Residues

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Drugs


Introduction video

Drugs

When dairy animals get sick and need treatment, producers and veterinarians may prescribe antibiotics and other drugs. These drugs must be used judiciously to prevent residues from occurring in milk or dairy beef sent to market. The marketing of milk or meat with antibiotic residues is illegal and can result in financial and criminal penalties. 

Penalties video

A large variety of drugs have been approved or can be extra labeled for lactating dairy cows. There are three classes of animal drugs:

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

·         Prescription (RX): These can only be sold to the public by a veterinarian or pharmacist, and only with a written prescription of a veterinarian.

·         Veterinary Feed Directive (VFD): A drug intended for use in or on feed, which is limited by an approved application to use under the professional supervision of a licensed veterinarian.  The Food and Drug Administration oversees this program, and the full document can be found at: http://www.fda.gov/AnimalVeterinary/DevelopmentApprovalProcess/ucm071807.htm


Drugs will be administered by one or more routes, depending on the nature of the drug, and the condition being treated or prevented. Commonly used routes include:

·         Medicated feed. The Association of American Feed Control Officials defines medicated feed as "any feed which contains drug ingredients intended or presented for the cure, mitigation, treatment, or prevention of disease in animals other than man or which contains drug ingredients intended to affect the structure or any function of the body of animals other than man". A brief summary of the Federal Food, Drug, and Cosmetic Act can be found at: http://www.fda.gov/downloads/ForConsumers/.../UCM171028.pdf

·         Intramuscular injection. An intramuscular injection is an injection given directly into the central area of a specific muscle. This allows the blood vessels supplying that muscle to distribute the injected medication via the cardiovascular system. The proper method of administering drugs by intramuscular injection is shown in a video that can be found at: http://bqa.org/bqainjectionsitedemo.aspx

·         Intravenous injection. This refers to administration of medication directly into a vein. This initiates a rapid systemic response to the medication. In general, drugs administered intravenously have a shorter time to onset of action. It is also easier to maintain drug levels in the blood for therapeutic response.

·     Subcutaneous injection. This refers to administration of medication just under the skin, but not into the muscle tissue (subcutis). The preferred location to perform a subcutaneous injection is on the side of the neck. If the product is labeled for either intramuscular or subcutaneous, the subcutaneous route is preferred since there is less risk of causing lesions within the carcass.

·         Intrauterine infusion. This is used primarily for treating conditions of the female reproductive tract and involves the deposition of medication directly into the uterus. The drugs may be deposited via pipette if the cervix is partially or completely closed.

·         Intramammary infusion. Treatment of intramammary infections (mastitis) often involves use of intramammary infusions.  With this method, the drug is suspended in a liquid and delivered directly into the mammary gland via the teat canal. The proper method of performing this treatment method is described here at this website

All animal medications come with warning labels. Warning labels address the required length of time that the cow’s milk is to be withdrawn following completion of drug treatment. Milk from treated cows must not be used for food during treatment and withdrawal period. Withdrawal times are specific to each drug and based on the number of milkings. The FDA has established guidelines for uniform labeling of drugs for cattle, which can be found at this link.

Drugs and Related Laws video

Classification of veterinary drugs

There are a number of possible methods to classify drugs used in veterinary medicine. Here, the approach utilized by the Merck Veterinary Manual is presented.

Antibacterial agents

This broad category can be further divided, based on chemistry, mechanism of action, and other features into:

                Penicillins: Several subclassifications of the penicillins exist, based mainly on differences in antibacterial spectra, are recognized, but all contain a ß-lactam nucleus. Examples include penicillin V, oxacillin, cloxacillin, ampicillin, amoxicillin, carbenicillin, ticarcillin, imipenem, and many others. These drugs impair the development of bacterial cell walls by interfering with certain enzymes.

                Cephalosproins and cephamycins: These are similar to penicillins (are a class of ß-lactam antibiotics), but are more stable to pH and temperature changes. Their mode of action is similar to that of the penicillins. Ceftiofur is an important veterinary medical example of this class of antibacterial agent.

                Aminoglycosides: Veterinary examples of importance in this class include gentamicin, neomycin, and streptomycin. Their mode of action is through interference with protein synthesis within the membrane-associated bacterial ribosome. One feature of this family is that they tend to accumulate in the renal cortex.

                Quinolones: These drugs are derived from several closely related ring structures that have certain common features. Examples of veterinary importance include enrofloxacin, ciprofloxacin, danofloxacin, and nalidixic acid. The quinolones inhibit the bacterial enzyme DNA-gyrase, resulting in a disruption of the spatial arrnagment of DNA.

