Searching for ivermectin resistance in a Strongylidae population of horses stabled in Poland

BACKGROUND: There are no available studies describing the possible resistance of strongyles to ivermectin in horses in Poland. One hundred seventy three horses from nine stud farms from South-Western Poland were studied. The effectiveness of ivermectin was studied on the 14th day after ivermectin administration using the fecal egg count reduction test, and a long-term observation of the egg reappearance period was carried out. The fecal study was carried out using a modified McMaster method, which typically detects 20 eggs per gram of stool. The results were subjected to statistical analysis that enabled quantification of the eggs in the stool samples. RESULTS: The study revealed high efficacy of ivermectin on the 14th day after administration without a shortening of the egg reappearance period. CONCLUSION: The results indicate that strongyles resistance to ivermectin in Poland is not a serious problem.