Deworming Programs and Schedules for Horses

Especially for first-time horse owners, the practice of deworming can be confusing and frustrating! How often do you need to deworm your horse? What us your horse worming schedule? What’s the difference between different types of dewormers? How do horses even get worms? 

It can all be overwhelming if it hasn’t been properly explained to you.  In this article, I hope to do exactly that. I’ll be discussing why horses need to be dewormed, what the different strands of equine-effecting worms are, which dewormers are used to prevent which kinds of worms, and what standardized deworming schedules for horses are.

Horse Worming Schedule: Why Deworm?

All horses need to be regularly dewormed to maintain their health.  It is one of the most critical aspects of horse care for horse owners to understand.  Most horse owners are well versed in deworming schedules, but for beginners, it can be daunting.

Horses spend lots of time outside, eat food off the ground, and in general, do lots of things. That could expose them to parasites and/or parasitic eggs of equine-effective worms.  Moreover, horses that develop worms have these parasites inside of their bodies.

Horse Worming Schedule: Why Deworm?

Horses that have worms can develop any number of health issues.  Some of these include gastrointestinal discomfort, loss of weight, loss of appetite, loss of muscle mass, diarrhea, and colic.  Horses with worms are typically characterized by a dull, clumpy coat that struggles to shed out.

Deworming prevents this.  Dewormers flush your horse of any parasites or parasitic eggs that may be present in or on their bodies.  Thankfully dewormers have an extremely high success weight; meaning that, as long as your horse is on a proper deworming schedule, he will not get worms.

Horse Worming Schedule: Types of Worms

There are four primary types of worms that affect equines: tapeworms, bots, ascarids, and strongyles.  Each different type of worm manifests itself differently within a horse’s body. Even so, the outward symptoms of an infected horse remain the same.

Tapeworms are carried by “forage mites” which are present both in hay and in the grass.  Horses pick up forage mites while eating, and in turn, are infected with tapeworms. Tapeworms make their home in a horse’s intestinal tract and will stay there unless flushed out by dewormers.


Bots come from flies laying their eggs on a horse’s coat.  If a horse cleans its coat or cleans another horse’s coat where these eggs are, bots then enter the horse’s system.  Bots also hatch and develop in the horse’s digestive organs, commonly the stomach.

Ascarids are commonly known as roundworms. They are commonly caught by horses under a year and a half old, as their immune systems aren’t quite at full strength.  Roundworms can cause serious detriments to a young horse’s health and growth if not treated properly.

Strongyles infect horses when they ingest larvae.  Strongyles also develop into parasites in the horse’s intestinal tract.  Different species of strongyles can cause horses to colic, lose weight, and have serious diarrhea.

Horse Worming Schedule: Types of Dewormers

There are many different kinds of dewormers, all with relatively complicated names.  Some of these names include Fenbendazole, Oxibendazole, Ivermectin, Moxidectin, Pyrantel Pamoate, Pyrantel Tartrate, and Praziquantel. 

Each one of these wormers attacks different strings of worms.  Sometimes they encompass more than one category of worms. For example, Strongyles are covered by each of the above-listed kinds of dewormers.


Ascarids (roundworms) are covered by Oxibendazole and Pyrantel Pamoate. Bots are covered by Ivermectin, Moxidectin, Pyrantel Tatrate, and Praziquantel. Tapeworms are covered by Praziquantel.

All of these types of dewormers are manufactured by different companies, which also go under different names.  Every tube of over-the-counter dewormer will detail what type of dewormer it contains, typically on the label sticker.

Dewormer can typically be purchased over-the-counter at your local feed shop or farm supply store.

Deworming Schedules

So, what do you do with all of this information? How do you create a schedule that gives your horse the protection that he needs? Thankfully, the experts have created schedules that do this for us.

The below link is to a study done by the Colorado State University that details deworming guidelines for different types of horses.  It shows that different types and quantities of dewormers are needed for different types of horses.

For example, it details different deworming schedules for pregnant mares, foals, and standard adult horses.  It details how frequently different dewormers should be used so that you can create your own schedule, depending on what type of horse you have, and when you’re beginning your schedule. Here’s the link to the Colorado State University Deworming Schedule.

Above all else when creating a deworming schedule, please consult your vet.  Your vet should be your first go-to resource on all equine medical topics. Discuss worming schedules with your vet before you give your horse any kind of over-the-counter dewormer.

Some vets include route deworming in their standard visits which, frequently, horse owners aren’t even aware of.  You don’t want to give your horse over-the-counter dewormer if your vet gave him the same dewormer on his visit two weeks ago.

Yes, do your research, and have a deworming game plan ready if necessary.  But ALWAYS consult with your vet about deworming before starting it on your own.


Deworming is a crucial aspect of horse ownership.  If you don’t know how to properly deworm your horse, you’re subjecting him to unnecessary discomfort and potential long-term health issues.

Deworming helps keep a horse healthy, happy, and comfortable.  Stay educated, and always consult with your vet when you have questions about deworming, or about other equine health topics.

I hope this article helped you better understand the deworming process and the formation of deworming schedules! If so, please share this article, and share with us your experiences deworming horses, and creating deworming schedules for horses!

Related Posts