Prevalence of Eimeria bovis and Eimeria zuernii in German cattle herds and factors influencing oocyst excretion.

The present study was designed to investigate the prevalence of the pathogenic coccidia species Eimeria bovis and Eimeria zuernii in shed-reared animals in German dairy and fattening facilities. Samples were obtained from 65 cattle farms distributed randomly across all the regions of Germany regardless of the occurrence of clinical problems. The samples were obtained rectally. Faecal consistency and the total number of oocysts per gram of faeces (OPG) were determined, along with the OPG values for E. bovis and E. zuernii. A questionnaire was completed for each farm to record information about herd size and management, along with individual animal data. Eimeria oocysts were detected in 62 of these farms, which give a prevalence of 95.4%. The farm prevalence of the pathogenic species was 76.9% for E. bovis and 83.1% for E. zuernii. The number of oocysts excreted could not be correlated significantly with farm type or farm management but depended on the floor type, the age of the calves and the time after rehousing. Furthermore, there was a positive correlation between OPG and the observation of diarrhoea. E. zuernii had a greater influence on the occurrence of diarrhoea than E. bovis. This study confirms that herd management frequently does not meet the requirements of effective coccidia control despite the fact that the pathogenic coccidia E. bovis and E. zuernii are ubiquitous in German cattle populations.