Wystepowanie larw gza konskiego, Gasterophilus spp. u koni w gospodarstwach indywidualnych

The digestive tracts of 46 adult horses and four foals from private farms were examinated. The occurance of 1 species of botfly larvae, Gasterophilus intestinalis, found in the stomach of adults and foals, was confirmed. The study showed the prevalence of this parasite species in working horses of all ages in Poland (40%) with a mean intensity of 52 larvae per horse. Mainly the third instar was found (in 32% of examined animals); the second instar was less prevalent (8%). The results revealed that anthelmintic treatment in foals and young horses should include broad spectrum anthelmintics to control intestinal nematodes and botflies.