Stan i dynamika zarażenia owiec pasożytami przewodu pokarmowego w okresie letnim w różnych systemach chowu

The aim of the study was to determine the level of gastro-intestinal parasite infections in sheep farmed organically (herd E, 30 ewes) and kept conventionally (in two conventional sheep operations), in total confinement (herd K1, 16 ewes) or under a pasture system (herd K2, 25 ewes). Every month during the grazing season coproscopic examinations by the McMaster method were conducted, making a total of 455 fecal samples analyzed, and at the end of the season diagnostic sections of the entire gastro-intestinal tracts from 18 sheep (6 ewes from each of the sampled flocks) were performed. The intensity of infection with coccidia, and especially with pathogenic species of gastrointestinal nematodes (i.e. Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus vitrinus) was much higher in sheep from the organic farm, compared to two farms conventionally managed. Meanwhile, in the conventional farm with grazing animals (herd K2) Nematodirus battus – a highly pathogenic, foreign species of nematode was found – and the herd was also largely infected with the tapeworms of Moniezia genus. A higher level of helminth infections and especially much greater species diversity of gastrointestinal nematodes observed in grazing sheep indicate a substantial role of pasture in the formation of parasitic clusters. In pasture management, alongside the biology and pathogenesis of parasites the use of proper preventive measures is most important.