Targeted worming for horses

Worming is an essential consideration when caring for horses. 

Although a horse can naturally carry a small amount of worms without it causing them any health issues or unpleasant symptoms, it’s vital to keep parasite numbers low.   

There are many different types of worms, classed as “Helminths” or parasitic worms, that can cause horses to suffer symptoms such as colic, weight loss, and diarrhoea. Sometimes, the impact of carrying a high number of worms can be life-threatening for horses.

Important: When discussing worms and parasites, we are not referring to earthworms – which are an essential species that can break down horse droppings and help to maintain a healthy pasture.

Here are a few of the worms we need to protect our horses from:

• Tapeworm.
• Small redworm.
• Large redworm.
• Roundworm.
• Lungworm.

The above parasites are active at different times of the year, depending on their life cycles. So, it’s important for us to be vigilant with our worming and pasture management practices throughout the seasons, to reduce the risk of worms and keep our horses healthy. 

Read on, to learn more about why it’s important to worm your horse, discover what targeted worming is, and view an example of a targeted worming programme…

• Why it is important to worm your horse?
• What is targeted worming?
• Types of testing available for targeted worming.
• Step by step guide to collecting a sample for FWEC (Faecal Worm Egg Counts).
• Step by step guide to performing a tapeworm saliva test.
• Example of a targeted worming programme.
• Benefits of a targeted worming programme.

Why is it important to worm your horse?

We worm our horses by giving them something called a ‘wormer’. A wormer is a product intended to protect them from the negative impacts of a worm burden (having too many worms in their body), which causes serious health problems.

Wormers contain active ingredients that destroy specific types of worms, and traditionally, owners would give their horses wormer on a regular basis to protect from these harmful parasites. 

However, thanks to advancements in scientific research, we’re now aware that worms can develop resistance to the active ingredients in worming products. Unfortunately, when parasites become resistant to the active ingredients used in worming products, those products are no longer effective at protecting our horses from worms. 

Therefore, we have to develop new worming practices to address the issue of wormer resistance – which is why ‘targeted worming’ is so important.

To find out more about wormers, types of worms, and the symptoms each parasite could cause, please visit our guide to worming horses.

What is targeted worming?

Essentially, targeted worming means that we only give our horses wormer products when there’s evidence that they need it. That way, we’re lowering the risk of worms becoming resistant to the worming products, because our horses aren’t exposed to those active ingredients as often. 

To determine whether our horses need worming or not, we monitor them regularly and don’t give them wormer if there’s no sign of worms. There are tests available that allow us to check whether our horses would benefit from worming, such as faecal worm egg counts (FWEC), saliva tapeworm tests, and blood tests.

We’ll explore the types of testing available for targeted worming later in this article, though a targeted worming programme also requires non-chemical management practices, in order to be effective. 

Remember: Every horse is unique, so you should always speak to an equine vet for advice about the best targeted worming strategies for your horse.

Natural management practices for targeted worming 

Alongside testing your horse and following your vet’s advice about worming, here are some of the management practices to put in place at your yard, to improve worm control:

• Ensure there’s enough field space for the number of horses – for example, at least one to one-and-a-half acres per horse.
• Poo-pick paddocks and fields every day, where possible – though at least twice a week.
• Cross-graze paddocks and fields with other species, like sheep, who can help to safely clear some of the parasites that pose a danger to horses.
• Rotate paddocks and fields to allow the ground to ‘rest’ – to prevent overgrazing, which can increase the risk of worms.
• Avoid using horse manure to fertilise fields used for grazing.
• Quarantine any new horses who arrive at the yard, by not allowing them to be turned out with others until they’ve been tested for worms (and successfully de-wormed, if required).
• Due to the serious threat parasites pose to a foal’s health, only turn foals out onto fields that have been rested for six months. 

Please note: It’s beneficial for all horses on a yard if their owners follow the same targeted worming programme.

Types of testing available for targeted worming

Testing your horse for parasites is a crucial part of developing a successful targeted worming programme. 

While there are several different types of tests available, here are the three most common tests you’re likely to use for your horse:

FWEC (Faecal Worm Egg Counts)

Faecal worm egg counts, commonly known as ‘FWEC’, provide an estimate as to the amount of small redworm, large redworm, and roundworm eggs that are present in your horse’s poo. 

Your vet will advise as to when you should be performing FWECs, though generally, faecal worm egg counts should be carried out through the spring and autumn months. 

The process for collecting and sending off a FWEC is simple…

Step 1 – Write your horse’s details on the label of the FWEC pot provided by your vet (which could arrive in the post if you don’t live near an equine vet practice).

Step 2 – Wearing a pair of disposable gloves, collect a small amount of poo from a fresh sample of your horse’s droppings by putting it into the pot. 

Top tip: Collect tiny pieces of poo from more than one nugget, to get a better idea of your horse’s worm count!

Step 3 – Send your horse’s poo sample within 24 hours of it being collected, which can usually be done by handing the sample into your equine vet practice or via post. For best results, please keep your horse’s sample at a cool temperature.

