{"data":{"id":"us/21-cfr-558.254","jurisdiction":"us","citation":"21 CFR 558.254","heading":"Famphur.","body":"(a) Specifications. Type A medicated articles containing 13.2 or 33.3 percent famphur.\n(b) Sponsor. See No. 000061 in § 510.600(c) of this chapter.\n(c) Related tolerances. See § 556.273 of this chapter.\n(d) Special considerations. Famphur is a cholinesterase inhibitor. Do not use this product in animals simultaneously or within a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals.\n(e) Conditions of use. It is used in cattle feed as follows:\nFamphur amount Indications for use Limitations Sponsor\n(1) To provide 1.1 milligrams per pound (mg/lb) body weight per day Beef cattle and nonlactating dairy cattle: For control of grubs and as an aid in control of sucking lice Feed for 30 days. Withdraw from dry dairy cows and heifers 21 days prior to freshening. Withdraw 4 days prior to slaughter 000061\n(2) To provide 2.3 mg/lb body weight per day Beef cattle and nonlactating dairy cattle: For control of grubs Feed for 10 days. Withdraw from dry dairy cows and heifers 21 days prior to freshening. Withdraw 4 days prior to slaughter 000061","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":"1947e5d13adfdf6ad198b6a399788f10a43021dbe20354866799c7de71413799","source_id":"us-cfr","stale":true,"prev":"us/21-cfr-558.248","next":"us/21-cfr-558.258"},"notice":"GroundRules: Original legal text. Not legal advice."}