                Sulfonamides and sulfonamide combinations: Sulfonamides remain among the most widely used antibacterial agents in veterinary medicine because of their relative low cost and efficacy in some common bacterial diseases. All are derivatives of sulfanilamide, with various functional groups attached to the common nucleus. There are many sulfonamides, some of interest in food-production include sulfathiazole, sulfamethazine, sulfamerazine, sulfadizine, sulfadimethoxine, and sulfisoxazole. These drugs are analogs of para-aminobenzoic acid (PABA), and interfere with production of folic acid which eventually block several enzymes, resulting in suppression of protein synthesis.

                Tetracyclines: This is a family of broad-spectrum antibiotics, including oxytetracyline, chlortetracycline, tetracycline, doxycycline and others. They act by binding to bacterial 30 S ribosomes and inhibit protein synthesis.

                Chloramphenicol and congeners: While used in companian animals, chloramphenicol is prohibited for use in food-producing animals in several countries, including the USA and Canada. Florfenicol is a related chemical that does not have the deleterious side effects associated with chloramphenicol, and is an important drug for food-producing animals. These compounds act by impairing peptidyl transferase activity.

                Macrolides: Macrolides are characterized by having a large lactone ring in their structure. Examples include erythromycin, gamithromycin, spiramycin, tildipirosin, tulathromycin, and tylosin.  These drugs interfere with protein synthesis by reversibly binding to the 50 S subunit of the ribosome.

                Lincosamides: Lincomycin and clindamycin also bind to the 50 S subunit of bacterial ribosomes and suppress protein synthesis.

                Miscellaneous antimicrobial agents: A number of antimicrobial agents are used periodically for several diverse purposes. Some examples important in food-producing animals include novobiocin (used in mastitis treatment), tiamulin (used to treat swine dysentery), nitrofurans (not allowed in food-producing animals), and nitroimidazoles (not allowed in food-producing animals).

Antifungal agents: Fungal infections can occur topically (skin or mucous membranes) or systemically. A number of antifungal agents are available, including amphotericin B, nystatin, the imidazoles (e.g., thiabendazole, clotrimazole, ketoconazole), flucytosine, griseofulvin, and sodium and potassium iodide.  

Antivral agents and Biologic response modifiers: Drugs that target viral processes must penetrate host cells, and in so doing, they are likely to disrupt normal pathways of the host. Only a few agents have been found to be reasonably safe and effective and most of these have been developed in humans. Widespread use in veterinary medicine is not common. Included in this group are ribavarin, azidothymidine (AZT), and amantadine.

Anthelmintics: There are several classes of anthelmintics, including benzimidazoles, salicylanilides, imidazothiazoles, organophosphates, and macrocyclic lactones (avermectins and milbemycins). The two primary modes of action are 1) impairment of cell structure, integrity or metabolism, and 2) disruption of neuromuscular coordination. A few examples of importance in food-producing animals include albendazole, fenbendazole, febantel, levamisole, tetramisole, pyrantel, dichlorvos, piperazine, clorsulon, ivermectin, doramectin, and eprinomectin. All these compounds must be used correctly and judiciously to obtain a favorable response, accomplish good control, and minizme selection for anthelmintic resistance.

Anti-inflammatory agents: Inflammation is a complex response of tissue to injury, and is characterized by one or more of 5 symptoms, namely heat, redness, swelling, pain, and loss of function. Occassionaly, veterinarians will administer anti-inflammatory agents to reduce the negative effects of excessive inflammation, and restore function as quickly as possible. For example, antihistamines are used to counter immediate hypersensitvity reactions and other allergic reactions such as atopy. Corticosteroids such as prednisone and dexamethasone, are commonly used for their anti-inflammatory effects, as well as for their effects on carbohydrate, protein, and lipid metabolism. Nonsteroidal anti-inflammatory (NSAID) drugs are important for use in both pain management and control of inflammation. Unlike corticosteroids, which inhibit numerous pathways, NSAIDS act primarily to reduce the biosynthesis of prostaglandins (PG) by inhibiting cyclooxygenase (COX). Some examples of important NSAIDS are aspirin, phenylbutazone, carprofen, meloxicam, acetaminophen, ibuprofen, and flunixin meglumine.

