Giving Medication to Animals
Table of Contents
- Read the Label
- Extra-label Use of Drugs (elud)
- General Principles for Administering Injections
- Injection Techniques
- Consequences of Poor Injection Techniques
- Records of Treatment
For many medicines and vaccines, injection is the best method of
administration to an animal. Although the purpose of an injection
is to benefit the animal, if proper technique is not used an injection
has the potential to do harm. Poorly injected products may not be
well absorbed and may not work. The injection could create drug
residues, scar tissue, and/or abscesses that could cause the animal
pain and suffering.
Your veterinarian can instruct you on fine tuning your injection
techniques. This Factsheet provides a basic understanding of good
Read the Label
Before Using Any Product, Read the Label
Pharmaceutical manufacturers provide safe products that will effectively
treat a health problem, provided they are stored and used according
to label directions. Prior to licensing a product, research is conducted
to determine the best injection site, route and dosage for the treatment
of a particular condition in a particular species and class of animal.
This research is required for product licensure and provides the
information for the label instructions. Drug products approved by
Health Canada have Drug Identification Numbers (DINs) on the label
showing that their use is approved in Canada. Only use products
with DINs, unless your veterinarian advises differently.
An approved medicine will have a label displaying:
- the product name, the active ingredient and the concentration
of the drug
- product usage directions
- instructions for preparation if needed
- the formulation of the product, describing the contents of
- warning statements describing hazards to human health and safety
associated with handling the product and any restrictions on use
- the withdrawal time, the recommended time between the last
treatment and the slaughter of the animal for food (or sale of
- precautions statements that will alert you to storage and safe
handling requirements to maintain product stability and potency
- indications statements describing the species, class of livestock
and the disease conditions for which the product is to be used
- dosage and administration statements describing the directions
for use (e.g. how much, how often and for how long), the route
of administration (e.g. IM, SQ, IV) and the intervals between
- cautions and contraindications statements warning about hazards
to animal health and safety (e.g. potential adverse reactions)
- restricted uses, which are limitations for the use of the product
(for example "Do not use in lactating cattle")
- directions to read package insert for more detailed directions,
which alerts you to take special care when using the product,
or to the need to ask your veterinarian for more complete instructions
- the expiry date, which is the date past which the unopened
product should not be used
- the lot number, which is a record of the manufacturer's production
Extra-Label Use of Drugs (ELUD)
Products used in any manner other than that recommended on the
label are used in an extra-label (ELUD) manner. ELUD treatments
can ONLY be done on the specific, written recommendation of your
veterinarian, who will provide additional information needed to
use a product in the manner they are recommending.
Label withdrawal times may not be correct or the product may not
work as expected if label directions are not followed.
General Principles for Administering Injections
- Follow your veterinarian's directions for all injections.
- Pick an area of clean, dry skin for injection.
Preparing the Product
- Clean the bottle tops with a small amount of alcohol on a cotton
swab or ball.
- Only enter the bottle with a sterile needle. Never re-enter
a bottle of injectable medicine with a needle that has already
been used for an animal injection.
- Remove all needles from bottles prior to storage.
- Store all products according the label directions.
Using Clean Equipment
- Wash your hands before and after handling medicinal products.
- Use disposable syringes whenever possible.
- If using reusable syringes, use only hot water (no soap or
detergent) to rinse them before using modified live virus vaccines.
Chemicals may destroy the live virus and inactivate the vaccine.
- Use hot water and mild disinfectants to clean syringes for
other types of injectable products.
- After cleaning, sterilize reusable syringes before reusing
by autoclaving (high temperature, pressurized steam cleaning technique).
- Use a sterile needle for each animal.
- Use single use disposable needles whenever possible. Reusing
needles can transmit infections (such as Bovine Leukemia Virus)
from animal to animal.
- Occasionally the same needle may be used for multiple injections
(i.e., when giving many doses in a short period of time, such
as with injectable worming products in feedlot cattle). If doing
so change the needle frequently ( i.e. every 10 animals).
- Choose the smallest needle size (diameter) that is reasonable
to use for the product type and volume to be injected. This will
minimize tissue damage and reduce leakage of the product from
the injection site.
