Your veterinarian has just left and instructed you to give your horse injectable medication. It is now up to you to give the needed medication properly and with as little pain as possible. If you have never given an injection to a horse before, here are some tips.
Most injectable medication given at home is intended to be given in the muscle (intramuscular). The best place to give these injections is in a large muscle, such as the haunches, thighs or neck.
This area is most likely to cause a problem and is not the best choice for an injection. The most likely problem is an infection or abscess. If an infection develops, it may be difficult to treat due to poor drainage. Usually, this area is reserved for injections of antibiotics. If you chose to give medication in the haunches, finding the best spot is easy. Draw a line (imaginary or with tape) from the top of the croup to the buttocks and a line from the dock of the tail to the point of the hip. The area where the two lines cross is the best place to insert the needle. Use caution when injecting since a startled horse has a tendency to kick.
This is considered the best place to give an injection but it may also be the place most likely to cause the horse to kick. An injection can be given anywhere along the back of the leg starting at 6 inches down from the top to the base of the thigh. Try to select the softest area.
Giving injections in the neck can be easy and effective as long as you know what to avoid. The spinal column and ligamentum nuchae (the tough ligament that supports the head and neck) should be avoided at all costs. If you are too close to the spinal column when you give an injection, you can cause nerve damage. Injections into the ligamentum nuchae can result in serious infections and ligament damage.
To give an injection in the neck safely, inject within the triangular space created by the ligamentum nuchae on top, the spinal column on the bottom and the shoulder blade on the side. This usually ends up in the middle of the neck, higher than you would think. The ligamentum nuchae runs just below the mane. The spinal column runs about midway down the neck.
Giving the Injection
Prior to injection, clean the area with alcohol or Betadine. This does not disinfect the area but it cleans off any large dirt particles. It is best to have someone help you hold your horse while you give the injection.
Draw up the medication into a syringe. Try to avoid air bubbles. Separate the needle from the syringe. It is best to place the needle into the muscle without the attached syringe. This way, if the horse jumps, you won't lose the needle and the medication – just the needle.
Decide where you are going to give the injection and insert the needle quickly and straight into the muscle. Do not use the technique of hitting the area multiple times prior to injecting. This is often done in livestock but only heightens the horse's sense that something is about to happen and can make an already nervous horse even worse.
After the needle is in place, look for any evidence of blood coming out of the needle. If no blood is seen, attach the medication-filled syringe. Pull back on the plunger and look in the syringe for any evidence of blood. If blood is seen, remove the needle and syringe and reposition. If no blood is seen, press on the plunger and inject the medication. If there is more than 15 milliliters of medication, use more than one site. After the medication has been given, pull the syringe and needle out of the muscle straight and quick.
Complications Infection or abscess at the site of the injection is the most common complication. This usually occurs with injections given in the haunches.
Injection into a blood vessel is unlikely but can occur. In some cases, giving the medication into a blood vessel can have devastating consequences. To make sure the needle is not in a blood vessel, draw back quickly on the plunger to see if blood enters the syringe. If there is blood, remove the needle and try another area.
Allergic reaction is possibly with any injection. Unfortunately, an allergic reaction does not occur on the first injection. It takes several exposures of the medication before the body is prepared to mount an allergic response. Watch for swelling, hives, weakness or difficulty breathing within one hour after injection.