EN
The purpose of the study was to evaluate intestinal parasite infections in riding horses from one stud farm and 5 riding clubs based on fecal egg counts, and in working horses on the basis of necropsy. The prevalence of strongyles was similar in stud farm and clubs (71.0% and 36.3%-87.1%, respectively), with higher egg counts in the farms (924) compared to the clubs (302-515). Larvae differentiation indicated a very low prevalence of large strongyles in the above horses. Parascaris equorum was not very prevalent in adult Arabian horses (0.5%), while 3.7-21% of horses in clubs were infected. Anoplocephala spp. was not very prevalent in Arab- -horse farms (6.7%) and in riding clubs (0-1.8%). 4 large strongyle, 14 small strongyle species and 5 other species of parasites were found in fourteen horses slaughtered for meat. The results indicated a high prevalence of large strongyles (S. vulgaris 64.3%, S. equinus 21.4%, and Triodontophorus spp. 14.3%-21.4%). The most prevalent cyathostome species were Coronocyclus coronatus (57.1%), Cylicocyclus nassatus (50.0%) and Cyathostomum catinatum (42.9%). Tapeworm and botfly infections were found in individual cases (7.1%). Horses in Arab farm and riding clubs were routinely de-wormed twice a year. It was noted that no anthelmintics had been used in the slaughtered horses. The results revealed that small strongyles (cyathostomes) are the most common intestinal parasites in horses despite regular anthelmintic treatment. In addition it seems important to take S. vulgaris infection into account when diagnosing abdominal pain, i.e. colic in un-wormed horses (working or kept in organic farming systems).