March 6, 2019
Various medicines that livestock producers use to keep their herds healthy have guidelines to ensure that not only is the medicine administered in a safe and effective way, but also that the effects of the drug only impact the animal being treated and not the consumer down the road.
When producers treat their herd, it is important to be aware of and follow the different withdrawal times that list when an animal can be safely slaughtered or produce milk for human consumption.
In order to determine withdrawal times, researchers draw blood from the animal from the time that the drug is administered until it is virtually gone from their system or reduced to a safe concentration within the animal. This ensures that after slaughter there won't be any harmful residue of the drug in the carcass which could reach the consumer.
Dr. Ethan Andress of Hettinger, North Dakota, explained that drugs have varying withdrawal times because of the different ways that body tissues process, store, and clear out the different medicines. For example, some drugs are stored in fat cells while others are stored in the liver.
The withdrawal times listed on the medicine labels are calculated based off of the label's dosage instructions. This means that if the dosage of the drug is increased, the withdrawal time would change for that animal as well.
"Any usage where you are going off the label of the bottle should be done under direction of a veterinarian," Dr. Andress explained. Without a prescription from a vet, using the drug in any way that doesn't match label instructions is actually illegal.
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While veterinarians can prescribe off-label doses for injectable antibiotics and pour-ons, they are not allowed to go off the label when using feed grade antibiotics.
Justin Tupper of Saint Onge Livestock said that withdrawal times pertain mostly to cows and not calves because they are not yet at a finished weight and ready for slaughter. There is, however, a drug free market for bulls, and if producers would like to take advantage of that premium, they must sign a "drug-free certificate" regarding their bull.
While sale barns don't test for drugs in the cattle's systems, slaughter houses test carcasses for residue before processing the meat.
Being aware of the drugs that they are using, adhering to the withdrawal times, and selling their animals accordingly is primarily the producer's responsibility.
Below are some commonly prescribed drugs used by cattle producers. While some of these drugs are acceptable to use on other types of livestock, the information included pertains only to beef cattle. Prior to using any of these drugs it is important to read all label instructions to find out the proper dosage, administration, side effects, pre-cautions, and other information. Additionally, producers should consult their veterinarian to help create a treatment plan or to discuss additional uses for the drugs that may not be outlined on their labels.
Noromycin 300 LA – 3mL/100lbs body weight; 28 day withdrawal time; deep intermuscular or subcutaneous injection or intravenously; antibiotic that contains 300mg of oxytetracycline used to treat pneumonia, shipping fever complex, pink eye, foot rot, scours, wooden tongue, leptospirosis, wound infection, and/or acute metritis; dosage instructions may vary depending on the issue being treated
Liquamycin LA 200 – 4.5mL/100lbs body weight; 28 day withdrawal time; intermuscular, subcutaneous, or intravenous; contains broad spectrum antibiotic oxytetracycline; used to treat bacterial pneumonia, shipping fever complex, pink eye, foot rot, scours, wooden tongue, leptospirosis, wound infections and acute metritis
Penicillin Injectable (penicillin G) – 1mL/100lbs body weight; intramuscular injection; 14 day withdrawal time; used to treat bacterial pneumonia;
Draxxin – 1.1mL/100lbs body weight; 18 day withdrawal time; administered in a single subcutaneous dose in the neck; contains tulathromycin and is used to treat BRD infection bovine keratoconjunctivitis (IBK), and foot rot; do not use in dairy cattle 20 months or older
Resflor – 6mL/100lbs body weight; 38 day withdrawal time; subcutaneous injection in the neck only; solution of synthetic antibiotic florfenicol and flunixin used to treat bovine respiratory disease (BRD) and BRD associated pyrexia; not for use in dairy cattle 20 months or older.
Nuflor – Intramuscular application: 3mL/100lbs body weight; 28 day withdrawal time; Subcutaneous application: 6mL/100lbs; 38 day withdrawal; solution of the synthetic antibiotic florfenicol; used to treat BRD, foot rot, and other respiratory disease; not for use in dairy cattle 20 months or older
Excede – 1.5mL/100lbs body weight; 13 day withdrawal time; single subcutaneous injection on the back of the animal's ear near the base or where the ear attaches to the head (consult drug information for more details on how and where to administer); contains 200mg of ceftiofur/mL; used to treat BRD, shipping fever, pneumonia, foot rot, and acute metritis
Banamine – 1-2mL/100lbs body weight; 4 day withdrawal time; administer slowly intravenously; flunixin meglumine injection; typically used for pain in horses but used to treat pyrexia associated with BRD, endotoxemia, and acute bovine mastitis in cattle; can cause complicated or prolonged labor
LongRange – 1mL/110lbs body weight; 48 day withdrawal time; subcutaneous injection in front of the shoulder; extended release injectable parasiticide for treatment and control of internal and external parasites such as gastrointestinal round worms, lungworms, grubs, and mites; not for use in female dairy cattle 20 months or older, dry dairy cattle, breeding bulls, cattle managed in feed lots or under intensive rotational grazing
Dectomax (injectable) – 1mL/110lbs body weight; 35 day withdrawal time; subcutaneous injection into the neck; injectable broad spectrum parasiticide used to treat gastrointestinal round worms, lungworm, lice, and mites
Dectomax (pour-on) – 5mL/110lbs body weight; 45 day withdrawal time; apply topically along the mid-line of the back in a narrow strip between the withers and tail head; antiparasitic to treat gastrointestinal round worms, lungworms, eye worms, grubs, lice, horn flies, and mites; flammable
Ivomec (injection) – 1mL/110lbs body weight; 35 day withdrawal time; subcutaneous injection under the loose skin in front of or behind the shoulder; injectable parasiticide used to treat gastrointestinal round worms, lungworms, grubs, lice, and mites
Ivermectin (pour on) – 5mL/110lbs body weight when weight is between markings, use the next higher increment; 48 day withdrawal time; apply topically along the mid-line of the back in a narrow strip; parasiticide used to control gastrointestinal round worms, lungworms, cattle grubs, mites, lice, and horn flies; flammable
Clean-Up II – 3mL/100lbs body weight; 0 day withdrawal; pour along backline and down face; used to control live, flies, and cattle ticks; can be used on lactating and non-lactating cattle, calves, and mature horses.