Horse IM Injection: How to inject a horse IM (into the muscle or intramuscular) – 8-Step Guide with Video

Injecting a horse intramuscularly (IM) is a common procedure used to administer medications such as vaccines, antibiotics, and anti-inflammatory drugs. Here are the general steps for administering an IM injection to a horse:

Horse IM Injection

Step By Step Guide

Step 1. Gather supplies.

You will need the medication, a sterile needle (usually 1-1.5 inches in length), and a sterile syringe (usually 3-30 cc depending on the medication being administered).

Step 2. Choose the injection site.

The most common injection site is the neck, in the muscle group located just in front of the shoulder blade. Choose a spot that is free of any lumps, bumps, broken skin or other abnormalities. Make sure you are not too high in the nuchal ligament, or too low in the cervical vertebrae to inject. Make sure you are in the “Safe triangle” to inject in the neck.

Step 3. Prepare the syringe.

Draw up the medication into the syringe, being sure to expel any air bubbles. Make sure if you are drawing from a bottle you hold the bottle upside down to allow the medication to enter the syringe.

Step 4. Insert the needle.

Hold the syringe and needle like a dart, with the bevel (slanted end) of the needle pointing up. Insert the needle into the muscle at a 90-degree angle and with a quick, smooth motion. The most painful part is going through the skin so be quick. Often grabbing a pinch of skin in front of where you are going to inject will distract the horse enough to allow the needle to go in without flinching.

Step 5. Aspirate.

Before injecting the medication, gently pull back on the plunger to check for blood. If you see blood, withdraw the needle and try again in a different spot.

Step 6. Inject the medication.

If no blood is present, slowly inject the medication into the muscle.

Step 7. Withdraw the needle.

After the medication is injected, quickly and smoothly remove the needle.

Step 8. Dispose of supplies.

Discard the needle and syringe in a sharps container or other appropriate container.

Video: How To Inject A Horse IM

Visit our YouTube channel for more content: Exclusively Equine Veterinary Services


It’s important to note that if you’re not experienced with administering injections to horses, it’s best to have a veterinarian or experienced equine professional show you how to do it properly. Additionally, it’s important to always follow the medication instructions and dosage guidelines provided by your veterinarian.

Read More – Horse IV Injection: How to inject a Horse IV


  • Dr Louise Cosgrove

    The founder of Exclusively Equine Veterinary Services, Louise is driven to support horses in their recovery from injury or illness. A graduate of the University of Queensland, with international equin...

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