The 8 Best Horse Wormers: Different Parasites & Treatment

When it comes to managing internal parasites in horses, it takes more than just giving a generic wormer a few times a year. Especially since horse parasites are becoming more and more resistant to treatments. This is why it's important to use the best horse wormers alongside a worming program for complete parasite control.

Discover below, all the information you need to provide the best protection for your horse against parasites.

Horse Wormers at a Glance

The best horse wormers aren't interchangeable. Match the active ingredient to the parasites your vet wants to target, then check that it still works on your yard. This comparison shows the main differences between the eight products below.

How Do Horses Get Worms?

The most common way that horses become infested with worms is by grazing on contaminated pasture or from being around other infected horses.

Most worms are ingested as tiny larvae and then develop into worms in your horse's digestive tract. Many intestinal worms pass eggs in the horse's manure. These can develop into infective stages in the environment and be picked up again when horses graze.

When you use a wormer for horses, you're targeting particular parasites inside the horse. Pasture management is still needed to reduce contamination and reinfection

How Can You Tell If Your Horse Has Worms?

One way to tell if your horse has a worm infestation is if you notice a deterioration in its condition. It may become lethargic and lose its appetite which will lead to weight loss, loss of condition and a dull coat.

If the horse is heavily infected the worms can cause diarrhea and regular bouts of colic. Other signs to look out for include wounds on the skin that aren't healing and coughing.

These signs can have other causes, and a horse can carry parasites without looking unwell. Colic, persistent diarrhea or unexplained weight loss needs veterinary attention; a fecal egg count alone doesn't diagnose the cause.

What Are The Most Common Types of Worms?

Below we'll take a look at the most common type of horse worms and their seasonal habits and life cycles. In order to provide the best worm treatment for your horse, it's important to identify exactly what one you're treating it for.

Bots

Bots first appear as small yellow eggs, laid by flies on the horse's forelegs, neck and chest. Grooming can stimulate the eggs to hatch, allowing larvae to enter the mouth. The larvae develop in the tissues of the mouth before moving to the stomach, where they attach to the lining. Bots can irritate the mouth and stomach, although most infestations cause little obvious illness. After eight months in the stomach, the larvae are passed in manure, then pupate in the soil before emerging as flies, and the cycle starts again.

Ivermectin is generally more consistently effective against bots than moxidectin. Your vet can advise when treatment is appropriate locally; there's no need to wait for the first frost as a universal rule.

Tapeworms

Horses have their own tapeworm species; these aren't the same tapeworms commonly found in cats and dogs. Tapeworm eggs are first eaten by foraging mites that live in the grass. Horses then eat these mites when they’re grazing. After a horse eats an infected mite, the tapeworm develops in the intestine, commonly near the junction of the small intestine and cecum. Tapeworms can cause inflammation and are associated with certain types of colic and intestinal obstruction. Tapeworm eggs are passed out in faeces and the cycle starts again.

Praziquantel-containing wormers are an option for tapeworm treatment. Pyrantel is also used in an appropriate tapeworm regimen, but its routine dose isn't interchangeable with that regimen. Let your vet decide the timing and need for treatment rather than following a fixed March-and-September rule.

Pinworms

Pinworms mature and develop in the large intestine and rectum of horses which causes them to be very itchy around the tail. The horse will then smear the eggs onto any surface it's rubbing on. These eggs can be picked up by another horse and they can also be passed on through contaminated food or bedding.

They have a five-month life cycle. Fenbendazole or oxibendazole can be useful against pinworms, while response to other drugs can vary. Clean contaminated stable surfaces and follow your vet's advice; treating the horse without tackling the eggs around the yard can leave the problem going round in circles.