Top tip: Try sending all FWEC samples from your horse’s herd at the same time, as that’ll make it easier to manage your yard’s targeted worming programme!  

Step 4 – Await the results of the FWEC analysis and follow your vet’s advice as to whether your horse requires worming treatment or not.  

Saliva tapeworm test

A saliva tapeworm test measures the tapeworm antibodies that are present in your horse’s saliva. This type of test allows your vet to diagnose a tapeworm burden as well, which empowers both you and your vet to act quickly if your horse has tapeworm. 

You can usually collect saliva testing kits from your equine vet (or have them sent via post), though some manufacturers also sell them directly to horse owners.  

To take a saliva tapeworm test, follow these steps:

Step 1 – Make sure your horse hasn’t been exercised and hasn’t had anything to eat or drink for half an hour before taking the sample, to help get more accurate results. 

Step 2 – Put a headcollar onto your horse, so it’s easier to encourage them to keep their head still while you’re taking the test.

Step 3 – Hold the cotton swab (that’s provided in the testing kit) just inside your horse’s mouth, where the bit would sit, for 30-120 seconds. When you’ve collected enough of your horse’s saliva, the indicator at the end of the tube should change colour. Then, praise your horse for being so co-operative!

Step 4 – Once the sample is ready, carefully place it into the tube (which should contain a solution to help preserve the sample). Write your horse’s information on the label of the outer tube, before placing it into the bag that’ll be sent off by post or given to your vet. 

Blood testing

Another way to find out if your horse is suffering from a worm burden is through a blood test. 

The optimum times to book a blood test for your horse to assess them for parasites would be during the autumn and winter months. However, your vet should be able to advise what’s best for your horse and whether a blood test is needed.

Blood testing can provide the following information about your horse:

• Diagnosis of a cyathostomin infection caused by small redworm.
• Measurement of tapeworm antibodies present in their blood.

Only an equine vet will be able to perform a blood test on your horse.

Example of a targeted worming programme

An example of a simple targeted worming programme:

• Spring (March – May) = FWEC in April.
• Summer (June – August) = FWEC in July.
• Autumn (September – November) = tapeworm saliva test in October.
• Winter (December – February) = FWEC in January.

Then, give your horse a worming product appropriate to the type of parasite found, if their test results suggest they have a high number of worms. 

Don’t forget! Although it’s essential to follow worm management practices every day (like poo-picking paddocks), you’ll need to discuss your horse’s targeted worming programme with an equine vet before implementing it. 

Your horse’s risk profile for targeted worming

To create a targeted worming programme for your horse, it’s helpful to assess their parasite risk profile. 

A parasite risk profile includes a range of factors that will impact the likelihood of your horse suffering the negative effects of a worm burden. 

Thankfully, a group who works in the interest of UK equines, called CANTER, has created a helpful acronym to support horse owners to understand risk factors involved in targeted worming: 

C – Clinical history

Your horse’s health will play a role in whether they’re at a low, medium, or high risk of worms. For example, a horse in the low-risk category wouldn’t have history of worm-related health problems – whereas a horse in the high-risk category may have a history of worm-related gut issues.

A – Age profile

Age is another significant factor when considering the severity of risk surrounding worms in horses. For instance, a horse aged less than five years and older than 20 years would be considered at greater risk than a horse between five and 20 years old.

N – Number of horses

The number of horses sharing a field will have an impact on the risk of parasites. For example, if there are two acres or more per horse, that’s considered low-risk – while having less than one acre per horse would put them into the high-risk category. 

T – Test results

Results from a horse’s parasite tests, e.g. FWEC, will help to determine whether they fall into the low, medium, or high risk category. 

E – Environment

Environment is an important factor in your horse’s parasite risk profile. For instance, horses who are kept in a field that’s poo-picked daily, on a yard with effective quarantine procedures in place, will likely be in the low-risk category.
 
R – Risk profile calculation

Using answers to the above can assist you and your vet in working out which category your horse fits into. 

Generally, horses who are recorded as primarily low risk will have lower susceptibility to worm burden. This empowers you, as an owner, to take action to manage your horse’s targeted worming programme effectively. For example, a yard that frequently moves new horses into and out of a herd could put quarantine procedures in place to reduce the risk of worms. 

Please note: Since each horse is an individual, there may be horses who don’t fit the high or low risk profiles yet test differently. For instance, a horse whose management fits into the ‘low risk’ category (e.g. they’re in a small herd on pasture that’s poo picked daily) could still be considered ‘high risk’ if they consistently get high FWEC. In these situations, it’s always best to discuss your horse’s care and worming needs with a vet, who can offer advice that’s specific to your horse’s circumstances.   

Benefits of a targeted worming programme

A targeted worming programme offers plenty of benefits, including:

• Protecting your horse from the harm caused by worm burdens. 
• Reducing parasite resistance to active ingredients in wormers.
• Saving you money on buying wormers your horse doesn’t need!

For further advice on ways to keep your horse happy and healthy through every chapter of their life, you can read our horse health guides and horse safety articles.