Today, the focus is increasingly on testing first, treating when necessary and making better-informed dosing decisions.

At Feirm Supplies, we make that easier.

We provide faecal egg count testing for worms and fluke, carried out quickly in-house in our own laboratory, helping Irish farmers get the information they need to make more targeted parasite-control decisions.

Less guessing. Better information. More targeted treatment.

What is a faecal egg count?

A Faecal Egg Count (FEC) is a laboratory test carried out on a dung sample to identify and measure parasite eggs being shed by an animal.

For gastrointestinal or stomach worms, the result is generally expressed as the number of eggs per gram (EPG) of faeces.

The result provides an indication of the level of worm infection within the animals or group being tested and can help determine whether treatment should be considered.

Faecal samples can also be examined for liver and rumen fluke eggs, although fluke testing needs to be interpreted differently from a standard worm egg count.

Animal Health Ireland identifies faecal testing as a useful tool for monitoring parasites, investigating animals that are failing to thrive, deciding whether worm treatment is needed and assessing how effectively a wormer is working.

Why should farmers carry out faecal egg count testing?

The simple answer is:

Because you cannot tell what the parasite burden is simply by looking at an animal.

Animals can appear healthy while carrying parasites, while poor thrive or reduced performance can have many different causes.

Testing gives you more information before reaching for a wormer.

A faecal egg count can help farmers:

• Identify whether there is evidence of a worm burden
• Make more targeted dosing decisions
• Reduce unnecessary worm treatments
• Monitor parasite levels during the grazing season
• Investigate poor thrive or reduced performance
• Assess pasture parasite pressure
• Check whether a previous worm treatment has been effective
• Build a more sustainable parasite-control programme

Teagasc describes carrying out a faecal egg count before dosing as best practice in cattle because it can minimise unnecessary use of dosing products and help reduce the risk of anthelmintic resistance developing on farm.

In other words: test before you dose.

Why is wormer resistance becoming such an important issue?

One of the biggest reasons for moving towards targeted parasite treatment is anthelmintic resistance, commonly referred to as wormer resistance.

Anthelmintic resistance occurs when parasites survive a dose of a treatment that would normally be expected to kill them.

Over time, repeated or inappropriate use of wormers can increase the proportion of resistant parasites on a farm.

Eventually, a product that farmers previously relied upon may no longer provide adequate control.

The Department of Agriculture, Food and the Marine warns that antiparasitic resistance threatens animal health and welfare as well as the sustainability and profitability of Irish cattle and sheep farming.

That is why the message is changing from:

Dose because it is that time of year.

to:

Test, assess and treat when required.

Is the wormer you are using actually working?

Faecal egg counts aren't only useful before treatment.

They can also be used as part of a programme to assess whether a worm treatment is still working effectively on your farm.

This matters because wormer resistance is not always obvious.

Animals may have been dosed correctly and yet parasites may still survive.

Teagasc's work on anthelmintic resistance highlights that testing is an important way of establishing whether wormers remain effective on individual farms.

A test-and-retest approach therefore gives farmers much more information than simply assuming the treatment has worked.

Why should I retest?

A faecal egg count is a snapshot in time.

Parasite burdens can change throughout the grazing season depending on factors including weather, pasture contamination, grazing management, animal age and previous exposure.

Animal Health Ireland points out that even a zero FEC result does not necessarily mean an animal has no worms. Parasites may be present but at a stage of their lifecycle where they are not yet producing eggs.

This is why repeat testing can be so valuable.

The Feirm Supplies Worm & Fluke Test and Retest Kit includes:

4 sample vials

2 for your initial test 2 for retesting 6–8 weeks later

It also includes the information required for submitting the samples and instructions for returning them for testing.

Retesting helps you build a clearer picture of how the parasite challenge is changing rather than basing your entire dosing programme on one result.

Can a faecal egg count detect liver fluke?

Yes – but there is an important limitation farmers need to understand.

Faecal testing can identify eggs produced by mature adult liver fluke.

However, immature liver fluke do not yet produce eggs.

This means a negative dung test does not automatically rule out an early or immature liver fluke infection.

Teagasc advises that faecal egg testing generally identifies adult fluke once they have reached the stage at which they are producing eggs, which may be approximately 10–12 weeks after infection.

Fluke can also shed eggs intermittently, which is another reason why results need to be interpreted alongside factors such as:

• Farm history
• Grazing conditions
• Previous fluke problems
• Time of year
• Clinical signs
• Factory liver reports
• Veterinary advice

So while faecal testing is a useful part of a liver-fluke control programme, it should not be viewed as a guarantee that immature fluke are absent.

Why are worms and fluke important for cattle and sheep performance?

Parasites are not simply a dosing problem.

A significant parasite burden can affect animal health, welfare and farm performance.

Gut worms can contribute to poor thrive and reduced growth, particularly in younger grazing animals.

Liver fluke can cause liver damage, loss of condition and other health and performance issues.

The challenge is that production losses can begin before severe clinical signs become obvious.

That makes monitoring valuable.

Rather than waiting until cattle or sheep visibly lose condition, regular parasite testing can form part of a more proactive herd or flock health programme.

Do cattle and sheep need to be routinely wormed?

Not necessarily.

Parasite risk varies significantly between farms, groups of animals and different stages of the grazing season.

Older cattle and sheep that have developed immunity to certain stomach and gut worms may have very different treatment requirements from first-season grazing animals.

