Large Strongyle Larval Culture Test

Large strongyles (Strongylus species), also known as large redworm, are among the most dangerous parasites affecting horses—capable of causing life-threatening colic and severe internal damage. While now rare, they can re-emerge if left unchecked, particularly with more targeted worming approaches.

This test is strongly recommended once a year for:

• Larger yards and studs
• Competition and training horses
• Properties with frequent horse movement, especially from overseas

Used alongside regular worm egg counts and tapeworm testing, larval culture offers a cost-effective method for routine monitoring of large strongyle infection.

How it works:

• Submit individual or composite samples (up to 4 horses)
• We culture strongyle eggs from a faecal sample over 10–14 days to identify the presence of Strongylus vulgaris, S. edentatus, and S. equinus. N.B. Small redworm (cyathostomins) are not reported due to the large number of species and their overwhelming presence in most samples. A worm egg count is recommended alongside this test to determine the eggs per gram (EPG) and assess whether treatment for small redworm is necessary.
• Ideal grouping: horses that graze or live together

Best testing time: Spring to early summer (March–July), when larvae return to the gut to produce eggs

Can be used year-round if symptoms suggest infection

Turnaround time: Please allow two weeks from the sample’s arrival at the lab.