(a) Urea and other nonprotein nitrogen products defined in the official publication of AAFCO or by the commissioner are acceptable ingredients only in commercial feeds for ruminant animals as a source of equivalent crude protein and are not to be used in commercial feeds for other animals and birds.

(b) If any commercial feed contains more than 8.75 percent of equivalent crude protein from all forms of nonprotein nitrogen, added as such, or the equivalent crude protein from all forms of nonprotein nitrogen, added as such, which exceeds one third of the total crude protein, the label shall bear adequate directions for the safe use of such feed and the precautionary statement: “CAUTION: USE AS DIRECTED.” The directions for use and the caution statement shall be in type of such size so placed on the label that they will be read and understood by ordinary persons under customary conditions of purchase and use.

(c) On labels such as those for medicated feeds which bear adequate feeding directions and/or warning statements, the presence of added nonprotein nitrogen shall not require a duplication of the feeding directions or the precautionary statements, provided those statements include sufficient information to ensure the safe and effective use of the product due to the presence of nonprotein nitrogen.