Individual administration of three tanniferous forage plants to lambs artificially infected with Haemonchus contortus and Cooperia curticei Felix Heckendorn a,b, * , Dieter Adrian Ha ¨ring c , Veronika Maurer a , Markus Senn b , Hubertus Hertzberg a,d a Department of Veterinary Parasitology, Research Institute of Organic Agriculture, Ackerstrasse, CH-5070 Frick, Switzerland b Physiology and Animal Husbandry, Institute of Animal Sciences, ETH Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland c Research Station Agroscope Reckenholz—Tanikon ART, Reckenholzstrasse 191, CH-8046 Zurich, Switzerland d Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, CH-8057 Zurich, Switzerland Received 24 November 2006; received in revised form 15 January 2007; accepted 16 January 2007 Abstract We investigated direct anthelmintic effects associated with the feeding of fresh tanniferous forages against established populations of Haemonchus contortus and Cooperia curticei in lambs. Twenty-four parasite naive lambs were inoculated with a single dose of infective larvae of these two parasites 27 days prior to the start of the feeding experiment. Lambs were individually fed with either chicory (Cichorium intybus), birdsfoot trefoil (Lotus corniculatus), sainfoin (Onobrychis viciifolia) or a ryegrass/ lucerne mixture (control) for 17 days. Animals where then united to one flock and subjected to control feeding for another 11 days to test the sustainability of potentially lowered egg excretion generated by tanniferous forage feeding. When compared to the control, administration of all tanniferous forages was associated with significant reductions of total daily faecal egg output specific to H. contortus (chicory: 89%; birdsfoot trefoil: 63%; sainfoin: 63%; all tests P < 0.05) and a tendency of reduced H. contortus worm burden (chicory: 15%; birdsfoot trefoil: 49% and sainfoin: 35% reduction). Irrespective of the condensed tannin (CT) containing fodder, no anthelmintic effects were found against C. curticei. Cessation of CT-feeding followed by non-CT control feeding did not result in a re-emergence of faecal egg counts based on faecal dry matter (FECDM) in any group, suggesting that egg output reductions are sustainable. The moderate to high concentrations of CTs in birdsfoot trefoil (15.2 g CTs kg 1 dry matter (DM)) and sainfoin (26.1 g CTs kg 1 DM) were compatible with the hypothesis that the antiparasitic effect of these forages is caused by their content of CTs. For chicory (3 g CTs kg 1 DM), however, other secondary metabolites need to be considered. Overall, birdsfoot trefoil and in particular sainfoin seem promising candidates in contributing to an integrated control strategy against H. contortus not only by mitigating parasite related health disturbances of the host but also by a sustained reduction of pasture contamination. # 2007 Elsevier B.V. All rights reserved. Keywords: Chicory; Birdsfoot trefoil; Sainfoin; Haemonchus contortus; Cooperia curticei; Condensed tannins; Sheep 1. Introduction The wide spread development of anthelmintic resistant populations of gastro-intestinal nematodes (GIN) during the last decade (Jackson and Coop, 2000) and the requirements for reduced anthelmintic input in www.elsevier.com/locate/vetpar Veterinary Parasitology 146 (2007) 123–134 * Corresponding author at: Department of Veterinary Parasitology, Research Institute of Organic Agriculture, Ackerstrasse, CH-5070 Frick, Switzerland. Tel.: +41 62 865 72 93; fax: +41 62 865 72 73. E-mail address: Felix.Heckendorn@fibl.org (F. Heckendorn). 0304-4017/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.vetpar.2007.01.009