Why you should routinely test your horse for worms and never just reach for the wormer!

So you want to be the best owner your pony could possibly have, right? 

And that means making sure your horse is as healthy and happy as possible.  

So why should you test your horse for worms?

Routine worming used to be part of the basic care of horses, at certain seasons you would just give your horse a specific wormer, but this is not the recommended advice anymore.

A major worm burden can be life-threatening to your horse.  
The damage worms leave in the gut can result in colic, diarrhoea and other significant problems that may impact the horse for his whole life even after treatment.

So making sure you treat your horse for worms is essential

But before you reach for the wormer STOP!

There are many different types of worms and parasites found in horses.

Wormers are developed to target and treat specific parasites. 

So you can’t just give any wormer, it needs to be the right one!  This is why you should test your horse for worms.

Also, over the last few decades, the old worming regime of giving wormers throughout the year enabled the parasites (worms) to become increasingly resistant to the ingredients in the wormers used to kill them off!  

Meaning that the more wormers we give the less effective they are becoming as the worms evolve to survive treatments!

Not to mention,  giving unnecessary drugs to your horse is never ideal for the animal and the chemicals in wormers are also damaging to the environment so we don’t want to be giving them unless we have to. (this saves you money too, but that is another blog post)

So which worms are found in horses?

The main culprits are:

  • Small Strongyles (Small Redworm)
  • Large Strongyles (Large Redworm)
  • Tapeworm
  • Round Worm
  • Pinworm
  • Encysted small redworm – The larval stage of small redworm. They bury into the lining of the gut and then emerge in the spring in full force resulting in diarrhoea and colic and 50% of cases result in death.

So how do you treat worms in horses?

As mentioned above parasites are becoming more and more resistant to wormers and their active ingredients.

So we always recommend you test your horse for worms before deciding on any treatment.


You simply buy a test kit online, collect a sample nugget, put in the enclosed bag (yes a glove is provided in the kit) and then post back to us in the prepaid envelope (even easier if there is a post box on the way home from your yard!).  

Once it arrives with us, we test your samples and produce a report based on the result.

The results will tell you what worms are present, and the burden of worms. (whether it is low, medium or high) all horses will have a burden, they are never 100% free, but we do not need to treat then unless they have a medium or high burden.

We will give you specific advice on whether your horse should be wormed or not and what sort of wormer you need to give (which targeted active ingredient).  

The standard kit will show the presence of adult worms, but not tapeworm, pinworm or encysted red worm.   You can buy a tapeworm saliva test here and a pinworm test here. Currently, there is no test for encysted small redworm although tests are being developed and we will update you if these become available.

Horse Pinworm Test kit
EFECS pinworm test kit

When should you worm count test?

You can test all year round.   

We recommend you worm count from March through until and including November, approximately every 8-10 weeks, depending upon the results, (this may need to be reduced to once every six weeks, or may be able to be increased to once every 12 weeks).

Over the Winter months December – January, the inhibited encysted small red worm will not show up on a faecal worm egg count, so it is possible you may get a misleading result,

What if you need to worm your horse?

Once you know what worms you need to treat, you can get a targeted wormer.

At Efecs we are an independent testing service with no affiliation to any worming companies so therefore you can be assured the advice given is not biased or influenced in any way.


Should your horse show a burden of worms we will let you know which wormers would treat the infestation best. You can then source a wormer for your horse.  

There are lots of online retailers you can buy from some local equine specialist shops.

Before giving the wormer, make sure you use a weight tape or weighbridge so you can give the correct dose.  

DO NOT just guess your horse’s weight!  

Again giving too much, or not enough wormer, means that you will not treat the infestation properly, and also risks helping the worms to build further resistance to the wormer making them much harder to treat!

Help your horse to keep worms at bay.

Keeping your fields and paddocks free of droppings regularly really helps.  

The lifecycle of worms is that they are passed in the droppings, they then move to the surrounding grass and are ingested again by yours and other horses.  So regular poo picking will really help, as well as rotation and resting of the field when you can.

Can you help us?

EFECS is on a mission to help, support and educate horse owners throughout the UK so please share this blog post if you found it useful, and you will help others can be responsible owners too.  (THANK YOU!)

Do you have any questions?

You can get in touch with us by email, on Facebook and Instagram.

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