Internal parasites of horses on mixed grassveld and bushveld in Transvaal, Republic of South Africa.

Between 1980 and 1982, the gastrointestinal tracts of 17 horses which had been grazing on mixed grassveld at Potchefstroom and bushveld at Onderstepoort in the province of Transvaal, Republic of South Africa, were examined at necropsy and processed for parasite recovery. The large strongyles and their prevalences were as follows: Strongylus vulgaris and associated lesions (88-94%), Strongylus edentatus (24%), Strongylus equinus (30%), Triodontophorus nipponicus (35%) and Craterostomum acuticaudatum (18%). The seven most prevalent and abundant cyathostomes collected were Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicostephanus calicatus, Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus minutus and Cyathostomum coronatum. Gasterophilus intestinalis was the most prevalent and abundant botfly larva recovered. Most of the cyathostome larvae and adults were present during all seasons except winter. The distribution of cyathostome species in the large intestine of the host is discussed.