This is a result of our exceptionally functional government. If a company adds IGR only in a mineral the EPA adds all these crazy regulations that nobody wants to deal with. So feed companies add monensin to their igr mineral, monensin is a drug and therefore regulated by the FDA. The FDA's regulations take president over the EPA's crazy regulations so the feed companies get to ignore the EPA regulations and just follow the FDA's. For instance if I recall correctly to sell an IGR only from a feed store it must be stored separately from everything else in a biosecure area. The monensin level should be whatever the FDA approved monensin to be fed at for cattle on grass, at worst the increased feed efficiency should at least pay for the added mineral cost. Keep an eye on intake though, monensin is known to be unpalatable. The warning is probably for the concentrated drug itself (rumensin 90) it must be mixed before being fed, which it probably has been by the feed company. Should be between 50 & 200 mg monensin/hd/d (FDA regulation). So assuming 50 lb. Bag and 4oz intake the tag should read between 625-2,500 mg monensin.