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As the Food and Drug Administration (FDA) changes food-producing animal drug labels to better clarify the indications and directions, they often change the verbiage and specific species details. Below are some questions we here at FARAD have asked ourselves. We share our answers with you in order to assist you to better utilize our website, especially VetGRAM.

In the metric system, 1000 milligrams (mg) is a unit of mass equal to 1 gram and 1000 micrograms (mcg) is equal to 1 milligram (mg). An IU (International Unit) is a unit of measurement for vitamins and other specific biologically active substances. The precise measure of one IU differs from substance to substance and is established by international agreement for each substance. For example, vitamin E exists in a number of different forms having different biological activities. Rather than specifying the precise type and mass of vitamin E in a preparation, the Supplement Facts label summarizes the biological activity of the forms present as the number of International Units of vitamin E.
Type A medicated article is a new animal drug, with or without carrier (e.g., calcium carbonate, rice hull, corn, gluten) or inactive ingredients, intended solely for use in the manufacture of another Type A medicated article or a Type B or Type C medicated feed.
Type B medicated feed is used for further mixing, and cannot be fed. It contains a substantial quantity of nutrients, originates from a Type A medicated article or a Type B feed and is intended solely for the manufacture of other Type B or Type C medicated feeds.
Type C medicated feed contains a new animals drugs and is intended as the complete feed for the animal or may be fed “top dressed” (added on top of usual ration) on or offered “free-choice” (e.g., supplement) in conjunction with other animal feed. It contains a substantial quantity of nutrients including vitamins, minerals, and/or other nutritional ingredients. The manufacture of a Type C medicated feed requires a medicated feed mill license.
New animal drugs approved for use in animal feed are placed in two categories as follows:
Category I: Drugs that require no withdrawal periods at the lowest approved use level.
Category II: Drugs that do require a withdrawal period at the lowest approved use level; have no residue or a "zero" tolerance. [source]
A combination drug is defined as an approved combination of new animal drugs intended for use in or on animal feed under the supervision of a licensed veterinarian. At least one of the new animal drugs in the combination is a VFD drug. View approved VFD drug combinations.
The FDA defines drug compounding as the process of combining, mixing, or altering ingredients to create a medication tailored to the needs of an individual patient. Compounding includes the combining of two or more drugs and are not FDA-approved. Read more about compounding in our PDF.
Not really. They all deliver a dose of a medication over an extended period of time.
Prolonged-release tablets and capsules are aimed at delaying administration and dissolve at a slower, but not a specific rate or concentration, into the system with the benefit of not having to take the drugs more frequently.
Sustained-release tablets are more of a controlled release. Their aim is to maintain a certain concentration of the drug over a specific period of time.
An extended-release drugs is delivered even more slowly than sustained-release so they may have a slightly slower onset, but may mean better treatment outcomes for longer periods of time.
A drug concerned specifically with the treatment, control, removal, or reduction of disease, including parasitic diseases. The therapeutic dose of a drug is the amount needed to treat a disease.
No. Although both require a written order from a Veterinarian, a veterinary feed directive is specifically required for a drug added to a feed.
Drenching is the act of administering oral medications in liquid form into the back of the mouth using a syringe or a device called a 'drenching gun'.
A withdrawal time of N/V, means no value of any kind was mentioned or implied in the FOI or Greenbook, at the time the drug was entered in our database.
A WDT of Zero means within the FOI it was stated that "a zero-day pre-slaughter withdrawal period is required", "No withdrawal period is required.", or the like.
A withdrawal time, or WT or WDT, is the period following the administration of an FDA-approved animal drug, in accordance with label guidelines, for which the animal and its products must be withheld from food production.
A withdrawal interval, or WDI, provided by FARAD, is the time following extra-label drug use (ELDU) until drug concentrations in tissues or animal-derived products are estimated to fall below the FDA tolerance. If there is no tolerance established then the interval will be the time following, until drug concentrations in tissues or animal-derived products have reached undetectable concentrations.
OTC: Available over the counter, and without a prescription.
VFD: A Veterinary Feed Directive is a written statement from a licensed veterinarian that authorizes a client to obtain and use a VFD drug in or on animal feed.
