Best Wormer for Pinworms in Horses

Last Updated on December 28, 2021

It could happen to anyone – one day your horse has a beautiful, luscious tail and then BAM! He’s started rubbing the hair out on trees, fences, gates, stall doors – everything he can get his button. This particular type of itching is most likely caused by pinworms, but how can you pick the best wormer for pinworms in horses with so many on the market? Luckily, all the top options are available online, no matter which anthelmintic you choose!

They include Durvet 1.87% Ivermectin Paste, Schering/Intervet Panacur Paste, Merial Zimecterin Gold, Safeguard Horse Dewormer, and Durvet Pyrantel Paste.

What Are Pinworms in Horses?

The horse pinworm (Oxyuris equi) is an internal parasite that infects horses and is one of the most common causes of tail rubbing. Unfortunately, they can’t usually be identified in fecal floats, so your vet may need to take scrapings or tape the area around the anus to look for eggs. Occasionally, an adult pinworm can be found in the horse’s manure.

The adult female pinworm is roughly around 1-2 inches (3-5 cm.) in length, white, and has a pointed end just like a pin. When the time comes for her to lay her eggs she pokes out of the horse’s rectum and places them on the skin around the anus. 

The sticky glue used by the worm to hold the eggs in place causes itching, so the horse begins to rub their tail and hindquarters on everything.

This rubbing dislodges the eggs, which can fall into grass or hay, or they can get stuck to tail wraps, fence posts, and grooming supplies. These eggs survive a long time in the environment and can then be accidentally ingested by another horse, spreading the parasite, or the same horse. 

The eggs then hatch in the horse’s intestines and the pinworm life cycle starts over.

This rubbing is most often just annoying and only ruins your horse’s beautiful, long tail hairs. In some cases, the horse can rub hard enough to develop lesions on the tail, hindquarters, and perineal region, which now has the potential for a secondary infection.

Most horses don’t show any clinical signs of pinworms and they are considered to be one of the least dangerous parasites for horses. Whew!

What Else Can Cause Tail Rubbing?

It is important to rule out other causes of tail rubbing before stocking up on a bunch of dewormers. Using anthelmintics when they are not needed is linked to drug-resistant strains of worms!

Before anything else, you need to make sure your horse is clean! The buildup of dirt, sweat, fly spray, secretions, and skin flakes can make a horse incredibly uncomfortable

Mares with crud packed in their udder or geldings with gunk in their sheath can start to rub their tail in an effort to scratch those hard-to-reach places! 

If their private parts are nice and clean, you should take a closer look at their skin – especially around the tail head and the root of the mane. Dandruff can be super itchy and yes, horses can get it too! If you see lots of flakes, try to increase your grooming and use a good anti-dandruff shampoo.

Bugs are also an incredibly common culprit when it comes to equine itching. The sweet itch can be a frustrating menace because the true cause and cure can be tough to pin down. 

Culicoides midges are tiny, flying insects that like to bite horses on their bellies, manes, and tails and are one of the leading causes of seasonal itching. The bites of these midges cause an allergic reaction in horses, which in turn causes lots of itching.

Lice is another pest you might want to rule out as well. They are species-specific, which means you don’t have to worry about getting lice from your horse (or vise versa.) 

They are most commonly found on the head, shoulders, mane and tail dock, or even the back, neck, and leg pits, depending on the species. Part the hair and look for tiny eggs and even the adults if you have a really good eye!

How Do You Treat Pinworms in A Horse?

There has been concern over drug resistance recently, but a study with ivermectin and pyrantel pamoate shows that both are over 90% effective. Dewormer failure seems to be most often caused by improper dosing and not the resistance of the worms.

The anthelmintics that control pinworms are a common part of any good parasite control program and are easy find and dose. Most often a dose of ivermectin followed by a second dose three weeks later is enough, but it’s not your only option.

And no, it is NOT recommended to attempt to administer horse dewormers rectally, since pinworms are only there a very short time. That would be a great way to waste money and possibly upset your horse.

Veterinarians do recommend regularly washing the perineal area of horses with pinworms to clean off the eggs and glue and alleviate itching. Just remember to dispose of or disinfect all of your supplies!

Can Pinworms Be Prevented?

The recommended worming program for horses in the US usually involves a fecal test to look for eggs. Depending on the number of eggs found the horse will be classified as a low, medium, or high shedder

As mentioned earlier, pinworms usually won’t show up here, but all three groups will use a horse wormer that also controls pinworms. Staying diligent in your horse’s medical care prevents problems from arising and saves you money in the long run.

Another important part of parasite control is cleanliness. Manure should be regularly removed from paddocks and pastures and should be thoroughly composted before being used as fertilizer. 

Clean horses also have fewer skin problems and fewer parasites, so make sure to regularly groom everyone – even those pasture puffs!

Choosing the Best Wormer for Pinworms

1. Durvet 1.87% Ivermectin Paste

Durvet 1.87% Ivermectin Paste is probably something almost every equestrian has purchased at some point. It’s common, cheap, and effective! 

It has a decently high percentage of ivermectin so it can blast through those pesky worms. It can effectively control pinworms in horses and also treats large and small strongyles, ascarids, hairworms, bots, threadworms, and more! 

Ivermectin is notoriously safe and difficult to overdose, which can be comforting if you have a difficult to medicate a horse, like mine. Amazon also offers bulk options, so you can stock up on a bunch for all your horses, or for when you need to do multiple doses.

