Internal Parasites - Worms

Main parasites of concern

  • Red worms (most common) – Strongylus group

  • Threadworms (Strongyloides westeri)

  • Roundworms (Parascaris equorum, most common in foals)

  • Tapeworms (Anoplocephala perfoliata)

  • Pinworms (Oxyuris equi)

  • Bots (Gasterophilus intestinalis)

Worming resistance is a growing issue amongst horses in Australia. To prevent resistance, we recommend the following worming management and protocol:


  • 3 – 4 faecal egg counts should be performed per year with treatments targeted at animals with high faecal egg counts

  • Treatment should be performed during seasons of peak transmission (Spring and Autumn) where possible.

  • Consider the individuals risk for parasite related disease when developing an appropriate worming program

  • An effective tapeworm treatment should be given annually to all horses, regardless of their FEC. This should be performed in late autumn or winter

  • 1 – 2 treatments per year to control large Strongyles and Bots

Young horses

Foals and horses less than 3 years of age are susceptible to infestation and worm-related disease and therefore require special consideration. Foals should receive four anthelmintic (antiparasitic) treatments in the first year of life.

  • 2 – 3 months old – first worming with a benzimidazole containing product

  • 4 – 6 months old – faecal egg count just prior to weaning and treatment based on results

  • 9 months old – treatment to target Strongyles and tapeworm

  • 12 months old – treatment to target Strongyles

  • Yearlings and 2-year-olds are considered high shedders and should be treated approximately 3 times a year based on faecal egg count results

Chat with your vet about an appropriate worming schedule for your horse.