StacksVerified U.S. regulatory reference

21 CFR §558.4

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (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.
  2. (b)The manufacture of the following types of feed are exempt from the required license, unless otherwise specified:
    1. (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. (2)Type B or Type C medicated feed using Category II, Type B or Type C medicated feeds.
  3. (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.
  4. (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:
  5. (e)When drugs from both categories are in combination, the Category II requirements will apply to the combination drug product.