Expulsion of small strongyle nematodes (cyathostomin spp) following deworming of horses on a stud farm in Sweden

This study was conducted on a stud farm in Sweden to investigate the species composition of cyathostomins expelled in the faeces of horses after deworming using three different anthelmintic preparations. Twenty-seven horses excreting ≥200 strongyle eggs per gram faeces (EPG) were divided into three comparable groups and dewormed on day 0 with either of following compounds: 0.2mg ivermectin per kg body weight (bw), 19mg pyrantel pamoate per kg bw or 7.5mg fenbendazole per kg bw. For each of the 3 days following anthelmintic treatment faeces was collected from individual horses and subsamples were fixed in formalin. Four days after the anthelmintic treatment all horses were re-treated with ivermectin and faeces was collected on day 5. Individual subsamples from each of the four sampling occasions were examined for cyathostomin nematodes. Sixty-three to 270 worms per horse were identified to the species level.