Rx: A medical prescription written by a licensed veterinarian, that authorizes a client to dispense the medicine as directed.
Rx(CA): A drug that the FDA has given a status of OTC, but in the State of California, a prescription is required.
Trade dress refers to how the drug package actually looks, as in shape and color, material such plastic or cardboard, etc.
Gilts: young female pigs that have not farrowed a litter and are intended for slaughter or breeding purposes.
Sows: are females that have already had one litter.
Boars: are intact males usually used for breeding.
Barrows: are males that have been castrated and usually become market hogs.
The stage that comes after lactation (after the weaning event), in which the piglets are taken away from their dam and normally proceed to eat only solid food (compound feed) and water. It normally lasts 7-8 weeks and the piglets can grow approximately 20-25 kg during this stage.
Yes, pre or non-ruminating and suckling calves do not have the capacity to digest fiber are dependent upon their dam. They do not have a fully developed rumen. The rumen houses many tiny organisms which aid in the digestion of food such as hay and grass. Pre or non-ruminating and suckling calves are not the same as veal calves, who are no longer dependent upon their dam, but still may not have a functioning rumen based on their diet.
Veal is the meat of calves, in contrast to the beef from older cattle. Veal can be produced from a calf (no longer dependent on its dam) of either sex and any breed; however, most veal comes from young males of dairy breeds which are not used for breeding, whereas most female dairy calves are kept to replace older cows used in the cycle of milk production.
Milk-fed (aka formula-fed) veal: These calves are fed nutritionally-balanced milk or soy-based diets. These specially-controlled diets contain iron and other essential nutrients. These calves are marketed at about 500 pounds and six months of age.
Pasture-raised veal: These calves are fed a variety of diets, including milk replacer, grain and forages (hay, silage, or pasture). They are marketed at live weights of 151 to 400 pounds.
Bob veal: These calves are marketed through sale barns or directly from dairy farmers after birth and up to three weeks of age, or a weight of less than 150 pounds.
ANIMAL DRUGS - Dairy Cattle
Lactating: dairy are producing milk. The production of milk requires that the cow be in lactation, which is a result of the cow having given birth to a calf.
Dry: dairy have previously produced milk for human consumption and will do so again in the future after completion of the dry period between lactations.
Non-lactating: dairy have not or never will produce milk for human consumption. The term non-lactating dairy cattle does not include dry dairy cows.
Technically, no. Heifers can become pregnant as soon as they reach puberty, which is influenced by weight and breed. However, any drugs approved under under these restrictions are not to be used in milk producers (lactating dairy). See NADA 141-095 Dectomax® Pour-on Solution for Cattle
Specifically, dairy pasture cattle are non-lactating dairy cattle that include replacement dairy heifers, replacement dairy bulls, and dairy calves, that will never produce milk for human consumption.
An animal that suckles its young, especially a cow that is kept to feed its own young, raised for beef.
All of these cattle (the broad spectrum plural without regard to sex) can be of the dairy or beef breed.
Cow: A cow is a female bovine that has had at least one calf. Cows have very developed udders for milk production.
Heifer: A heifer is a female bovine that has never had a calf, and has no prominent udders. Once she gives birth, she automatically becomes a cow.
Steer: A steer is a male animal that has been neutered and is suited for meat production.
Bull: A mature male animal that is used for breeding.
The time it takes for a heifer to reach puberty depends on her weight and breed. Even though the early maturing breeds do reach puberty by the time they are 7 to 9 months of age, breeders usually prefer their heifers to become pregnant around 15 months of age so that they give birth when they are about two years old.
The FDA often puts restrictions on species, such as "breeding" or "lactating", or adds a warning such as "not for use in laying hens" or "do not use in veal calves". The term "all use classes" means the FDA has not yet restricted this drug in any sub group of the species listed.
Pyometra is a uterine infection. Though it is most commonly known as a disease of the unaltered female dog, it is also notable in bovine (and other mammals?).
Also known as "Udder edema" and is generally a periparturient (around the time of birth) disorder characterized by excessive accumulation of fluids in the intercellular tissue spaces of the mammary gland. Incidence and severity are greater in pregnant heifers than in cows.
