Effectiveness of eprinomectin, albendazole and their combination therapy against strongyle nematode in dairy goats: A clinical field study using nemabiome-integrated approach in Thailand.

Strongyle nematodes are parasitic worms that significantly impact the health and productivity of livestock, including goats. Although infected goats are commonly treated with anthelmintics, reports of anthelmintic resistance have been increasing. This issue, along with limited treatment choices for goats and the lack of comprehensive anthelmintic resistance surveillance in Thailand, highlights the need to evaluate available drugs for effective parasite control. On a dairy goat farm in Chiang Mai, Thailand, a previous fecal egg count reduction test (FECRT) revealed resistance of strongyle nematodes to ivermectin, one of the most widely used anthelmintic drugs in the country. To further investigate treatment options, a clinical field study was conducted using the FECRT to evaluate the efficacy of eprinomectin at the label dose (0.2 mg/kg, n = 15 goats) and double dose (0.4 mg/kg, n = 9 goats), albendazole (20 mg/kg, n = 9 goats); and the combination of double dose eprinomectin and albendazole (n = 12 goats). Strongyle nematode species were identified through nemabiome analysis targeting the ITS-2 region of copro-DNA. Species-adjusted egg counts were calculated to determine species-specific egg count reduction (ECR). The FECRT results confirmed multi-anthelmintic resistance; however, species-specific ECR indicated varying susceptibility among species. Haemonchus contortus and Trichostrongylus colubriformis were the main contributors to the resistance, whereas Trichostrongylus axei and Oesophagostomum columbianum remained highly susceptible to eprinomectin and albendazole. These findings demonstrate the value of integrating FECRT with nemabiome to provide species-level insights into treatment responses, supporting the development of targeted deworming protocols and improving anthelmintic resistance surveillance in regions with limited treatment options.