Antiseptics and disinfectants: These are nonselective, anti-infective agents that are applied topically to reduce the number of microorganisms (sanitization) or destroy all microbes (sterilization) on the applied surface. Most of these compounds exert their antimicrobial effect by denaturation of intracellular protein, alteration of cellular membranes, or enzyme inhibition. This category can be divided into several subclasses, including acids and alkalies, alcohols, biguanides, oxidizing agents, metals, phenols and related compounds, reducing agents, surface-active compounds (surfactants), and vapor-phase disinfectants.

Ectoparasiticides: Treatment with various drugs to reduce or eliminate arthropod parasites is often required to maintain health and to prevent economic loss in food animals. This group includes organophosphates and carbamates, pyrethrins and synthetic pyrethroids, macrocyclic lactones, formamidines, spinosyns, and insect growth regulators. Products are available for both parenteral and for topical application, with the method used depending on the target parasite and host. Accurate diagnosis is necessarty for selection of the appropriate drug.

Growth promotants and production enhancers: Increased efficiency of production is an important goal of livestock producers. Two of the most practical approaches are hormonal treatments (steroid hormones, growth hormone, ß-adrenoceptor agonists) and antimicrobial feed additives (ionophore antibiotics, nonionophore antibiotics, probiotics).

Vaccines and immunotherapeutics: Vaccines can provoke effective, longterm immunity and thereby protect against infection with microbial agents. In addition, some microbial molecules can stimulate the development of innate immune responses and this nonspecific immunostimulation may enhance resistance to infection. 


Antibiotics are of special interest to the dairy industry, due to concern over the presence of antibiotic residues in meat and milk and the possible association with use of antibiotics in animals and the development of drug-resistant bacterial infections that may be transferred to humans. A definition of an antibiotic is: A chemical substance or compound that kills or reduces the growth of susceptible bacteria. Antibiotics are a type of antimicrobial, but not all antimicrobials are antibiotics (e.g. anti-viral drugs and anti-fungal drugs are antimicrobials but are not antibiotics).

The American Veterinary Medical Association has a policy for the Judicious Therapeutic Use of Antimicrobials, part of which reads: “When the decision is reached to use antimicrobials for therapy, veterinarians should strive to optimize therapeutic efficacy and minimize resistance to antimicrobials to protect public and animal health”. The entire document can be found on the AVMA website at: http://www.avma.org/issues/policy/jtua.asp

 

Extra-label drug use (ELDU)

OTC, Rx, and Extra-label Use video

Any use of a drug not specifically listed on the label is called “extra-label drug use”. This is carefully regulated by the FDA under the Animal Medicinal Drug Use Clarification Act (AMDUCA) of 1994. Under this act, using a prescription or over-the-counter drug in an extra-label manner is illegal unless it is specifically recommended under the guidance of a veterinarian working in the context of a Veterinary-Client-Patient Relationship (VCPR). There are no legal extra-label uses of Veterinary Feed Directive drugs.

Drug Management Program video

Some examples of extra-label drug use include:

       Changing the dose administered

       Changing the route of administration

       Changing the frequency of use

       Giving the drug to a different production class of animal

       Giving the drug for an indication (disease) not listed on the label

       Changing the withholding times

       Changing the amount of drug per injection site

       Changing the duration of therapy

 

Record keeping for ELDU: FDA 21CFR 530.5 mandates that veterinarians maintain records for two years of all animals treated using extra-label drugs

       Identify the animals, either as individuals or a group

       Name of drug and active ingredient

       Condition treated

       Species of treated animal

       Dose administered

       Duration of treatment

       Numbers of animals treated

       Specified withdrawal, withholding, or discard times

 

Labels for ELDU must include the following information:

       Name and address of prescribing veterinarian

       Established name of the drug

       Any specified directions for use including the class/species or identification of the animal or herd, flock, pen, lot, or other group; the dosage frequency, and route of administration, and the duration of therapy

       Any cautionary statements

       Specified withdrawal, withholding, or discard time for meat, milk, eggs, or any other food

An example of an acceptable label is shown below. 

The American Veterinay Medical Association has created an algorithm that veterinarians and their clients can use to determine whether it is appropriate to use a drug in an extralabel manner. The algorithm can be found at this link:

Reasons for Management Plan video

There are many drugs that are strictly prohibited for extralabel use in food animal species. Included on the list are:

       Chloramphenicol

       Clenbuterol

       Diethylstilbestrol (DES)

       Dimetridazole

       Ipronidazole

       Other Nitroimidazoles

       Furazolidone, Nitrofurazone, Other Nitrofurans

       Sulfonamide drugs in lactating dairy cows (except approved use of sulfadimethoxine, sulfabromomethazine, and sulfaethoxypyridazine)

       Flouroquinolones

       Glycopeptides (example vancomycin)

       Phenylbutazone in female dairy cattle 20 months of age or older

       Adamantane and neuraminidase inhibitor classes of drugs that are approved for treating or preventing influenza A are prohibited therapy in chickens, turkeys, and ducks.

