Requirement of a medicated feed mill license.
21 C.F.R. § 558.4
in effectEffective: 2024-07-01(a) A feed manufacturing facility must possess a medicated feed mill license in order to manufacture a Type B or Type C medicated feed from a Category II, Type A medicated article.
(b) The manufacture of the following types of feed are exempt from the required license, unless otherwise specified:
(1) Type B or Type C medicated feed using Category I, Type A medicated articles or Category I, Type B or Type C medicated feeds; and
(2) Type B or Type C medicated feed using Category II, Type B or Type C medicated feeds.
(c) The use of Type B and Type C medicated feeds shall also conform to the conditions of use provided for in subpart B of this part.
(d) This paragraph identifies each drug by category, the maximum level of drug in Type B medicated feeds, and the assay limits for the drug in Type A medicated articles and Type B and Type C medicated feeds, as follows:
(e) When drugs from both categories are in combination, the Category II requirements will apply to the combination drug product.
Source: eCFRURL: https://www.ecfr.gov/api/versioner/v1/full/2024-07-01/title-21.xmlFetched: 7/26/2026
