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Food Safety and Drug Residue Avoidance Definitions


Animal Medicinal Drug Use Clarification Act of 1994 (AMDUCA) allows veterinarians to prescribe extra-label uses of certain approved animal drugs and approved human drugs for animals under certain conditions. Extra-label use refers to the use of an approved drug in a manner that is not in accordance with the approved label directions. The key constraints of AMDUCA are that any extra-label use must be by or on the order of a veterinarian within the context of a veterinarian-client-patient relationship, must not result in violative residues in food-producing animals, and the use must be in conformance with the implementing regulations published at 21 CFR Part 530. A list of drugs specifically prohibited from extra-label use appears in the Code of Federal Regulations.

Animal Classifications

The term "non-lactating dairy cattle" is defined by FDA as those under 20 months of age which includes replacement dairy heifers, replacement dairy bulls, and dairy calves, according to current animal industry standards and a long standing FDA practice. These classes of dairy cattle have not yet, or would never produce, milk for human consumption. The term non-lactating dairy cattle does not include dry dairy cows. Dry dairy cows have previously produced milk for human consumption and will again in the future after completion of the "dry period" between lactations.

Dairy Cattle (cattle intended for production of milk for human food)

  • Lactating Dairy Cows - Female dairy breed cattle that are producing milk.
  • Dry Dairy Cows - Female dairy breed cattle that had previously lactated, but which are not currently producing milk (cows between two lactations).
  • Non-Lactating Dairy Cattle
    • Replacement Dairy Heifers - Female dairy breed cattle from weaning until first calving
    • Replacement Dairy Bulls - Intact male dairy breed cattle intended for reproductive purposes.
    • Dairy Calves - Female or male dairy breed cattle being fed a ration that includes milk or liquid milk replacer and which are not intended for veal production.
  • Veal Calves
    • Immature cattle (including dairy breeds) pre-ruminating animals and intended for meat production. They are recognized as a separate class from suckling calves because of their handling, housing and proximity to slaughter.

From Appendix III. Species and Classes of Major Food Animal; CVM Guidance for Industry #191.

Animal Drug Classes

There are three classes of animal drugs: Over-the-Counter (OTC), Prescription (RX), and Veterinary Feed Directive (VFD).


An antibiotic is a chemical substance or compound that kills or reduces the growth of susceptible bacteria. An antimicrobial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Therefore, an antibiotic is an antimicrobial drug that attacks bacteria.


Center for Veterinary Medicine regulates the manufacture and distribution of food additives and drugs that will be given to animals. These include animals from which human foods are derived, as well as food additives and drugs for pet (or companion) animals. CVM is responsible for regulating drugs, devices and food additives given to, or used on, over one hundred million companion animals, plus millions of poultry, cattle, swine and minor animal species (species other than cattle, swine, chickens, turkeys, horses, dogs and cats).

Extra-Label Drug Use

ELU refers to the use of an approved drug in a manner that is not in accordance with the approved label directions. Examples of extra-label drug use:

  1. Changing the dose, such as giving more penicillin than is listed on the label.
  2. Changing the route of administration, such as giving Flunixin intramuscularly (IM) or subcutaneously (SQ) instead of intravenously (IV).
  3. Changing the frequency of use, such as giving SpectramastTM LC twice a day instead of once a day.
  4. Giving a drug to a different production class of animal, such as using Nuflor® in a lactating dairy cow.
  5. Giving a drug for an indication (disease) not listed on the label, such as using Excede® for diarrhea.
  6. Changing the withholding times, such as not following milk withholding times for fresh cows after dry treatment administration.
  7. Changing the amount of drug per injection site.
  8. Changing the duration of therapy.


Food Animal Residue Avoidance Database is a national, USDA sponsored, cooperative project, with a primary mission to prevent or mitigate illegal residues of drugs, pesticides and other chemicals in foods of animal origin. Producers should discuss FARAD-specific information regarding withdrawal times, especially for extra-label drug use. FARAD provides: Advice on residue avoidance or mitigation; VetGram search for required withdrawal times for approved food animal drugs; FARAD-recommended withdrawal intervals for extra-label use of approved food animal drugs.


Food and Drug Administration. Under the direction of the Department of Health and Human Services.


Food Safety Inspection Services enforces the levels of residues, if any, of animal drugs that are established by FDA. FSIS is under the direction of the Department of Agriculture. FSIS derives its authority from the Federal Meat Inspection Act of 1906, the Poultry Products Inspection Act of 1957, and the Egg Products Inspection Act of 1970. They inspect meat and poultry products to ensure that there is no misbranded or adulterated products being put into the stream of commerce.

FSIS HACCP program implemented at slaughter facilities identifies the animals most likely to have drug residues. Animals that display lameness, injection site lesions or signs of illness are targeted for testing.


Food Safety Modernization Act was signed into law 1/2011. It aims to ensure the U.S. Food Supply is safe by shifting the focus of federal regulators from responding to contamination to preventing it.

Green Book

Published by the FDA is a list of all animal drug products approved for safety and effectiveness. It is updated monthly.


Over-the-Counter (OTC) drugs can be sold by any person or establishment without the prescription of a veterinarian.

Prescription (Rx)

Prescription (Rx) drugs can only be sold to the farmer by a veterinarian or pharmacist, and only with a prescription from a licensed veterinarian.

Repeat Residue Violator List

Repeat Residue Violator List for Use by FSIS Inspection Personnel maintained by FSIS that contains the names and addresses of producers who have more than one meat residue violation in a 12-month period in animals presented for slaughter.

Residue Repeat Violator List

Residue Repeat Violator List for Use by Livestock Markets and Establishments maintained by FSIS that contains similar information intended to assist plant owners and operators in identifying residue history of livestock suppliers. This second list documents only the source name and address information of repeat violators, so that livestock marketers and buyers may use precaution when marketing and processing animals from listed suppliers.


The United States Department of Agriculture (USDA) Food Safety Inspection Services (FSIS) conducts tests for chemicals—including antibiotics and various other drugs, pesticides and environmental chemicals—in meat, poultry, and egg products destined for human consumption.

Scheduled sampling plans consist of the random sampling of tissue from healthy-appearing food animals. The development of scheduled sampling plans is a process that proceeds in the following manner:

  1. determine which compounds are of food safety concern;
  2. use algorithms to rank the selected compounds;
  3. pair these compounds with appropriate production classes; and
  4. establish the number of samples to be collected.

Veterinary Feed Directive

A VFD is any drug intended for use in animal feeds or water, and such use of the VFD drug is permitted only under the professional supervision of a licensed veterinarian.


A VCPR is required for all Extra-Label Drug Use, consult with your herd veterinarian to establish a VCPR.