A DESCRIPTIVE EPIDEMIOLOGIC-STUDY OF COCCIDIOSIS IN EARLY LAMBING HOUSED FLOCKS

Infection with Eimeria sp. was studied in 135 lambs born to 79 ewes in four early lambing housed flocks. In three of these flocks two differ ent coccidiostats (monensin and decoquinate) were administered in the feed. Cohort lambs were examined clinically and a rectal faeces sample taken once a week. Samples with more than 300 oocysts per gram were s peciated by morphology. Nine species were identified and Eimeria crand allis was the most prevalent. One of the flocks developed clinical coc cidiosis before the introduction of coccidiostats. On the remaining fa rms 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 c occidiosis may be controlled without coccidiostats, by identification of the risk factors associated with disease. Morphological variation o f species and collection of large enough faeces samples from young lam bs constitute limiting components for further epidemiological studies of coccidiosis.