Evaluation of Strategies to Reduce Equine Strongyle Infective Larvae on Pasture and Study of Larval Migration and Overwintering in a Nordic Climate.
Authors: Osterman-Lind Eva, Hedberg Alm Ylva, Hassler Hillevi, Wilderoth Hanna, Thorolfson Helena, Tydén Eva
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Strongyle resistance to anthelmintics is now widespread, forcing practitioners to reconsider pasture management as a cornerstone of parasite control rather than relying solely on pharmaceutical intervention. This Swedish study evaluated faecal removal frequency and harrowing as practical pasture-management strategies, whilst simultaneously characterising larval survival and migration patterns under Nordic climatic conditions—data critical for designing realistic control protocols in temperate regions. Twice-weekly faecal removal proved significantly effective at reducing larval yields on herbage, whereas single harrowing during dry summer conditions failed to achieve meaningful reduction, suggesting this labour-intensive approach offers limited return on investment for most operations. The capacity of both Cyathostominae and *Strongylus vulgaris* larvae to survive 17–18 months on pasture and migrate up to 150 cm from faecal pats underscores the extended transmission risk across grazing seasons; whilst one year of pasture rest achieved partial parasite suppression, complete elimination required two years of complete rest. For practitioners seeking to reduce anthelmintic dependency, these findings support intensified dung management as immediately actionable, whilst emphasising that effective strongyle control in cool climates necessitates either rotational grazing systems with extended fallow periods or continued judicious use of targeted anthelmintics alongside improved pasture hygiene.
Read the full abstract on PubMed
Practical Takeaways
- •Implement twice-weekly faecal removal from pastures as an effective non-chemical strategy to reduce strongyle exposure and anthelmintic dependency
- •Single harrowing is ineffective as a parasite control method; focus efforts on faecal removal instead
- •Allow 2 years of pasture rest for complete parasite elimination in Nordic climates, accounting for extended larval survival through winter months
Key Findings
- •Twice-weekly faecal removal significantly reduced larval yields on pasture
- •Single harrowing under dry summer conditions did not effectively reduce larvae
- •Strongyle larvae migrated up to 150 cm from faecal pats with concentration within 50 cm
- •Both Cyathostominae and S. vulgaris survived Nordic winters with larvae viable 17-18 months after deposition
- •One year pasture rest substantially reduced parasite levels; two years required for parasite-free pasture