Worming: Faecal Worm Egg Counts (FWEC)
Why do I need to do this test?
Faecal worm egg counts detect eggs of strongyle type worms such as large redworms, small redworms and roundworms, but not tapeworms.
Regular faecal worm egg counts throughout the grazing season will help to assess whether your horse needs to be wormed. By only worming your horse when you need to will help to reduce resistance to the drugs used in wormers and is better for your horse. We need to do all we can to reduce resistance to wormers as, if we do not take these steps, wormers will cease to work effectively in the future.
What does the result mean?
It is generally recommended that you worm your horse if the result is 200 eggs per gram or above. Your vet will be able to give you advice on a suitable wormer.
If the result is under 200 eggs per gram, you will probably not need to worm your horse.
It is important to continue with regular faecal worm egg counts throughout the grazing season (approx. every 12 weeks) as the worm life cycle includes larval stages that are not detected from a faecal worm egg count.
As faecal worm egg counts do not identify all types of worm, it is important to carry out a test for tapeworm and a worm risk assessment (usually in the autumn/early winter) to establish whether your horse needs to be treated for tapeworm and/or encysted small redworm larvae.
https://www.horsehealthprogramme.co.uk/risk-assessment-for-parasite-control-in-horses/