feeds
It is thought that irradiaton of th eskin by ultraviolet light and consumption of irradiated plant tissues will meet the diet requiements for D.
Carotenes in green leaves can be converted to vitamin A.
In tests (1956) vitamin supplements were given with a low calcium diet and no improved antler development occured.
It has also been noted that depleted amounts of vitamin A also cause agression in cervids.