Giving Injections to Animals
- When giving injections always get veterinary advice to make sure the injections are appropriate and you know the correct procedure. Follow the manufacturer’s instructions to the letter.
- Various pathogenic bacteria are present on the surface of the skin and these may produce infection if injected with the medication.
- Therefore; when time allows or for valuable animals, or if the environment is very dirty, every care should be taken to clean and disinfect the skin before injecting.
- If the injection is made on the side of the neck and the site is covered by hair or wool, close clipping of the skin is ideal, but careful separation of the coat and scrubbing the skin with a disinfectant may be possible.
- There are lots of preparations on the market which are satisfactory. Tincture of iodine is satisfactory and is better than methylated spirits which, though commonly used, is not effective as a disinfectant.
- A fresh swab of disinfectant should be used for each animal.
- Single syringes are mainly disposable these days but if a multiple-injection gun is re-used it must be disinfected frequently. The gun, including all parts coming in contact with the drug or the vaccine to be injected, should be placed in a large container such as a pressure cooker or saucepan and thoroughly boiled with the lid on. Bringing to the boil will kill all normal bacteria and boiling for 15 minutes will ensure the destruction of most bacterial spores.
- After boiling, the saucepan or container should be tipped sideways with the lid on so that the water drains out (like pouring off potatoes).
- With all the water out, the syringe and the plunger may be picked up by external parts only and carefully fitted together without touching any part which will contact the material injected. Wash and dry your hands before picking up and assembling the injection equipment.
- Equipment that cannot be boiled cannot be adequately disinfected. The best you can do is to soak it in a solution of disinfectant. Pour this off and then flush with cold boiled water. The latter should have been boiled in a lidded container and allowed to cool with the lid on.
- If they are not washed through thoroughly with water, the injecting guns and syringes may contain some of the disinfectant, and this may inactivate the vaccine, or cause irritation and damage of the tissues when injected.
- To remove vaccine or other medication from the bottle in a clean manner, swab the neck and stopper of the bottle with a solution of suitable disinfectant. If sealed with a rubber or plastic seal, the material may be withdrawn using a syringe and two needles (one needle to allow air in as the vaccine is sucked out).
- In practice, the above comments may be hopelessly impractical. For example, if you have to vaccinate 3000 lambs with enterotoxaemia vaccine, you will not want to disinfect the skin of each lamb. You may simply proceed down the race injecting each of the lambs in a clean part of the neck, taking care to keep your hands clean (and washing them if they become dirty), and taking care to keep the needle clean (and replacing it if it becomes dirty).
- Generally, use the smallest needle that is suitable, i.e. the needle with the narrowest bore, such as a 19-gauge needle. In tough-skinned cattle or in pigs a stouter needle may be necessary, e.g. a 16-gauge.
- This is the easiest and quickest form of injection, and it is used for many vaccines and drugs that are not irritant and are readily absorbed.
- With sheep in a race it is customary to give a subcutaneous injection by grasping up a handful of wool and skin to make a “tent” and sliding the needle into the base of the tent under the skin.
- With irritant materials, such as some vaccines, a lump may be produced. This may blemish the carcase of lambs when they are killed' and dressed. In such cases, the injection may be made at the top and to one side of the neck. In this position, any lump that occurs may be trimmed off when the carcase is dressed.
- With cattle, injection is usually made under the loose skin, either on the neck or just behind the shoulder.
- With horses, under the loose skin of the neck is convenient.
- With dogs and cats, the loose skin of the neck or behind the shoulder is convenient.
- With pigs, the skin below and behind the ear is convenient.
- Many drugs are better injected deeply into the muscles, because this gives more rapid absorption and may lead to less irritation.
- With all animals the intramuscular injection may be made deep into the muscles of the neck or in the main muscle mass of a hind quarter. (It’s important of course to try to avoid being kicked!)
- It is important that the injection is not into subcutaneous fat, and this can be a risk particularly with pigs.
- Just before injecting; withdraw the plunger of the syringe. If the needle has inadvertently gone into a blood vessel, blood will be withdrawn, in which case the needle must be moved to ensure the injection is intramuscular and not intravenous.
- If a resting spore of some clostridial organism, such as tetanus, blackleg, black disease or malignant oedema, is lying harmlessly in the muscle, the disturbance created by the injection may cause it to germinate leading to fatal disease. This is a good reason for keeping clostridial vaccinations up-to-date.
- Intravenous injections should only be carried out by a veterinarian or under veterinary supervision. It is up the veterinarian to decide if it is appropriate to delegate this task.
- Intravenous injections are generally given into the jugular vein.
- It requires considerable training and skill to give intravenous injections. If the vein is missed, there can be serious bleeding under the skin, and accidental injection of many medications around the vein instead of into it can cause a very nasty reaction, sometimes with sloughing of the skin.
- There are many medications that could kill or do serious damage if injected into a vein.
- Because the rapid injection of any medication into a vein can be lethal, all intravenous injections are given very slowly. For example, when injecting calcium solutions intravenously, a veterinarian may listen to the heartbeat to gauge the rate of injection by the response of the heart. Without this, sudden deaths may occur.
- The animal must also be fully restrained
- For large volumes, injections can be given from bottles or sachets with a long rubber tube attached to the needle so that the solution is gravity fed and the rate can be controlled by the height at which the bottle is held.