Abstract
Two hundred and thirty-three lambs, naturally infected with Eimeria species, were used to access the effect of four different production systems on the output of Eimeria oocysts and daily weight gain. Ten Eimeria species were identified, E. ovinoidalis being the most prevalent species in all systems, followed by E. crandallis/weybridgensis. Multiple infections were common with up to nine Eimeria species recovered from individual specimens. No clinical signs of coccidiosis were observed in any of the groups. The output of oocysts was significantly different under the various conditions of husbandry. It was higher in the extensively managed group where no concentrates were given to the animals. Significant differences were also found between the groups for bodyweight development and daily weight gain, respectively. The mean fattening period was significantly shorter in the intensively managed groups compared with the extensively managed one. Estimated correlations between bodyweights at different ages and oocyst counts were significantly negative. The values ranged between -0.11 and -0.25. This relationship proves the economic impact of Eimeria infections in lambs. (C) 2004 Elsevier B.V. All rights reserved.