#horseworms

Worm infestations in horses are more common than many owners realize. Even horses that appear healthy can carry internal parasites that slowly affect their well-being. If not managed properly, these parasites can lead to serious health issues. Understanding the different types of worms, spotting early signs, and following the best deworming routine are key parts of responsible horse care.

This guide covers everything horse owners need to know to stay ahead of worm problems—from redworms to the best deworming practices available.

Why Worm Control Is So Important

Internal parasites can harm a horse from the inside out. They steal nutrients, damage organs, and affect how a horse digests food. Some types can even lead to colic or weight loss that doesn't improve with better feeding.

Worms can be silent threats. Often, symptoms appear only after the infestation has caused enough damage. That’s why regular parasite control isn’t optional—it’s a core part of good horse management.

Types of Worms Common in Horses

Here are the main worms that affect horses, along with what they do and how they impact health.

Small Strongyles (Redworms)

Also called redworms, small strongyles are one of the most dangerous and widespread parasites in adult horses. They can encyst in the gut wall and lie dormant for months before emerging all at once, causing inflammation and digestive upset. Moxidectin and a 5-day fenbendazole treatment are most effective against encysted larvae.

Large Strongyles (Bloodworms)

These parasites can migrate through blood vessels and cause severe internal damage. Though less common today thanks to modern dewormers, they’re still a risk if left unchecked.

Roundworms (Ascarids)

Roundworms are more common in foals and younger horses. They can cause respiratory issues, poor growth, and even intestinal blockages. Regular deworming early in life is crucial to prevent heavy infestations.

Tapeworms

Tapeworms attach at the junction of the small and large intestine and often go unnoticed. However, they can cause colic, poor digestion, and weight issues. Praziquantel-based dewormers are typically used in fall or spring to target these parasites.

Bots

Bot fly larvae can be found in the horse's stomach after being ingested from eggs laid on the skin. They don’t always show symptoms, but a heavy load can cause stomach irritation. Ivermectin and moxidectin both work against bots.

How to Spot Worms in Horses

Not all horses show obvious signs of worms. Still, these symptoms are commonly associated with parasite infestations:

Sudden or unexplained weight loss

Rough or dull coat

Diarrhea or frequent mild colic

Pot-bellied look, especially in young horses

Scratching the tail or rubbing hindquarters

Lethargy or reduced performance

Poor appetite or inconsistent eating habits

Coughing in foals or young horses (due to migrating roundworms)

If your horse is showing one or more of these signs, it’s time to take a closer look—and likely, a fecal test.

Deworming Practices That Work

Deworming isn’t just about giving a paste every few months. Today’s approach is smarter and more targeted.

Start with a Fecal Egg Count (FEC)

This simple test checks how many worm eggs are in your horse’s manure. It helps you avoid unnecessary deworming and choose the right product. Many vets recommend doing FEC testing two to four times per year, depending on your horse’s risk level.

Deworm Based on Age and Risk

Foals and yearlings need more frequent deworming due to their higher susceptibility Adult horses benefit from strategic deworming based on FEC results High-risk horses (those in crowded fields or with past worm problems) may need a stricter schedule

Stop Rotating Blindly

Rotational deworming used to be the norm, but it's no longer recommended without FEC data. Overuse of dewormers contributes to resistance, making treatments less effective over time.

What Dewormers Treat Which Worms

Here's a breakdown of commonly used dewormers and what they target:

Dewormer Effective Against

Ivermectin Bots, strongyles, roundworms

Moxidectin Encysted small strongyles, bots

Fenbendazole (5-day) Encysted redworms, roundworms

Pyrantel (double dose) Adult strongyles, tapeworms

Praziquantel Tapeworms (used in combo formulas)

Top Picks Available Through Pet Supplies Online:

These trusted dewormers are often available from stores offering reliable pet care products and horse supplies online:

Eqvalan Oral Paste Horses (Ivermectin) – Great for bots and strongyles

Panacur Equine Guard Horse Wormer (Fenbendazole) – Ideal for encysted small redworms

Equest Gel Horse Wormer (Moxidectin) – Long-lasting control, especially effective for larval stages

Strongid P Paste (Pyrantel Pamoate) – Used in double doses for tapeworms

Equimax (Ivermectin + Praziquantel) – Broad-spectrum treatment, includes tapeworm control

Always dose based on your horse’s weight and follow label instructions carefully.

Prevent Worms Before They Start

Deworming is important, but prevention is just as critical. Here's how to reduce worm exposure:

Remove manure regularly from paddocks and stalls

Rotate pastures if possible

Don’t overstock pastures with too many horses

Use separate feeding and watering areas to prevent contamination

Keep feed clean and stored properly

Regularly groom your horse to remove bot eggs from legs and coat

Stick to a parasite control schedule advised by your vet

What About Dewormer Resistance?

Worms can become resistant to certain medications when horses are over-treated or treated incorrectly. That’s why using FEC results and choosing the right dewormer at the right time is so important. Only deworm when needed, and use the correct dose based on your horse’s weight.

Final Thoughts

Worm control isn’t just about reacting to problems—it’s about preventing them. By understanding the types of worms, recognizing signs early, and following a smart deworming plan, you can keep your horse in top shape.

Look for reliable pet supplies online that offer a wide range of parasite treatments and dewormers. Choose products that are effective, easy to administer, and suited to your horse’s specific needs.