USDA APHIS requires an import permit and health certificates from the exporting country's competent authority for bovine semen. The semen must originate from an approved collection center, and shipments are subject to inspection at designated ports of entry.

Subheading 051191 is limited to inedible products of fish, molluscs, crustaceans, and other aquatic invertebrates — such as fish waste, fish bladders, and similar byproducts. Subheading 051199 covers all other animal products not elsewhere classified, including animal hair, gut, bladders from terrestrial animals, and similar miscellaneous materials.