       Cephalosporin drugs (not including cepharin) in cattle, swine, chickens, and turkeys (effective April 5, 2012). The following uses are prohibited:

       Using cephalosporin drugs at unapproved dose levels, frequencies, durations or routes of administration

       Using cephalosporin drugs in cattle, swine, chickens, or turkeys that are not approved for use in that species

       Using cephalosporin drugs for disease prevention

       The following exceptions to the prohibition apply:

       Extralabel use of approved cepharin products in food-producing animals

       Use to treat or control an extralabel disease indication, as long as this use adheres to a labeled dosage regimen (i.e. dose, route, frequency, and duration of administration) approved for that particular species and production class

       Extralabel use in food-producing minor species, such as ducks or rabbits

  Drugs with No Extra-label Use video

Always check the FDA website (specifically, 21 CFR Sec. 530.41 in the Code of Federal Regulations) for updates, as this list may change.

 

The Pasteurized Milk Ordinance stipulates that all bulk milk tankers be sampled and analyzed for beta-lactam drug residues before the milk is processed. Any tanker found positive for beta-lactam residue is rejected for human consumption. In 2011, 671 of over 3.1 million tanker loads of milk (0.021%) tested positive for drug residues. Other drug residues are screened for through a random sampling program. The United States Department of Agriculture Food Safety Inspection Service (USDA FSIS) conducts tests for chemicals (including antibiotics, pesticides, and various other drugs) in meat, poultry and egg products destined for human consumption.

  

Dairy cattle diseases

  

Dairy cattle diseases and common treatments

The objective of this section is to enable you to understand the most common dairy cattle diseases, know the types of drugs used to treat these conditions, common causes of drug residues, and prevention strategies to avoid violative residues. Recognize that this is a very short list of the most common conditions that may be encountered on a dairy farm.

A.      Diseases of calves

·         Dystocia, which is defined as an abnormal or difficult birth or labor. This is the leading cause of calf death at or shortly after birth. The most common cause of dystocia is that the calf is too large to be delivered normally. Other causes include multiple births (twins) and malpresentation of the calf (backwards, foot back, breech, etc.)

Dystocia adversely affects the cow. She will be at increased risk of uterine infections, retained placenta, and having a longer calving interval than cows that do not experience dystocia.

Dairies need to provide a clean, dry, well-ventilated space for the maternity area. Cows must be observed closely when they are close to calving, and assistance provided when necessary.

·         Scours, or abnormally loose stool or diarrhea.  The basic physiologic effect is fluid and electrolyte loss, which results in dehydration and sometimes death. Survivors will often remain weak and perform poorly throughout their lives.

Causes of scours are usually divided into infectious and non-infectious causes. There are a number of bacteria, viruses and protozoa that have been associated with scours. Non-infectious causes are usually the result of inappropriate feed or feed mixture for the age of the calf, or sudden changes in feed.

Prevention of this condition relies on minimizing pathogen challenge by improving housing, maximizing colostrum quality and quantity, ensuring proper nutrition, and avoiding overstocking and mixing groups of animals.

Treatment of scours should focus on fluid replacement, either oral, subcutaneous, or intravenous administration of balanced electrolyte solutions. In addition, nursing care (providing a warm, dry environment and good nutrition) is very important. Although many of the causative agents are not susceptible to antibiotics, antibiotics are often administered to prevent secondary complications, such as bacteremia and septicemia.

·         Pneumonia, or inflammation of the lungs, is frequently, but not always, due to infection which may be bacterial, viral, fungal, or parasitic. This is a multifactorial condition, involving interactions of infectious agents, environment, management and the immune status of the calf. Animals that survive pneumonia may have reduced weight gain, calve later, and produce less milk than non-affected herdmates.

Prevention of pneumonia relies on ensuring proper nutrition and adequate colostrum intake. Vaccines are available against the most common causes which can aid in prevention of the disease. Environmental management is critical – clean, dry bedding must be provided, hutches and pens must be santized between calves.

Treatment usually involves use of antibiotics (oral, intravenous, intramuscular, or subcutaneous), and often anti-inflammatory agents are also administered. Again, nursing care (warm, dry environment, good nutrition, prevent other illnesses) is critical to obtaining a positive response to therapy.