Ivermectin Paste Dewormer


  • Cheap
  • Effective
  • Safe


  • Some horses dislike the taste

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2. Schering/Intervet Panacur Paste

Panacur Paste uses 10% Fenbendazole and is effective at controlling large and small strongyles, ascarids, and pinworms. People often include this product in their rotation for deworming to avoid drug resistance.

INTERVET D PANACUR Dewormer Horse Paste


  • Effective
  • Great for rotating anthelmintics


  • More expensive
  • Some horses dislike the taste

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3. Merial Zimecterin Gold

Zimecterin Gold is a great general dewormer for horses. It controls large and small strongyles, tapeworms, roundworms, bots, ascarids, threadworms, and, of course, pinworms. 

The active ingredients are 1.55% Ivermectin and 7.75% praziquantel. The only complaints have been that the plunger can be a bit tricky to work, which can make the correct dosage more difficult.

Merial Zimecterin Gold Dewormer Paste for Horses


  • Effective


  • More expensive
  • Tricky Plunger
  • Some horses dislike the taste

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4. Safeguard Horse Dewormer

Safeguard is another fenbendazole dewormer that is effective to use on pinworms as well as large and small strongyles and ascarids. It is a little less expensive than the Panacur Paste and the taste is reported to be a bit better (to horses.)

Safeguard Horse Dewormer


  • Effective
  • Cheaper
  • More palatable


  • Doesn’t treat as many other worm species

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5. Durvet Pyrantel Paste

Pyrantel Paste is another good choice, however, you likely will need to double the dose for effective pinworm control which can make it more expensive than the other options. The active ingredient is pyrantel pamoate and only controls large and small strongyles, large roundworms, and pinworms. 

It contains more of this drug than other brands, which makes it a better choice if you are looking for pyrantel pamoate! Overall it is effective and easy to dose. 

Most horses don’t seem to mind the taste, which can be a relief for their owners.

Duramectin Ivermectin Paste for Horses


  • More palatable
  • Effective when dosed correctly
  • A cheaper option if you’re looking for pyrantel pamoate


  • Overall more expensive for just pinworm control
  • Requires double dosing

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As you can see, there are many excellent options out there for pinworm control! Ultimately, you need to make the decision if you need to treat only the pinworms, which drug you want to use, and how much you want to spend. 

While pinworms aren’t the most frightening parasite you’ll have to deal with as a horse owner, younger horses (and increasingly mature horses) can become very uncomfortable from high pinworm loads. 

So, if your horse starts the dreaded tail rubbing and is diagnosed with pinworms make sure to choose one of these excellent dewormers, give them a good scrub, and keep those pastures and paddocks clean!

Hopefully, this article helped you choose the best wormer for pinworms in horses and alleviated some of your concerns! If it helped you with your horse’s tail rubbing please share! 

Happy deworming!


What does pinworm look like in horses?

Adult pinworms are relatively easy to identify in horses: they are white and up to 15cm in length, and typically live in a horse's right dorsal colon. Pinworms in horses are most commonly associated with the development of perianal pruritus (itching of the tail), but can also cause colic, diarrhoea, weight loss and even death.

What is the life cycle of pinworms in horses?

It's highly efficient! Pinworms don't need to migrate through any organ tissue as common for other parasites. Their way of reproduction also works in their advantage since the eggs travel together with the herd of horses.
Pinworms live in horses's rectum. Adult female pinworms are laying yellow eggs around the horse's anus, leading to the worm being passed in droppings. The eggs are then picked up by another grazing animal, whereupon the pinworm larvae develop into adults. The larvae develop through various stages in the colon and become sexually mature in about five months. The adult worms then lay more eggs which are passed out in faeces, and so on. As horses migrate, they take the eggs and adults with them.

Is pinworm in horses contagious?

This infection may be passed to other horses if the horse has contact with the infected horse's manure. However, there is no evidence that this infection could be passed to humans or other animals through the same route. Of course, people can get pinworms from other people, but it's a different species that only affect humans.
In summary, people can't get horse pinworms, nor pinworms from any other animal species and other animals can't get horse pinworms.

How can you tell if a horse has parasites worms?

Some common symptoms of worms o parasites in horses are weight loss, colic, diarrhea, constipation, poor growth in foals, rough hair coat, and sometimes even respiratory problems. 
You can also test your horse for parasite or worm infection by having your vet do a fecal examination. This will reveal the presence of various parasites including pinworms, roundworms, whipworms, hookworms, ascarids, strongyles and others. Your vet may also check your horse for giardia, cryptosporidium, coccidia and/or salmonella. If your horse has any of these infections, you should treat him with the appropriate medications.

How long does it take to get rid of worms in horses?

The lifecycle of tapeworm takes six months to complete, so horses only need treating for it twice a year. Fenbendazole or moxidectin based wormers are the two types of wormer that can be used for this. 
Both are available over-the-counter and are safe for animals. It is important to remember though, that while these wormers do kill adult tapeworms, they do not kill the eggs that are passed out in the feces. This means that even if your horse has been treated with fenbendazole and it has been less than 6 months since the last treatment, it is still possible to get tapeworm again.  If you suspect that your horse has tapeworm, you should take a fecal sample and have it tested. This will allow the vet to confirm the diagnosis and advise on which wormer to use.