Helminth intensity and diversity in organic meat sheep farms in centre of France

A helminthological study was undertaken at five sheep meat organic farms in the centre of France. The data obtained were compared with two extensive (contemporary of present study) or semi-intensive (literature data) conventional sheep meat farms. The nematode fauna of the region could be characterised by the presence of Trichostrongylus axei alongside with the dominant species recorded in other areas (Teladorsagia circumcincta and Trichostrongylus colubriformis with few Haemonchus contortus). The average intensity of infection was slightly less than 7000 worms in the digestive-tract; infection was on average higher in organic farms, although one organic farm had very low infection. This high intensity could be due to the lower frequency of anthelmintic treatments in these farms. Species/genera diversity was much higher in organic farms. Diversity was positively correlated to the area of pastures available and to the reduction of the number of treatment of ewes. (C) 2002 Elsevier Science B.V. All rights reserved.