B.      Diseases of heifers

·         Pneumonia in heifers is often very similar to the disease in calves (see above). This is a multifactorial condition, involving interactions of infectious agents, environment, management and the immune status of the calf. Pneumonia is especially important in heifers, as those that survive may have reduced weight gain, calve later, and produce less milk than non-affected herdmates.

Prevention of pneumonia relies on ensuring proper nutrition and adequate colostrum intake. Vaccines are available against the most common causes which can aid in prevention of the disease. Environmental management is critical – clean, dry bedding must be provided, hutches and pens must be santized between calves.

Treatment usually involves use of antibiotics (oral, intravenous, intramuscular, or subcutaneous), and often anti-inflammatory agents are also administered. Again, nursing care (warm, dry environment, good nutrition, prevent other illnesses) is critical to obtaining a positive response to therapy.

·         Injury is relatively common in growing heifers. They are inquisitive, which can result in a wide variety of injuries. Specific treatment will depend on the location of the injury and the severity of the involved area. For example, an open wound resulting from a cut will usually be bandaged, and may involve administration of local and/or systemic antibiotics and antiinflammatory agents.

·         Bloat, scours, other digestive problems. Heifers are often consume considerable amounts of feed, which can predispose them to a variety of gastrointestinal conditions.

Bloat is a digestive disorder characterized by an accumulation of gas in the first two compartments of a ruminant's stomach (the rumen and reticulum). Production of gas (primarily carbon dioxide and methane) is a normal result of fermentation processes. The gas is usually discharged by belching (eructation) but, if the animal is unable to remove the excess gas, pressure builds up in the rumen-reticulum exerting pressure on the diaphragm which prevents the animal from inhaling, and bloat occurs. The most common type of bloat is frothy bloat where gas builds up in a foam or froth above the liquid/semi-liquid fraction of the rumen content and the normal belching is inhibited. Bloat, if severe, can cause death due to restricted breathing and heart failure. Treatment usually involves passing a tube into the rumen providing a mechanical release of gas, administration of oil or other antifoaming agents such as dioctyl sodium sulfosuccinate (which reduces surface tension and allows gas to escape), or in very severe cases, an emergency rumenotomy may be performed.

C.      Diseases of cows

·         Mastitis (contagious, environmental)

Mastitis is a general term that refers to persistent inflammation of the udder tissue. White blood cells are released into the mammary gland, usually in response to an invasion of bacteria of the teat canal, but can also occur as a result of chemical, mechanical, or thermal injury. Abnormalities in the udder may include swelling, heat, redness, hardness or pain. Abnormalities in milk, such as a watery appearance, flakes, clots, or pus, are also common. 

Causes of mastitis are often divided into contagious (spread from cow to cow) and environmental (infection obtained from the cow's bedding, ponds, mud, etc.). Control of contagious mastitis focuses on milking hygiene and separation of infected cows from non-infected, while environmental mastitis control focuses on maintaining a clean cow in a clean environment. 

Usually, mastitis is treated with antibiotics, both systemic (intramuscular, subcutaneous, or intravenous) and intramammary. Severe cases may require intravenous or oral fluids and antiinflammatory drugs as well.

·         Lameness

Foot and leg problems are a major health concern for many dairy farmers. Nutrition and feeding, housing, and environment, concurrent disease, genetic influences, and management factors all predispose a cow to problems. Most lameness involves the foot, and most of these involve the rear feet. The most common causes of lameness are laminitis, claw disease, digital dermatitis, and foot rot. 

Cases amenable to antibiotic treatment, such as digital dermatitis and foot rot, are treated with systemic antibiotic therapy. A fairly large proportion of cases are removed from the herd (culled) due to poor prognosis for complete recovery.

·         Infertility (not pregnant 150 days after calving)

If the cow does not become pregnant, she may be administered various reproductive hormones, in  an attempt to improve the probability of conception. Chronic infertility will result in the cow being culled (since delivering a calf is important for obtaining the greatest milk production).

·         Metabolic (e.g. milk fever, ketosis)

This refers to diseases related to disturbance of one or more metabolic processes in the cow. The "transition period" (includes three weeks before and three weeks after parturition) is very critical for dairy cows. During this period, the cow is undergoing hormonal changes, moving from a non-lactating to a lactating state, and switching from a roughage-based diet (hay and grass) to a diet rich in rapidly fermentable carbohydrates (high-grain diets). A few of the most common metabolic disorders include 1) ruminal acidosis (increased production of acid in the rumen, and low rumen pH), 2) ketosis (increased ketone bodies in the blood), 3) milk fever (decreased blood calcium due to excretion in the milk), 4) left displaced abomasum, 5) laminitis, 6) fatty liver, and 7) bloat

Treatment will depend on the exact metabolic condition, but options include intravenous administration of glucose, calcium, magnesium, oral electrolytes, and propylene glycol. Surgery may be required for some conditions, which may result in administration of antibiotics to prevent secondary infections.

