Faecal worm egg counts – keep track of your horse’s worm burden

By Thomas Tzelos on 25 September 2020

Why all the fuss about faecal worm egg counts?

HorseDialog’s guest vlogger Dr Thomas Tzelos of the Moredun Research Institute, Scotland takes us into the laboratory to explain why it pays to keep counting.

Follow our checklist to keep your horse healthy:

  • Count from early spring to late autumn: Conducting regular faecal worm egg counts (FWECs) during the main grazing season will save worming horses unnecessarily which helps to prevent the build-up of resistance to wormers.1
  • Keep grazing clean: Regular removal of droppings from the field will help prevent horses ingesting worm eggs passed in dung and re-infecting themselves or their field companions.2
  • Don’t forget - encysted small redworm and tapeworm won’t show up in a faecal worm egg count In the late autumn/winter, treat or test for encysted small redworm and tapeworm. This should be repeated roughly every six months for tapeworm and at least annually for ESRW3,4,5
  1. Rendle D (2017) De-worming targeted plans. Vet Times, Equine, Vol.3 Issue 1 p16-18
  2. Matthews JB (2017) Helminth control programmes for equine yearlings at pasture. Veterinary Times; 47(8):22-22, 24.
  3. Austin Davis Biologics Ltd. Small Redworm Blood Test Press Release.https://www.austindavis.co.uk/small-redworm-blood-test. Accessed 11th October 2019
  4. Proudman CJ (2003) Journal of Equine Veterinary Science 23 (1) 6-9
  5. Austin Davis Biologics Ltd: Elisa Kits. https://www.austindavis.co.uk/elisa-kits. Accessed 8th April 2020




Thomas qualified from Aristotle University of Thessaloniki, Greece, in 2009 and moved to Edinburgh to undertake an MSc in applied animal behaviour and animal welfare. In 2011 he moved to the Moredun Research Institute to undertake a PhD focusing on the application of RNA interference in the ovine nematode Teladorsagia circumcincta. Since January 2015, he has been working as a post-doctoral researcher at Moredun Research Institute in the field of Equine Parasitology.

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