Control and anthelmintic resistance of horse strongyles in „X“ farm

Strongiloidosis is one of the most important endoparasite diseases in horses, caused by nematodes of Strongylidae geminate. For decades, the control and prevention of horse strongyles was based on frequent use of anthelmintics, which paved the path for development of specific resistant to antiparasitic agents nematodes, rooting one of the biggest concerns in veterinary field. The objective of the study was to determine the effectiveness of the treatment of horse strongyloidosis with ivermectin and fenbendazole and evaluate resistance to these anthelmintic substances in “X” stud farm. The study consisted of 5 parts. Firstly, 58 fresh stool samples were examined using modified MacMaster technique for quantative count of helminth eggs per gram (EPG) of facal matter. Secondly, the results were evaluated according to age, gender and breed of the selected horses, that reached the criteria - EPG ≥200 (n=52). Afterwards, the animals were randomly divided into two experimental groups: 1st Group and 2nd Group, and were treated with different anthelmintic agents. Ivermectin was used for Group 1 (n=20), and fenbendazole for Group 2 (n=20). In addition, from both groups control subgroups were formulated, which were not treated in any way, that could influence infection of parasites. After two weeks of treatment (14 days), EPGs were estimated repeatadly, evaluating antiparasitic treatment, the FECRT (fecal egg count reduction test) method was applied. After uncomplete and partly ineffective anthelmintic treatment with fenbendazole, L3 larvae had been cultivated for differentiation of the resistant strains. Strongyle eggs were discovered in all feacal samples (n=58) and 52 horses, based on methodological criteria, were used in further study. It has shown, that young horses (≤ 4 years) had 15,2% higher EPG compared to older horses (≥5 years) (p≤0,05). There was no statistically significant difference in EPG‘s to horse sex or breed (p≥0,05). Given the results of the study, treatment of strongyloidosis with Ivermectin was highly effective (FECRT 100%) and there was no indication of anthelmintic resistance (p<0,001). However, fenbendazole has shown lower efficacy and notable anthelmintic resistance to horse small strongyles was defined (FECRT 79%, p