4. Livers (including sliced livers) of bovine animals, swine and solipeds shall be hot-branded with the health mark and all other offal, unless it is wrapped or packaged in accordance with the requirements of Schedule 13, shall have the health mark applied in ink or hot-branded, save that, in the case of bovine animals under three months old, and swine, sheep and goats, health marking of tongues and hearts shall not be compulsory.