Unravelling the Effectiveness of Anthelmintic Treatments on Equine Strongyles on Irish Farms.
Authors: Elghryani Nagwa, Lawlor Amanda, McOwan Trish, de Waal Theo
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Anthelmintic resistance in equine strongyles has become a significant concern across Irish grazing operations, prompting Elghryani and colleagues to assess the current prevalence and severity of resistance on 44 farms using faecal egg count reduction (FECR) testing via mini-FLOTAC methodology. Benzimidazole resistance was alarmingly widespread, detected on 12 of 14 farms tested with FECR values ranging from complete treatment failure (0.00%) to partial efficacy (86.2%), whilst ivermectin and moxidectin resistance, though less prevalent, was confirmed on two and three farms respectively, with some borderline cases falling below the acceptable 90% efficacy threshold. These findings reveal that practitioners can no longer rely on conventional anthelmintic regimens as standalone parasite management tools on many Irish operations, and strategic rotation or combination therapy approaches require urgent reassessment. For farriers, vets, and nutritionists involved in equine care, this data underscores the critical importance of implementing targeted grazing management, pasture rotation, risk-based treatment protocols, and regular FECR monitoring to preserve anthelmintic effectiveness and slow the trajectory toward multi-drug resistant strongyle populations. The study reinforces that evidence-based parasite control strategies—prioritising non-chemical interventions and judicious drug use—are now essential components of professional equine health management planning.
Read the full abstract on PubMed
Practical Takeaways
- •Benzimidazole resistance is widespread on Irish farms; your farm is likely affected—request FECR testing via mini-FLOTAC before relying on these drugs
- •While ivermectin and moxidectin remain largely effective, emerging resistance on individual farms means drug choice should be evidence-based, not routine; consider rotation and targeted selective treatment protocols
- •Shift management focus to pasture hygiene, grazing management, and selective deworming of high-burden animals to slow resistance development and preserve drug effectiveness
Key Findings
- •Benzimidazole resistance detected on 86% of surveyed farms (12/14 farms tested), with FECR ranging from 0–86.2%
- •Ivermectin resistance identified on 2 farms with FECR of 80.7% and 96.1%, though 6 other farms maintained >95% efficacy
- •Moxidectin reduced efficacy noted on 3 farms with FECR values of 86.9%, 93.5%, and 99.5%
- •Multi-drug resistance patterns indicate urgent need for non-anthelmintic parasite management strategies on Irish equine farms