- Choose needles of the correct length for the type of injection
you are giving and suitable for the size of animal being injected.
Shorter needles (1.0 or 0.5 in.) can be used for subcutaneous
injections; longer ones (1.5 in.) for intra-muscular injections.
Smaller animals (i.e. calves) have smaller muscle masses and should
be injected with needles of appropriate length to prevent injury
to nerves and other tissues.
- Good animal restraint prevents injury to you and the animal.
Good restraint prevents needles from breaking off at the hub when
the animal moves suddenly, prevents accidental self-injection
and allows good visualization of injection sites.
Volume of Product to Inject
- Inject quantities no greater than that recommended on the label,
at one body site.
- Split large volumes into smaller amounts and inject at different
locations. Generally for IM injections, inject no more than 10
mL per site. For SQ injections, inject no more than 20 mL per
- Do not combine vaccines or products in the same bottle or syringe
unless the label clearly states to do so. Mixing can adversely
affect the products by changing the pH, the chemical composition,
or by causing components of the drug to precipitate out of solution.
- Shake or agitate products as directed on the label prior to
use to ensure that they stay in proper suspension in the bottle.
- Choose muscle tissue of lesser value to consumers for IM injections.
In cattle, for example, IM injections where possible, are often
given in the neck area instead of the hip.
- Draw air into the syringe and inject the same volume of air
into the bottle as the volume you plan to take out of the bottle
to equalize the pressure. Failure to do so will make it difficult
to withdraw the contents of the vial or bottle.
- After filling the syringe with the product to be injected,
point the syringe upwards and tap the barrel with your finger
to make air bubbles move upwards into the syringe tip. Slowly
and carefully push the plunger to eject the air bubbles from the
syringe before injecting the product.
- Give IM injections deep into a muscle. Use a needle long enough
to penetrate skin, subcutaneous tissue and fat to reach the muscle.
The needle should enter the skin perpendicular to the skin surface.
- Insert the needle into the animal, and then attach the syringe
to the needle. Check that the needle is not in a blood vessel
by pulling back on the plunger and observing for blood flow in
the tip of the syringe. If blood appears, remove the needle and
put it in a different location at least one inch away from the
original injection site.
- Generally, you can choose the subcutaneous (SQ) route when
given a choice of either the intramuscular (IM) or SQ on the product
- Give SQ injections half way up the neck in front of the shoulder,
or over the ribs well behind the shoulder.
- Use a 0.5 to 1 inch long needle.
- To give SQ injections for cattle, lift a fold of skin to make
a skin "tent". Insert the needle through one side of
the tent at an angle of 30 to 45 degrees relative to the surface
of the body. For swine, it won't be possible to make a "tent",
so slide the needle under the skin at an angle of about 30 degrees
from parallel to the skin surface and inject.
- For IV injections, get advice and training from your veterinarian,
as this is a specialized technique that requires expertise and
- Choose different injection sites on the body (e.g. opposite
sides of the neck) when repeating treatments over a number of
- Place repeat injections at least 4 inches, or one hand-width
from a previous injection site.
Consequences of Poor Injection Techniques
- Treatment failure, if product absorption is delayed or blocked.
- Drug residues in meat or milk if the drug can not be absorbed
and metabolized in a timely manner.
- Animal suffering and incapacitation due to nerve damage and
swelling from tissue reactions.
- Excessive trim at slaughter due to abscess, scarring, broken
- Shock or death of the animal being treated, if medications
unintentionally enter the bloodstream.
- Accidental human injection.
Records of Treatment
All treatments given to food animals should be permanently recorded
to ensure withdrawal time requirements are met and to improve treatment
decisions and success.
- Keep permanent written records of treatments administered to
individuals or groups of animals.
- Record the animal's identification, date(s) the treatment was
given, product name, amount given, the route, site and time when
meat or milk will be ready for sale.
- Have your veterinarian leave legible, written instructions
for use when medications are being dispensed, especially if they
are recommending the use of a product in a manner different than
the label directions.
- Save the box tops or labels of products used. This provides
a list of product names, lot numbers and expiry dates. Record
the date of use on the box top or label to provide a permanent
record of when a particular product was used.
- Keep a current package insert for products commonly used in
a file or drawer for reference.
For more information:
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