·         Reproductive (metritis, retained fetal membranes)

Treatments usually involve administration of various antibiotics by one of several possible routes, including intravenous, intramuscular, subcutaneous, oral, and in utero.

·         Low production

Associated with a number of possible factors (poor nutrition, inadequate genetic potential, chronic disease, etc), “treatment” often means culling.

Routes of Administration video


FDA-approved drugs for dairy cattle

FDA Approved drugs for dairy cattle

The following tables have been reproduced from a manual produced by the National Milk Producers Federation titled “Milk and Dairy Beef Drug Residue Prevention. Producer Manual of Best Management Practices, 2013”. Further information was obtained from the website, "Animal Drugs @ FDA".

FDA-Approved Drugs for injectable use in Non-lactating cattle*

 

Active ingredient

Drug type

Meat withholding time

Ampicillin trihydrate

Rx

6 days

Ceftiofur crystalline free acid

Rx

13 days

Ceftiofur hydrochloride

Rx

3 days

Ceftiofur sodium

Rx

4 days

Cloprostenol sodium

Rx

None

Dinoprost tromethamine

Rx

None

Doramectin

OTC

35 days

Erythromycin

Rx

21 days

Florfenicol

Rx

28 or 38 days**

Florfenicol and flunixin meglumine

Rx

38 days

Flunixin meglumine

Rx

4 days

Gonadotropin (chorionic)

Rx

None

Gonadorelin diacetate tetrahydrate

Rx

None

Gonadorelin hydrochloride

Rx

None

Isoflupredone acetate

Rx

7 days

Ivermectin***

OTC

35 days

Ivermectin/Chlorsulon***

OTC

49 days

Oxytetracycline

OTC

28 days

Oxytetracycline hydrochloride

Rx or OTC

18 or 22 days**

Penicillin G (benzathine)

OTC

30 days

Penicillin G (procaine)

OTC

4 to 14 days**

Selenium (sodium selenite)

OTC

30 days

Spectinomycin sulfate

Rx

11 days

Sulfachlorpyridazine (sodium)

OTC

5 days

Sulfadimethoxine

OTC

5 days

Tilmicosin phosphate*

Rx

42 days

Tripelennamine HCL

Rx

4 days

Tulathromycin

Rx

18 days

Tylosin

OTC

21 days

Vitamin E

OTC

None

 

                *The term non-lactating cattle is defined as including dairy bulls, dairy calves, and replacement heifers. Read the label indications carefully. Some products are not approved for non-ruminating calves and female dairy cattle 20 months of age and older. Some products cannot be used with veal calves. Carefully consult the labels.

                **Withholding times depend upon manufacturer or labeled dosage used. Carefully consult the labels.

                ***Ivermectin is not approved for female dairy cattle of breeding age.

 

FDA-Approved Drugs for intramammary use** in Non-lactating cattle*

Active ingredient

Drug type

Milk withholding time

Meat withholding time

Ceftiofur hydrochloride

Rx

None

16 days

30 days dry cow

Cephapirin (benzathine)

OTC

72 hours

42 days

Cloxacillin (benzathine)

Rx

None

28 or 30 days***

Novobiocin

OTC

72 hours post-calving

30 days

Penicillin G (procaine)

OTC

72 hours post-calving

14 days

Penicillin G (procaine)/

Dihydrostreptomycin

Rx

96 hours post-calving

60 days

Penicillin G (procaine)/

Novobiocin

OTC

72 hours post-calving

30 days

*The term non-lactating cattle is defined as including dairy bulls, dairy calves, and replacement heifers. Read the label indications carefully. Some products are not approved for non-ruminating calves and female dairy cattle 20 months of age and older. Some products cannot be used with veal calves. Carefully consult the labels.

