An epidemiological study of gastrointestinal parasitism in dairy sheep flocks in Leon (NW Spain).

摘要

A study was carried out of the epidemiology of gastrointestinal nematode infections in milking ewes raised under semi-intensive management conditions in Leon province (North West Spain). A total of 779 faecal samples from 368 dairy sheep flocks of Churra and Churra X Assaf breeds were analysed during April 1991-March 1993. Each faecal sample was processed from a pool of about 8% of the ewes taken randomly in each of the farms. The flocks came from 6 areas in the south-east of Leon province. 685 (87.9%) of the faecal samples were positive, with a mean egg count of 134.3 epg (range 0 to 2050). No significant differences were found between different areas regarding the prevalence of infected flocks. Data showed that faecal egg output occurred all year around but there were 2 peaks. The first and most significant peak appeared during late winter to early spring (February/March) and the 2nd in mid summer (August). A relationship was found between climatic conditions and the pattern of faecal egg output. Comparison of the prevalence of infection between seasons showed a significant variation (chi-square=7.93; P=0.047).