Infection with Eimeria sp. was studied in 135 lambs born to 79 ewes in four early lambing housed locks. In three of these flocks two different coccidiostats (monensin and decoquinate) were administered if the feed. Cohort lambs were examined clinically and a rectal faeces sample taken once a week. Samples with more the 300 oocysts per gram were speciated by morphology. Nine species were identified and Eimeria crandallis was the most prevalent. One of the flocks developed clinical coccidiosis before the introduction of coccidiostats. On the remaining farms no differences in the oocyst excretion rate of infected lambs were found between medicated and non-medicated lambs until Visit 6 nor in the proportion of lambs infected until Visit 8. It is suggested that coccidiosis may be controlled without coccidiostats, by identification of the risk factors associated with disease. Morphological variation of species and collection of large enough faeces samples from young lambs constitute limiting components for further epidemiological studies of coccidiosis.
Bibliographical noteFunding Information:
The authors would like to thank Janet Catchpole, Chris Norton and Jackie Green from the Central Veterinary Laboratory, Weybridge, for the technical assistance and advice provided throughout the study, and the Basque Government and Melrose Trust for their financial support. L.E. Green was in receipt of a Wellcome Trust Veterinary Research Training Scholarship.
- Eimeria sp.
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