**Do not use within 4 weeks (28 days) of calving.

***Withholding times depend upon manufacturer or labeled dosage used. Carefully consult the labels.

 

 

FDA-Approved Drugs for oral use in Non-lactating cattle*

 

Active ingredient

Drug type

Meat withholding time

Albendazole

OTC

27 days

Amprolium

OTC

1 day

Chlortetracycline hydrochloride

OTC

1 day

Citric Acid

OTC

None

Decoquinate

OTC

None

Dextrose

OTC

None

Fenbendazole

OTC or Rx

8 days

Glycine

OTC

None

Lasalocid

OTC

None

Levamisole hydrochloride

OTC

2 days

Monensin (sodium)

OTC

None

Neomycin sulfate

OTC

1 day

Oxfendazole

OTC

7 days

Oxytetracycline dinydrate

OTC

5 days

Oxytetracycline hydrochloride

OTC

None to 7 days**

Potassium citrate

OTC

None

Potassium dihydrogen phosphate

OTC

None

Sodium chloride

OTC

None

Streptomycin sulfate

OTC

2 days

Sulfachlorpyridazine (sodium)

OTC

7 days

Sulfadimethoxine

OTC

7 or 12 days**

Sulfamethazine

OTC

10 or 12 days**

Sulfamethazine (sodium)

OTC

10 days

Sulfaquinoxaline (sodium)

OTC

10 days

Tetracycline hydrochloride

OTC

4 to 7 days**

 

*The term non-lactating cattle is defined as including dairy bulls, dairy calves, and replacement heifers. Read the label indications carefully. Some products are not approved for non-ruminating calves and female dairy cattle 20 months of age and older. Some products cannot be used with veal calves. Carefully consult the labels.

** Withholding times depend upon manufacturer or labeled dosage used. Carefully consult the labels.

 

 

FDA-Approved Drugs for topical use in Non-lactating cattle*

Active ingredient

Drug type

Meat withholding time

Doramectin

OTC

45 days

Eprinomectin

OTC

None

Ivermectin**

OTC

48 days

Moxidectin

OTC

None

*The term non-lactating cattle is defined as including dairy bulls, dairy calves, and replacement heifers. Read the label indications carefully. Some products are not approved for non-ruminating calves and female dairy cattle 20 months of age and older. Some products cannot be used with veal calves. Carefully consult the labels.

** Not for use in female dairy cattle 20 months of age or older.

 

FDA-Approved Drugs for feed additive use in Non-lactating cattle*

 

Active ingredient

Drug type

Meat withholding time

Amprolium

OTC

24 hours

Bacitracin zinc

OTC

None

Bacitracin methylene disalicylate

OTC

None

Chlortetracycline

OTC

None to 7 days**

Chlortetracycline calcium

OTC

None

Chlortetracycline hydrochloride

OTC

None to 10 days**

Decoquinate

OTC

None

Fenbendazole

OTC

11 or 13 days

Lasalocid

OTC

None***

Morantel tartrate

OTC

14 days

Monensin (sodium)

OTC

None

Neomycin sulfate

OTC

1 day

Neomycin-oxytetracycline

OTC

0 to 30 days**

Oxytetracycline (quaternary salt)

OTC

0 to 5 days**

Oxytetracycline hydrochloride

OTC

0 to 5 days**

Oxytetracycline dihydrate

OTC

None

Poloxalene

OTC

None

Sulfamethazine

OTC

7 days

Virginiamycin

OTC

None

 

*The term non-lactating cattle is defined as including dairy bulls, dairy calves, and replacement heifers. Read the label indications carefully. Some products are not approved for non-ruminating calves and female dairy cattle 20 months of age and older. Some products cannot be used with veal calves. Carefully consult the labels.

** Withholding times depend upon manufacturer or labeled dosage used. Carefully consult the labels.

***Approved only for replacement heifers up to freshening or calving.

 

 

FDA-Approved Drugs for injectable use in Lactating cattle

Active ingredient

Drug type

Milk withholding time

Meat withholding time

Ampicillin trihydrate

Rx

48 hours

6 days

Ceftiofur crystalline-free acid

Rx

None

13 days

Ceftiofur hydrochloride

Rx

None

3 days

Ceftiofur sodium

Rx

None

4 days

Cloprostenol sodium

Rx

None

None

Dexamethasone

Rx

None

None

Dinoprost Tromethamine

Rx

None

None

Flunixin meglumine

Rx

36 hours

4 days

Gonadorelin diacetate tetrahydrate

Rx

None

None

Gonadorelin hydrochloride

Rx

None

None

Gonadotropin (chorionic)

Rx

None

None

Isoflupredone acetate

Rx

None

7 days

Oxytetracycline

OTC

96 hours

28 days

Oxytocin

Rx

None

None

Penicillin G (procaine)

OTC

48 hours

4 to 14 days*

Sometribove zinc

OTC

None

None

Sulfadimethoxine

OTC

60 hours

5 days

Tripelennamine hydrochloride

Rx

24 hours

4 days

*Withholding time depends on product manufacturer. Carefully consult the labels.