Estrus refers a recurring period of sexual receptivity and fertility in many female mammals; heat.
Postpartum estrus refers to the period following the birth of young.
Pubertal estrus refers to the period during which adolescents reach sexual maturity and become capable of reproduction.
Slaughter cattle, stocker cattle, feeder cattle, and replacement beef or dairy heifers and all considered "Pasture cattle" and exclude pre-ruminating calves, veal calves and lactating dairy cattle. These cows will stay on pasture eating grass for their entire lives.
Steers, heifers and/or bulls (including dairy breeds), intended for slaughter and fed in confinement. Most of the beef consumed in the United States comes from feedlots, where cattle arrive after living for six months on pasture and grass to be finished for another six months or so on a diet of corn and other grains. Feedlot cattle exclude pre-ruminating calves, veal calves and lactating dairy cattle.
Also known as replacement breeders or caged-layers. These replacement chicken are mature male or female chickens intended for the production of fertile eggs where eggs are not intended for human consumption.
Chickens that are bred and raised specifically for meat production. The term "broiler" is mostly used for a young chicken, 6 to 10 weeks old, and is interchangeable and sometimes in conjunction with the term "fryer."
Mature chicken that produce eggs for human consumption.
Replacement chickens are generally known as a grower chicken; intended to become laying hens or breeding chicken. The term "replacement" means pullets that will be replacing older hens destined to be removed at the end of their laying cycle of eggs for human consumption.
Hens are female and Toms are male. Hens mature in 16 weeks and range from 8-16lbs on average, but if a hen reaches the 24lb range, a hen will develop a fat layer, which flavors the bird while roasting. Toms mature at 19 weeks and generally range from 18-24lbs. Most supermarket birds are Toms.
Turkeys take up more space and cost more to feed then chicken. Turkey's do not lay eggs nearly as often. A fertilized turkey egg is much more valuable than an egg for human consumption.
This class includes Pacific, Atlantic, and freshwater-reared salmon, trout, char, and whitefish. Some salmonids spend their entire life in freshwater, others spend most of their life in the sea and swim up rivers and streams to spawn.
No. All finfish are fish, however according to the FDA, "fish" include freshwater and saltwater finfish, as well as shellfish, crustaceans, amphibians, and jellyfish.
Rearing, also known as fish farming, is the breeding, raising, and harvesting of fish, shellfish, algae, and other organisms in all types of water environments. There are two main types of fish farming - marine and freshwater. Marine aquaculture produces numerous species including oysters, clams, mussels, shrimp, salmon, black sea bass, yellowtail, and pompano. Freshwater aquaculture produces species such as catfish and trout. Freshwater fish farming primarily takes place in ponds, tanks or other manmade enclosures.
Recently hatched fish that have developed to the point where they are capable of feeding themselves, are called fry. When, they have developed scales and working fins, the transition to a juvenile fish is complete and it is called a fingerling. Fingerlings are typically about the size of fingers, ranging in weight from 1 to 25 g or from 2.5 to 10 cm in total length. Source
Tolerance Definitions CFR 556.3
Tolerance means the maximum concentration of a marker residue, or other residue indicated for monitoring, that can legally remain in a specific edible tissue of a treated animal.
The ADI is a measure of the amount of a specific substance (a residue of a veterinary drug or pesticide) in food or drinking water that can be ingested on a daily basis over a lifetime without an appreciable health risk. ADIs are expressed usually in mg per kg of body weight per day.
Target tissue means the edible tissue selected to monitor for residues in the target animals.
Marker residue means the residue whose concentration is in a known relationship to the concentration of total residue in an edible tissue.
If a tolerance value is "Not required", it means that at the time of approval:
(1) No withdrawal period was necessary for residues of the drug to deplete to or below the concentrations considered to be safe, or an adequate withdrawal period was inherent in the proposed drug use, and there was a rapid depletion of residues, so there was no concern about residues resulting from misuse or overdosing; or
(2) No withdrawal period was necessary because the drug was poorly absorbed or metabolized rapidly so as to make selection of an analyte impractical or impossible.
A tolerance of "Zero" means any residues detected in the tissue renders it unsafe.