The distribution and abundance of parasitic infections in sheep grazing on irrigated or on non-irrigated pastures in North-Eastern Spain.

The parasitic output in faeces was studied in five sheep farms of Zaragoza area (Spain) during three years. Two of them utilized irrigated pastures. The latter were characterized by a high prevalence of Dicrocoelium lanceolatum, Fasciola hepatica and Protostrongylids. Flood-irrigation did not interfere with digestive-tract strongyles and did not favour Moniezia sp. infection. The heterogeneity of the parasitic output was more intense on irrigated pastures.