Threadworms

These threadworms are common in foals and have a two-week life cycle so it's a quick turn around. Foals can be infected from their mother's milk if she is infected and also by contaminated pasture or bedding. Young horses develop immunity as they mature. Threadworms are only rarely the cause of diarrhea in foals, so don't assume worming will solve it. A foal with diarrhea can dehydrate quickly and needs veterinary attention. Ask your vet whether treatment of the mare is warranted.

Ivermectin or oxibendazole may be used under veterinary direction. Moxidectin isn't an appropriate choice for a young foal: Quest and Quest Plus are labeled for horses and ponies at least six months old.

Ascarids

These are also known as roundworms and are ingested as eggs. The eggs hatch in the intestine. Larvae migrate through the liver and lungs before returning to the small intestine, where they mature into adult worms. As you can imagine, if this worm isn't treated it can do a lot of damage to your horse's health.

Ascarid resistance to ivermectin and moxidectin is widespread. Fenbendazole or pyrantel may be suitable, but your vet should choose a treatment that works against the local parasite population. Ascarids can particularly be a problem in young horses and they will need regular treatments against them. These worms have a three-month life cycle but eggs can live dormant for years in the earth.

Large and Small Strongyles

These worms can be highly damaging to your horse and are also known as bloodworms or redworms. The two common types are small strongyles and large strongyles. They start out as larvae that live on grass which is eaten by your horse. Large strongyles such as Strongylus vulgaris can damage the arteries supplying the intestine and cause serious colic. Small-strongyle larvae burrow into the intestinal wall; mass emergence of these encysted larvae can cause severe diarrhea and colitis.

The right treatment depends on the worm's life stage and the drugs that still work on your property. Moxidectin and an appropriate five-day fenbendazole course have larvicidal claims, but a routine single dose of fenbendazole doesn't provide that same coverage. Resistance can limit treatment success. Seasonal planning should reflect the local climate; hot weather doesn't simply kill worms already inside the horse.

What Is the Best Way to Manage and Prevent Worms?

Lots of veterinarians are now recommending that instead of giving a horse wormer every few months, it's better to tackle parasite control in a more holistic way. This not only minimizes the amount of chemicals your horse is ingesting but it also helps slow the development of drug resistance.

For the very best worm prevention and treatment then its necessary to observe the following things.

Pasture Management

Pasture management and rotation is vitally important as this is where your horse will predominantly pick worms up. Make sure that the pasture isn’t overcrowded with too many horses per acre and rotate the pasture if possible. Resting pasture can help, but how long infective stages survive depends on the parasite, weather and season. A fixed six-month break doesn't guarantee clean grazing.

When feeding roughage in the pasture, feed it from a rack to prevent the horse's mouth from touching the ground and possibly picking up worms. Where a rack isn't practical, a suitable hay bag can help keep forage off dirty ground.

To safe guard young horses it's a good idea to group horses of a similar age together. Keeping mares and foals away from adult horses, and yearlings away from old horses for example.

Lastly, it's vital to remove droppings every day, or as regularly as possible from the horses stable or pasture.

Fecal Egg Count

These days it’s very easy for your veterinarian to do a fecal egg count from a sample of your horse's feces.

Fecal egg counts help identify low, moderate and high strongyle egg shedders; they can also be useful for detecting ascarid eggs in young horses. They don't measure the horse's total worm burden or tell you which product will work.

A fecal egg count reduction test compares samples taken before and after treatment to check whether the drug is effective. Your vet can arrange this as part of the worming program.

Routine fecal egg counts don't reliably detect tapeworms, bots, pinworms or encysted small-strongyle larvae. Additional tests may be useful in some situations, but there isn't one blood or saliva test that identifies every missed parasite.

Horse Worming Schedule

Plan your deworming program with your vet and review it at least annually. For optimum results, discuss it with professionals and see what your vet says.

For adult horses, the AAEP recommends a baseline of one or two treatments a year, with additional treatment for higher egg shedders and specific parasite risks. This isn't a foal schedule. Your horse's age, test results, local conditions and treatment efficacy should guide the plan, rather than automatically worming every few months or choosing a brand by the calendar.

