Counting oocysts in coccidiosis cases
Elanco Animal Health has issued a reminder to vets about the importance of oocyst counts when diagnosing coccidiosis as the lambing season comes to an end.
Coccidiosis is a condition that causes diarrhoea in lambs that will also fail to thrive. Animal health specialists reiterate that it is important to count the presence of oocysts in lamb faeces in order to diagnosis coccidiosis reliably, as well as considering disease and farm history.
Lambs with oocyst counts of above 20,000 per gram is typical of coccidiosis-suffering sheep, however, up to 100,000 oocysts per gram have been reported in otherwise seemingly healthy lambs.
Elanco adds that the disease may also be present in sheep with lower oocyst counts and, therefore, it is important to be aware of the discrepancies of counting oocysts, which may lead to misdiagnosis.
The company also encourages identifying Eimeria species of oocysts if possible. There are 14 Eimeria species in sheep, which are each distinguishable by eye.
Coccidiosis tends to affect groups of lambs aged between three and eight weeks old. The disease may be triggered by a number or combination of stress-related factors, such as castration, weaning, turnout and bad weather.
"Vets should also not forget the importance of good management when advising farmers about coccidiosis control," says Elanco. "Lambing pen and high traffic area hygiene and age batching lambs are essential for long term control."
The Veterinary Medicines Directorate (VMD) is inviting applications from veterinary students to attend a one-week extramural studies (EMS) placement in July 2026.
