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Equine Spring/Summer Worming Guide



During the spring and summer months, conducting faecal worm egg counts will help to identify those horses that may require administration of a suitable wormer.
Time it right this spring/summer.

Click Here to order your Worm Egg Count Kits

In the wild, horses used to roam freely over thousands of acres, with continuous access to clean and fresh pasture. Worms and horses evolved together in this environment, developing a relatively healthy balance to maintain both populations.

As domesticated horses are kept on more restricted grazing, they have limited opportunity to move onto cleaner pasture and this exposes them to worm re-infection at a much greater level, upsetting the horse/worm balance.

Breaking the life cycle of parasites reduces the amount of worm challenge our horses face. Eggs are passed in the droppings, where they develop into larvae and contaminate the pasture ready to be eaten by grazing horses. An essential part of breaking the cycle is reducing the number of these stages on the pasture, keeping the number of larvae that a horse eats (challenge) to a minimum. In turn, managing the pasture can also reduce our reliance on wormers, reducing the drive for wormer resistance.

Pasture Management Top Tips
  1. Regularly remove horse droppings from your pasture (at least twice a week)
  2. Graze the pasture with cattle or sheep
  3. Rest the pasture
  4. Combine harrowing with resting
  5. Try not to over stock paddocks

A typical horse, weighing 450 kg, produces 5 to 12 pats, approximately 24 kg of dung a day or 10 tonnes a year!

What are faecal worm egg counts (FWECs)?
FWECs measure the number of worm eggs in your horse’s dung and gives an indication of how much your horse’s worm burden is contributing to pasture contamination.

Tapeworm Antibody Test
This is a blood or saliva test that identifies tapeworm exposure by measuring antibody levels.

Test Results
Depending on the results of your horse’s FWEC or tapeworm test you may be advised to treat or re-test at a future date.

Which Test Should I Use?

Faecal Worm
Egg Count
Antibody Test
Adult small redworm
Adult large redworm
Large roundworm
Encysted small redworm



  • During the spring and summer, a FWEC can be used to guide appropriate dosing for redworm
  • The interval between FWECs is variable depending on the horse’s individual circumstances; however, every 2–3 months is a good place to start1
  • If a FWEC is > 200 eggs per gram treatment may be recommended2

Foals and young horses (< 3yrs of age) usually require a different approach. Speak to your vet or SQP for specific advice.

New Horses
New horses with an unknown worming history should be quarantined, FWEC tested and treated for tapeworm and encysted small redworm on arrival. They should then be stabled for at least 48 hours to avoid bringing resistant worms onto your premises3.

  1. Ensure you have treated for encysted small redworm over the autumn/winter period – if not, treat now!
  2. Ensure treatment or test for tapeworm within the previous 6 months
  3. Conduct FWECs throughout the grazing season to identify those horses that need administration of a wormer
  4. Remember to remove droppings from the pasture daily
  5. Use a weigh tape or weigh bridge to dose accurately if treatment is required. This is important because under-dosing can increase the risk of resistance development. Horses should be dosed accurately, according to their weight.