Occurrence of Internal Parasites and Anthelmintic Resistance in Goats

Extensive anthelmintic (AH) use for endoparasitism prevention, especially gastrointestinal strongyle (GIS) infections, led to AH resistance (AR). This study assessed the internal parasitic profile and AR occurrence in goat herds. Five herds (H, n = 300) raised in household systems in Romania (2020-2021) were dewormed with eprinomectin in the fall (H1, H2) and albendazole in the spring (H3-H5). Fecal samples (n = 67) were collected pre- and 14 days post-AH administration. Coprological examinations, coprocultures, and polymerase chain reaction (PCR) were performed. Anthelmintic resistance was detected in H1, H2, and H5. Pre-AH administrations, Eimeria spp. was the most common parasite (95.5%), followed by GIS (91.0%), P. rufescens/M. capillaris (77.6%), Dyctiocaulus filaria (56.7%), and Moniezia spp. (43.3%). Teladorsagia circumcincta (4/5), Trichostrongylus colubriformis (4/5), Oesophagostomum venulosum (3/5), Haemonchus placei (3/5), Haemonchus contortus (2/5), and Cooperia oncophora (2/5) were identified by PCR. Mean OPG/EPG values for Eimeria spp. and GIS were <1000 eggs/gram feces, tending to be higher in young versus adult goats and in autumn versus spring. FECR (90%CI) values post-AH administration were 38.42 (23.4; 71.8), 54.71 (-4.1; 75.1) for eprinomectin, and 9.78 (-1.7; 64.8) for albendazole, suggesting AH ineffectiveness and AR presence in H1, H2, and H5, respectively. These findings highlight that specific management measures are needed.