How Often Should I Use a Horse Dewormer?

Horses will develop their own individual immunity against worms and some will be more resistant to others. This is why they should be treated for their individual needs when it comes to their deworming schedule. Here are some general guidelines you can follow.

Age

Foals and young horses need an age-specific worming program agreed with the vet; an adult schedule doesn't cover their different parasite risks. This is because they haven’t yet built up a natural resistance which makes them particularly susceptible to worms (see a horses growth stages). Parasite infections can stunt the growth of a young horse cause a potbelly.

Weight

If your horse doesn’t get the right dosage then the treatment will be ineffective. Not having enough wormer will also harden the resistance of the worms. That’s why it's important to give the right amount.

A weighbridge gives the most accurate body weight. A weight tape can help you estimate your horse's weight, but it isn't an exact measurement. Follow the product label and your vet's dosing advice.

The Severity of Infection

A suspected heavy infection needs a veterinary plan, not a stronger dose chosen at home. Killing a heavy ascarid burden can cause intestinal blockage, especially in young horses. Moxidectin isn't resistance-proof, and Quest products must not be used in sick, debilitated or underweight horses. Egg counts help guide control of shedding; they don't measure how severely ill a horse is.

Special Conditions

Before introducing a new horse, ask your vet about quarantine, testing and treatment. Keeping it off shared pasture and checking treatment efficacy helps reduce the risk of bringing resistant parasites onto the property. Travel and seasonal risks should be assessed individually; neither showing nor a particular month automatically means the horse needs another wormer.

Reviews Of The 8 Most Popular Wormers

Here's how the eight wormers compare in practice. Some share the same active ingredient, so changing the name on the tube doesn't necessarily change the treatment. The useful choice is the one that fits your horse's veterinary plan.

1. Equimax Paste

This horse wormer from Equimax covers most of the major internal parasites found in horses. The active ingredients ivermectin and praziquantel provide bot and tapeworm coverage in one treatment. Equimax is labeled for foals from four weeks old and for pregnant or lactating mares and breeding stallions. It doesn't treat encysted small-strongyle larvae, so it won't cover every job on the worming calendar.

Pros

• Combines ivermectin and tapeworm treatment in one paste.
• Label includes breeding horses and foals from four weeks old.

Cons

• No encysted small-strongyle coverage.
• Broad label coverage doesn't overcome resistance to ivermectin.

2. Zimecterin Gold

This horse deworming paste contains ivermectin and praziquantel, combining bot and tapeworm coverage in one treatment. One dose will cover a horse weighing up to 1,250lb and will cover the parasites listed on its label, subject to local resistance.

The label allows use from two months of age, but the product hasn't been tested in pregnant or lactating mares or breeding horses. Rare mouth irritation has also been reported. Those are useful differences to check before treating Gold as a straight swap for Equimax.

Pros

• Includes tapeworm treatment alongside ivermectin.
• One tube is labeled to treat up to 1,250 lb at the recommended dose.

Cons

• No encysted small-strongyle coverage.
• Breeding-horse testing and mouth-irritation cautions need consideration.

3. Durvet Ivermectin Paste

This ivermectin paste from Durvet will be particularly appealing to your horse with its apple flavour.

This 1.87% ivermectin paste is labeled for bots and several other equine parasites. It doesn't contain praziquantel, so don't expect tapeworm coverage, and it won't treat encysted small-strongyle larvae. Ascarid resistance is another reason to check the plan with your vet, particularly for young horses.

Pros

• Apple-flavored syringe paste.
• Bot coverage without adding a tapeworm drug when that isn't needed.

Cons

• No tapeworm or encysted small-strongyle coverage.
• Ivermectin isn't a reliable default for resistant ascarids.

