{"data":{"id":"us/21-cfr-558.274","jurisdiction":"us","citation":"21 CFR 558.274","heading":"Hygromycin B.","body":"(a) Specifications. Type A medicated articles containing 2.4 or 8 grams hygromycin B per pound (g/lb).\n(b) Sponsor. See No. 058198 in § 510.600(c) of this chapter for as follows:\n(c) Related tolerances. See § 556.330 of this chapter.\n(d) Special considerations. (1) Federal law restricts medicated feed containing this veterinary feed directive (VFD) drug to use by or on the order of a licensed veterinarian. See § 558.6 for additional requirements.\n(2) The expiration date of VFDs for hygromycin B medicated feeds must not exceed 6 months from the date of issuance. VFDs for hygromycin B shall not be refilled.\n(e) Conditions of use. It is used in feed as follows:\n(1) Chickens—\nHygromycin B grams/ton Combination in grams/ton Indications for use Limitations Sponsor\n(i) 8 to 12 Chickens: For control of infections of large roundworms (Ascaris galli), cecal worms (Heterakis gallinae), and capillary worms (Capillaria obsignata) Use in complete feed. Withdraw 3 days before slaughter 058198\n(ii) [Reserved]\n(2) Swine—\nHygromycin B grams/ton Combination in grams/ton Indications for use Limitations Sponsor\n(i) 12 Swine: For control of infections of large roundworms (A. suis), nodular worms (O. dentatum), and whipworms (Trichuris suis) In market hogs, use in complete feed for 8 weeks during the growing period. Withdraw 15 days before slaughter 058198\n(ii) [Reserved]","path":["Title 21—Food and Drugs","CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER E—ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS","PART 558—NEW ANIMAL DRUGS FOR USE IN ANIMAL FEEDS","Subpart B—Specific New Animal Drugs for Use in Animal Feeds"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-21.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:47Z","sha256":"52992bc172f8c362f1f7e6ae6c92db6b23d57287c8bef8d2f913d600cf4f0acf","source_id":"us-cfr","stale":true,"prev":"us/21-cfr-558.265","next":"us/21-cfr-558.295"},"notice":"GroundRules: Original legal text. Not legal advice."}