Weather conditions, pasture history, stocking density and grazing management can also affect the parasite challenge.

That is why a one-size-fits-all dosing programme is increasingly difficult to justify.

Testing helps provide evidence for the decision.

What has changed with worm and fluke treatments in Ireland?

Parasite control has also become increasingly important because of changes to veterinary medicine regulation in Ireland.

From 1 December 2025, antiparasitic veterinary medicines for food-producing animals moved to prescription-only medicine status in Ireland.

The Department of Agriculture has linked this change directly to concerns surrounding antiparasitic resistance and the need for more prudent use of these medicines.

This does not mean a faecal egg count replaces veterinary assessment or a veterinary prescription.

Instead, FEC results can provide useful evidence to support a more informed discussion about parasite control and whether treatment may be necessary.

The direction of travel is clear:

Treat parasites based on evidence — not simply habit.

Fast Faecal Egg Count Testing at Feirm Supplies

One of the biggest frustrations with testing can be the time between taking a sample and getting useful information back.

At Feirm Supplies, we carry out our faecal egg count testing in-house in our own laboratory.

That allows us to provide farmers with a simple, practical service designed around making parasite monitoring easier.

How it works

1. Order your testing kit

Choose your Feirm Supplies Worm Test or Worm & Fluke Test and Retest Kit.

2. Take your samples

Collect fresh dung samples following the instructions supplied with your kit.

3. Return your samples

Send or return the samples to Feirm Supplies using the supplied instructions.

4. We test them in-house

Your samples are analysed in our laboratory rather than the process being unnecessarily complicated for the farmer.

5. Get your results

Use the results to help make a more informed parasite-control decision.

6. Retest

Use the additional sample vials supplied with the test-and-retest kit to monitor how the situation changes.

Why choose Feirm Supplies for faecal egg count testing?

In-house laboratory testing

Samples are tested directly through our laboratory, helping us provide farmers with a straightforward and efficient service.

Worm & fluke testing

Testing options are available to help monitor both gastrointestinal worms and fluke.

Test and retest

Our Worm & Fluke kit includes samples for an initial test and a follow-up test 6–8 weeks later.

Built for Irish farms

The service is designed around the practical needs of Irish cattle and sheep farmers.

More than just a test

Feirm Supplies can also support farmers with their wider animal-health and parasite-control requirements.

When should you consider carrying out a faecal egg count?

Testing can be particularly useful:

• During the grazing season
• Before deciding whether to worm
• When animals are failing to thrive
• Where weight gain is below expectations
• Where there is a history of worm problems
• When you are concerned a wormer may no longer be effective
• When developing a parasite-control programme
• When monitoring young grazing cattle or lambs
• When investigating possible liver-fluke exposure
• As part of an ongoing herd or flock health plan

The ideal timing will depend on the animals, farm and parasite being investigated.

Frequently Asked Questions

What is a faecal egg count?

A faecal egg count or FEC is a laboratory examination of a dung sample used to detect and quantify eggs from gastrointestinal worms. Results are commonly reported as eggs per gram of faeces.

Why should I test before worming cattle or sheep?

Testing can help determine whether treatment is actually required. This can reduce unnecessary dosing, lower selection pressure for wormer resistance and provide a more targeted approach to parasite control.

Can a faecal egg count detect liver fluke?

Faecal testing can detect eggs from mature adult liver fluke. It cannot reliably rule out immature liver fluke because immature parasites are not yet producing eggs.

Does a zero faecal egg count mean my animals definitely have no worms?

No. A FEC is a snapshot at a particular point in time. Parasites can be present before they have matured sufficiently to produce detectable eggs, so repeat testing may be necessary.

Can FEC testing tell me whether my wormer is working?

Faecal egg counts taken before and after treatment can form part of a Faecal Egg Count Reduction Test (FECRT), which is used to assess the effectiveness of wormers and investigate possible resistance. The correct timing of the post-treatment test depends on the product used, so veterinary or laboratory guidance should be followed.

Does a standard worm FEC test detect lungworm?

Not necessarily. Lungworm requires a different laboratory testing method and should be specifically investigated where it is suspected. A standard gastrointestinal worm egg count should not be used to rule out lungworm.

Can I test both cattle and sheep?

Yes. Feirm Supplies' FEC testing service is suitable for parasite monitoring in both cattle and sheep.

Where are Feirm Supplies' samples tested?

Samples are tested in-house through our laboratory at Feirm Supplies, helping us provide a quick and straightforward service to farmers.

Stop Guessing. Start Testing.

Every unnecessary treatment adds cost.

Every ineffective treatment leaves a problem behind.

And every time we use a wormer unnecessarily, we increase the selection pressure that can contribute to resistance.

Faecal egg count testing gives you information before you make the decision.

Test first. Treat when needed. Retest and monitor.

With fast, in-house worm and fluke testing from Feirm Supplies, getting a clearer picture of what's happening in your herd or flock couldn't be simpler.

Order your Faecal Egg Count Worm & Fluke Test and Retest Kit from Feirm Supplies today.

Internal link: https://feirmsupplies.com/category/veterinary-animal-care/dosing-vaccines/worm-testing

Need help? Call the Feirm Supplies team on (053) 923 6240.

Faecal egg count results should be considered alongside animal health, farm history and veterinary advice. Testing does not replace veterinary diagnosis or a veterinary prescription where one is required.