EN
Ruminants often live in environments where the natural balance has been disturbed by humans. As a result, there is a transfer of parasitosis to domestic animals and sometimes humans. The aim of the study was to determine the annual species composition and level of gastrointestinal nematode infection of mouflon (Ovis aries musimon) from the half-open breeding colonizing areas of the Goleniowska Forest, and to assess the effectiveness of deworming. The course of the parasitic infection of mouflon depends largely on geoclimatic and breeding factors. These diseases are caused by more than 17 species of nematodes with varying degrees of pathogenicity. Due to the high degree of parasitic infections in deer, both in Poland and abroad, it is necessary to develop specific preventive programs using preparations with a broad spectrum of action.