4. Quest Plus Gel

Quest Plus combines moxidectin with praziquantel, giving it label coverage for encysted small-strongyle larvae and tapeworms. That makes it a useful option when those are the targets in your horse's plan. It isn't a cure-all, though: the horse must be at least six months old, and the label says not to use it in sick, debilitated or underweight animals. Accurate weight-based dosing matters.

Pros

• Encysted small-strongyle and tapeworm coverage in one treatment.
• Single-treatment gel rather than a five-day fenbendazole course.

Cons

• Unsuitable for foals under six months and sick or underweight horses.
• Moxidectin resistance can occur; efficacy still needs monitoring

5. Safe-Guard Horse Dewormer Paste

This wormer from Safeguard is a fenbendazole based wormer and can be used to treat strongyles, pinworms and a range of equine parasites. Your horse will find the cinnamon apple flavor very appealing; any combination treatment should be agreed with your vet.

Fenbendazole treatment depends on the parasite and regimen. A routine dose isn't the same as the five-day larvicidal course, and small-strongyle resistance is common. Safe-Guard also doesn't cover bots or tapeworms, so check what your horse actually needs before reaching for the familiar tube.

Pros

• Apple-cinnamon paste for susceptible labeled parasites.
• Provides a fenbendazole option within a vet-directed plan.

Cons

• No bot or tapeworm coverage.
• A standard dose doesn't provide the five-day larvicidal regimen's claims.

6. Safe-Guard Equi-bits Deworming Pellets

If you have a horse who really can't bear a syringe in its mouth, then this product is a great alternative to worming paste. The tasty, alfalfa-based pellets contain fenbendazole, good for strongyles and can be added to your horse's food.

Equi-bits is a one-day fenbendazole feed treatment, not a daily preventative wormer. The horse has to eat the full medicated ration for it to receive the intended dose. That makes it handy for a horse that hates a syringe, but less straightforward for a fussy feeder or horses sharing feed.

Pros

• Useful alternative when administering a paste is difficult.
• Alfalfa-based pellets mix into the horse's normal ration.

Cons

• Leaving medicated feed behind can mean an incomplete dose.
• No bot or tapeworm coverage; fenbendazole resistance remains relevant.

7. Panacur Horse Dewormer Paste

This apple flavor wormer is made in the USA and is one of the most common horse dewormers.

The active ingredient is fenbendazole, with label claims for susceptible strongyles, pinworms and ascarids. Encysted small-strongyle claims require the appropriate five-day regimen; an ordinary single dose doesn't provide that treatment. Panacur and Safe-Guard share the same active ingredient, so swapping between them isn't a change of drug class. This listing is a pack of ordinary paste tubes, not a Panacur PowerPac kit.

Pros

• Familiar syringe paste with a clearly identified active ingredient.
• A fenbendazole option where efficacy has been established.

Cons

• No bot or tapeworm coverage.
• Ordinary paste and the five-day larvicidal regimen mustn't be confused.

8. Strongid Paste

Strongid Paste contains pyrantel pamoate and is labeled for certain mature strongyles, pinworms and roundworms. It's an option when your vet wants to use pyrantel and knows it remains effective locally. The standard paste label doesn't include bots, tapeworms or encysted small-strongyle larvae, so don't choose it expecting the same coverage as Quest Plus or an ivermectin/praziquantel combination.

Pros

• Adds a pyrantel option to the comparison.
• Syringe paste for the susceptible adult worms listed on its label.

Cons

• No bot or encysted small-strongyle coverage.
• Routine labeled use doesn't provide tapeworm coverage.

Conclusion

As you can see, managing animal parasites in your horse isn't as simple as using a wormer twice a year. In order to fight parasites effectively and reduce parasite contamination on pasture, it's important to be conscientious about your deworming schedule as well as the products you use.

Pasture management and fecal counts may be used in conjunction with the best wormers for horses to control parasites in your horse and reduce contamination of its grazing environment. If you keep on top of the parasites, your horse will definitely thank you for it!