Analysis of the Major Gastrointestinal Parasites Community in Yili Horses in Zhaosu of Xinjiang, Western China

This investigation shows that is possible to determine fecundity and species composition of the gastrointestinal community in Yili horses and analyse the possible relationships with intestinal parasites using sex, age, and management strategy. A total of 118 of the 124 sampled horses were infested with oxyurids, ascaridids, Spiruridae, Anoplocephalidae, Gasterophilus, large strongyles (strongylids), and small strongyles (cyathostomins: cyathostomes). Adults and/or larvae from two strongylid and 11 cyathostomin species were identified, with the following proportions of oveall parasite abundance (as eggs per gram of faeces; EPG) in Yili horses: Strongylus equinus 82.26%, Strongylus edentatus 23.39%, Cyathostomum coronatum 34.68%, Cyathostomum subcoronatum 18.55%, Cylicostephanus longibursatus 56.45%, Cylicostephanus calicatus 75.81%, Cylicocyclus radiatum 3.23%, Cylicocyclus nassatus 72.58%, Cylicocyclus ultrajectinus 3.23%, Cylicocyclus elongatum 6.45%, Cylicodontophorus bicoronatum 8.87%, Cylicodontophorus euproctus 13.71%, Cylicodontophorus pateratum 23.39%. Significant differences in the prevalence of separate strongylid species or their proportions in the community were not observed between females and males or between age groups (p > 0.05). Young horses (< 3 years old) had more severe infections of P. equorum and Oxyuris equi. Free-ranging horses were more infected with S. equinus, O. equi, T. equi, and G. intestinalis than horses under other management strategies. The optimum treatment interval may vary depending on a range of factors, including the type of pasture, grazing practices, stocking density, time of the year, and climatic conditions. An EPG > 200 is the main deworming objective.