FDA-Approved Drugs for intramammary use in Lactating cattle

Active ingredient

Drug type

Milk withholding time

Meat withholding time

Amoxicillin trihydrate

Rx

60 hours

12 days

Ceftiofur hydrochloride

Rx

72 hours

2 days

Cephapirin (sodium)

OTC

96 hours

4 days

Cloxacillin (sodium)

Rx

48 hours

10 days

Hetacillin (potassium)

Rx

72 hours

10 days

Penicillin G (procaine)

OTC

60 hours

3 days

Pirlimycin

Rx

36 hours

9 days

 

FDA-Approved Drugs for oral use in Lactating cattle

Active ingredient

Drug type

Milk withholding time

Meat withholding time




Fenbendazole

OTC or Rx

None

8 days

Magnesium hydroxide

OTC

12 hours

None

Poloxalene

OTC

None

None

Sulfadimethoxine

OTC

60 hours

7 days




 

FDA-Approved Drugs for feed additive use in Lactating cattle

Active ingredient

Drug type

Milk withholding time

Meat withholding time

Fenbendazole

OTC

None

13 days

Monensin (sodium)

OTC

None

None

Morantel tartrate

OTC

None

14 days

Poloxalene

OTC

None

None

 

FDA-Approved Drugs for intrauterine use in Lactating cattle

Active ingredient

Drug type

Milk withholding time

Meat withholding time

Progesterone

OTC

None

None

 

FDA-Approved Drugs for topical use in Lactating cattle

Active ingredient

Drug type

Milk withholding time

Meat withholding time

Balsam peru oil

OTC

None

None

Castor oil

OTC

None

None

Eprinomectin

OTC

None

None

Moxidectin

OTC

None

None

Oxytetracycline hydrochloride/Polymyxin B sulfate

OTC

None

None

Trypsin

OTC

None

None


 Withdrawal Time video

Sensitivity of Testing video


Common causes of residues

Common causes of antibiotic residues in meat and milk

 

                Antibiotic residues do occassionaly occur in meat and milk from dairy cattle. Some common causes are listed here:

       Lack of consultation from a licensed veterinarian

       Not following veterinarian’s recommendation when using any drug

       Accidentally milking a treated cow into the bulk tank and not diverting from bulk tank

       Not following manufacturer- or veterinarian-prescribed label directions for correct treatment

       Not following manufacturer- or veterinarian-prescribed label directions for the appropriate withdrawal period

       Treatment not recorded as a written record – shipped or milked the cow too soon

       Poor identification of all cattle including bull calves

       Long-term residue following treatment as a calf (e.g. gentamicin)

       Use of medicated milk replacers in calves that may be sold for human consumption


Reasons residue is found #1 video


Reasons residue is found #2 and #3 video

Based on these common causes, producers can take the following steps to prevent residues:

  1. Have a valid veterinarian-client-patient relationship to ensure proper diagnosis and treatment of disease
  2. Develop a preventive animal health program to reduce the incidence of disease
  3. Use drug residue screening tests specific for the drug before marketing milk or meat
  4. Maintain milk quality and implement an effective mastitis management program to reduce the use of antibiotics
  5. Implement employee training and awareness of proper animal drug use
  6. Use drugs approved for specific disease indications according to label directions and withdrawal periods
  7. Keep records of all drug use and identify treated animals
  8. Do not use drugs that are prohibited for use in milking, dry, or growing animals
  9. Segregate and milk treated animals after, or in a separate facility from, all non-treated animals
  10. If in doubt about residue status, do not market milk or meat from treated animals

Residue Monitoring video

Other Sources of Residue video

The United States Department of Agriculture Food Safety and Inspection Service (FSIS) Office of Public Health Science, in the United States National Residue Program for Meat, Poultry, and Egg Products 2010 RESIDUE SAMPLE RESULTS, report that FSIS inspection personnel collected 211,733 samples in 2010. FSIS labs reported 2,043 residue violations in 1,609 animals (a single animal may have multiple violations): beef cows (84), bob veal (765), bulls (8), dairy cows (700), formula fed veal (3), goat (1), heavy calves (5), heifers (10), market hogs (8), non-formula fed veal (7), and steers (23). Neomycin accounted for the most residue violations (520 or 25%), followed by flunixin (285 or 14%) and penicillin (281 or 14%).  

Prevention Strategy video

The complete version of the video related to this subject (which contains additional information) can be viewed at: http://dairybeef.ucdavis.edu/residues_connection.html

 

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