7 U.S.C. § 2141

Marking and identification of animals

All animals delivered for transportation, transported, purchased, or sold, in commerce, by a dealer or exhibitor shall be marked or identified at such time and in such humane manner as the Secretary may prescribe: Provided , That only live dogs and cats need be so marked or identified by a research facility.

( Pub. L. 89–544, § 11 , Aug. 24, 1966 , 80 Stat. 351 ; Pub. L. 91–579, § 12 , Dec. 24, 1970 , 84 Stat. 1562 ; Pub. L. 94–279, § 5 , Apr. 22, 1976 , 90 Stat. 418 .)