What do the results of my horse's faecal egg count mean and what does a worm count test for? For each horse on the result sheet there will be a number indicating the level of worm eggs found.
Which worms are covered by a faecal egg count test?
Usually your result will say STRONGYLE EGGS. This is a collective term for small and large redworm, the most common parasites that affect horses. Worm egg counts show all but encysted stages of redworm as these are not mature so don't lay eggs to be counted in the dung sample. It is important to treat these with an effective product in the winter months (Dec-Feb) then you can rely on worm counts for the remainder of the year.
Worm egg counts are not a definitive test for TAPEWORM EGGS, although though these don’t always show on a count. Your horse could still have tapeworm even if no eggs are seen. Use the Equisal saliva test for tapeworm twice a year for a reliable way to monitor tapeworm infections.
We may find ASCARIDS. This is roundworm, usually only a problem in foals and previously neglected horses. Any sign of these requires treatment usually. The old fashioned drugs such as Pyrantel & Fenbendazole have the least resistance for ascarids treatment but if not sue please get in touch.
What should I do now?
Equine worm egg count results explained
Worm egg count results are given in eggs per gram to the nearest 25 (e.p.g)
Have you considered tapeworm in the last 6 months? If not consider EquiSal testing for it now please. If you have tapeworm tested please await those results before dosing as you may need a combination wormer.
Worm egg count results (looking for adult egg laying redworm & roundworm)
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The sign < means ‘less than’, so a result of<50 e.p.g means no eggs seen in the sample. If you have a 25 e.p.g reading this is the lowest level of redworm we can see and no treatment needed. Have you considered tapeworm in the last 6 months? If not and med/high risk then please EquiSal test now. |
Up to 175 e.p.g means a LOW redworm count and your worming measures are working to keep the burden lower. Assuming you wormed with Equest in the winter no treatment now unless your horse is under 4 years old where you'd worm now with Strongid-P please. Any roundworm warrants treatment even if over 4 use Strongid-P. Moxidectin & ivermectin don't treat it effectively now due to resistance. |
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Between 200 e.p.g and 1175 e.p.g is a MEDIUM redworm count, the horse needs worming with an ivermectin now (assuming horse hasn't had ivermectin in the Spring, if so use Strongid-P now) and possibly reduction test 10-14 days on to check for resistance.
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Over 1200 e.p.g is a HIGH redworm count, the horse needs worming with an ivermectin and the pasture management needs attention also. Ensure poo picking is being carried out at least twice a week and muck heap is not in the field. Please reduction test 10-14 days on to check for resistance.
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Equest is suitable for most horses including pregnant mares but please ensure they have sufficient bodyweight as it's stored in the body fat so its not always suitable for very lean or rescue horses.
The worm egg count is looking for adult egg laying redworm and roundworms so does not always mean the animal is worm free so please see below table for guidance as to what to do when for equines regarding testing. If tapeworm eggs are shown in your worm egg count then you need to treat for that with either praziquantel only from the vet if no redworm shown or ivermectin/praziquantel if you need to treat both redworm & tapeworm.
Reduction test results - To work out how affective your worming has been use the reduction test result and divide it by your original worm egg count result and then multiply by 100. This tells you the percentage of worms that have not been killed by the product used. Anything over 15% would warrant further treatment with a different drug but please get in touch if you need more clarification.
Reduction test result/original worm egg count result x 100 = % of worms not killed by product used
For a wormer to go to market it needs to be more than 95% effective against the worms it is licenced to kill – but with regular treatment resistance on the pasture grows and egg reappearance times (as dictated in the drug’s data sheet) begin to diminish over time. This means the usefulness of a drug against a specific parasite species can be measured:
- After a positive worm egg count for redworm or roundworm that requires treatment, conduct a second worm egg count 10-14 days after worming.
- After a positive EquiSal saliva test for tapeworm treat with a recommended drug and test again 12 weeks later.
If sufficient dose has been administered correctly for the weight of the animal and the follow-up test is showing a reduction of less than 95% efficacy to the targeted parasite(s) then some resistant worms are present. For example a medium worm egg count between 200 and 1150 e.p.g. should reduce to <50 epg and a high worm egg count of 1200 e.p.g .should reduce to less than 100 e.p.g. on a follow-up test to not be classed as resistant.
Pinworm test results- A negative result simply means that no eggs were detected at the time the test was taken, it doesn't mean that there are no pinworm present in your horse.
If you still suspect a problem you may want to test again, keeping an eye out for other symptoms in the meantime such as tail rubbing, beansprout type worms in droppings or signs of the sticky substance the eggs are laid in around the anus which can be a yellow/orange colour. Pinworm treatment if positive is usually the older chemicals such as fenbendazole or pyrantel.
More info here as to what to do after worming.
If you need any further help with your result, worming programme or worming in general please do not hesitate to get in touch and we will do our best to answer your questions. If you have any concerns about your horse’s health then you should consult your vet.
How long does it take to get results?
We aim to test the faecal worm egg count samples on the day they arrive and your results will be sent promptly by email or text usually. The post can take anywhere between 1-6 days to reach us. If you sample arrives after 6 days we will be in touch to retest as it will be too old for an accurate result.