Worm egg count for horses: samples and results

Choosing a test and planning the year

Check what a kit includes before ordering: the parasites and stages it can detect, the collection pot, return postage, laboratory result and access to advice. A standard worm egg count primarily finds eggs from adult strongyles and ascarids; it does not cover every parasite. Ask the laboratory how to sample each horse, store the sample and avoid postal delays.

Young horses, new arrivals and horses with illness need their own plan. A schedule used for a healthy adult should not be copied to them. In the UK, use the CANTER risk assessment with your vet or qualified prescriber. A selective programme uses repeated results to target some treatments; strategic control also addresses risks not resolved by one routine count.

What the result means

EPG means eggs per gram of dung. It describes egg shedding at sampling, not total parasite burden. Encysted small strongyles and other parasite stages are not excluded by a low count. Illness requires veterinary assessment rather than waiting for a routine test.

Prepare a sample

• Ask your vet or laboratory which test and container are appropriate.
• Collect fresh dung known to come from the correct horse, following their instructions.
• Label the horse, collection date and time, and recent treatment.
• Follow the test-specific storage temperature and shipping deadline.
• Keep the complete result, unit and laboratory name.

From result to an agreed plan

Your vet decides whether treatment, another test or later monitoring is appropriate. Drug, dose and post-treatment testing depend on the horse and test purpose. Do not copy one threshold or calendar to every horse. UK guidance comes from CANTER; US guidance comes from AAEP and includes baseline treatment as well as selective extra treatment.

What to record

Records support the discussion; an app does not choose treatment.

When is another test needed?

An egg count does not diagnose clinical disease. Colic, diarrhoea, weight loss or lethargy needs veterinary assessment even after recent treatment.

Keep a complete parasite-control record

• Identify the horses and grazing areas covered by the plan, including separate arrangements for youngstock and new arrivals.
• Remove dung regularly and keep stables and feeding areas clean. Discuss grazing density and pasture management; medication alone cannot prevent reinfection.
• Check weight, product and prescribed amount with the professional responsible. Do not guess doses or rotate products yourself.
• Retain the original laboratory report and record the prescribing decision separately.
• Agree any efficacy check and the next test before treating the current episode as complete.
• Do not replace a prescribed wormer with a herbal product or supplement.