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5 Things You Need to Know About Ivermectin for Horses

5 Things You Need to Know About Ivermectin for Horses

Horses are beautiful, intelligent creatures that require a great deal of care and attention. As their owners, it is our responsibility to keep them safe, healthy and free from any potential harm. Ivermectin is an effective and safe dewormer used to treat parasites and an essential product for maintaining your horse’s health and well-being. Horses are commonly exposed to parasitic worms because they are often in the outside elements. Parasites can live in their digestive tracts causing damage and harm. These worms can be kept to a tolerable level when you incorporate an effective deworming protocol.  This blog will provide you with the information you need to make an informed decision about deworming for your horse; including the benefits, efficacy and safety of Ivermectin, dosage and administration, and the potential side effects for horses so you can rest assured knowing they are healthy and happy!


5 Things You Need to Know About Ivermectin for Horses


1.   What is Ivermectin?

Ivermectin is a broad-spectrum medication specifically designed to effectively control parasites by blocking the nerve transmission and paralyzing them. It is a chemical dewormer that is packaged and sold in different forms like paste, get and liquid. Veterinarians have used this drug for years to treat animals that have parasitic worms. It has been approved by the FDA for treatment and used for equine deworming since being developed in the 1980s. Ivermectin is circulated under many generic and brand names, with the same formulation – 1.87% Ivermectin and 98.13% filler. It belongs to the Macrocyclic Lactones class of drugs that targets specific parasites at different stages of their development. In a single dose, Ivermectin kills and controls 43 species of parasites.


2.   What is Ivermectin Used For?

There are different parasitic conditions that Ivermectin can effectively treat. Two of the most common infections are strongyloidiasis and onchocerciasis. Strongyloidiasis is the intestinal parasite that horses can contract early in life. Foals as young as four days old can ingest the larvae in milk or obtain it through skin penetration. That often happens through bedding exposure. The parasite larvae work its way through the lungs and small intestines, creating the chance for a severe infection to take place quickly. Onchocerciasis is transmitted by fleas and causes dermatitis. It may not seem serious at first, but when left untreated, it can become acute. You may notice skin lesions and bleeding. Ivermectin can help control some of the most familiar parasitic worms. You’ve probably heard of these:

  • Roundworms
  • Pinworms
  • Hairworms
  • Stomach worms


3.   How To Administer Ivermectin

As mentioned, Ivermectin is potent, so a little goes a very long way with this medication. In horses weighing 1250 lbs, it takes only 6.08 grams to treat the 43 parasitic species mentioned. To illustrate it better, this means Ivermectin requires around a tenth of the amount other horse dewormers may need. Although it is powerful, ivermectin is safe when used correctly.

  1. The dose amount will always depend on the horse’s weight. The first step is to obtain your horse’s correct weight by using a livestock scale. Then, you can adjust the ivermectin dosage in the provided syringe.
  1. Most syringes will divide dosage spaces into five parts. These will be in 250 lb increments. Turn the ring on the syringe plunger ¼ turn to the left and slide it to the appropriate weight.
  1. Once ready, you’ll lock the syringe in place by turning the ring ¼ turn to the right. It is locked when it can no longer slide.
  1. Remove the syringe cover from the tip.
  1. Simply insert the syringe into the horse’s mouth between the teeth and depress the plunger all the way so that the paste is on the horse’s tongue.


4. How Long Until Ivermectin Starts to Work?

Ivermectin can begin working to kill parasites within 48 hours. Not all the parasites will be removed at that point. It is recommended that you test your horse’s worm burden before and after treatment to see how well it worked. This is called a fecal egg count, or FEC. The second FEC should be run ten to fourteen days after deworming. The goal is to reach a parasitic egg count of less than 95% from the first test. If this has not been accomplished within two weeks after treatment with Ivermectin, you should contact your veterinarian for possible resistance development.


5. Can You Give a Horse Too Much Ivermectin?

Since ivermectin was designed to kill a variety of internal and external parasites, it is highly potent in small amounts. Although Ivermectin toxicosis is rare, it can happen due to overdose accidents. For this reason, you must get the dosing accurately as calculated by your horse’s weight. When using Ivermectin to treat parasites in horses, it is important for horse owners to take note of its potential side effects. Skin irritation such as redness, itching, or swelling is commonly reported, while cases of mild gastrointestinal upset like vomiting are also possible. Although rare, neurological symptoms like seizures and behavioral changes may occur with Ivermectin treatment. If any of these reactions are observed in your horse, contact your veterinarian immediately. There are some symptoms to watch for that could mean you’ve given your horse too much ivermectin. These include:

  • Ataxia
  • Tremors
  • Salivation
  • Depression
  • Pupil dilation
  • Death

In addition to being aware of the risks associated with Ivermectin use, horse owners should also be sure to strictly follow their veterinarian’s dosages instructions when administering the drug. Overdosing can lead to serious health issues or even death due to poisoning; therefore, it is essential that you stick to the prescribed dosage and safety precautions provided by your vet. Ivermectin treatment is meant to be used with otherwise healthy horses. It is widely regarded as a safe means for deworming treatment, and again, cases of ivermectin toxicosis are extremely rare. It is regarded as a safe medication in most circumstances, but you always want to use caution and calculate the proper dose for your horse.


From Pasture to Performance: Ivermectin’s Role in Horse Health

Since no horse is completely immune to parasites, you need an effective way to treat them without causing damage to the animal. Horses graze and can consume some parasites while eating. These worms can tunnel through the horse’s respiratory, circulatory, and intestinal systems, until ending up in the horse’s large intestine residing there permanently if left untreated. They can cause ulcers, severe inflammation, and damage to the intestinal lining. With this guide and the guidance of your trusted veterinarian, you can implement an effective deworming method in conjunction with good parasite management practices to help slow the development of parasite infestation.