9 C.F.R. § 2.51 Form of official tag.
Title 9 - Animals and Animal Products
(a) The official tag shall be made of a durable alloy such as brass, bronze, or steel, or of a durable plastic. Aluminum of a sufficient thickness to assure the tag is durable and legible may also be used. The tag shall be one of the following shapes: (1) Circular in shape and not less than 1 (2) Oblong and flat in shape, not less than 2 inches by (b) Each tag shall have the following information embossed or stamped on so that it is easily readable: (1) The letters “USDA”; (2) Numbers identifying the State and dealer, exhibitor, or research facility (e.g., 39–AB); and (3) Numbers identifying the animal (e.g., 82488). (c) Official tags shall be serially numbered. No individual dealer or exhibitor shall use any identification tag number more than once within a 5-year period.
Title 9: Animals and Animal Products
PART 2—REGULATIONS
Subpart E—Identification of Animals
§ 2.51 Form of official tag.