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Vetdle Archive

Archive Case #68: Ovine Coccidiosis

Sheep veterinary case - Medium - May 10, 2026

Clinical Clues

  1. Recently weaned lambs are developing dark diarrhoea and falling behind in growth.
  2. The farmer reports that a few are straining and dirty around the tail.
  3. Affected lambs are dull but remain on their feet.
  4. The problem has appeared after crowding in a high-contamination environment.
  5. Faecal testing shows heavy protozoal oocyst shedding in the lamb group.
  6. Ovine coccidiosis commonly causes post-weaning diarrhoea, tenesmus, and poor thrift in young lambs.

Diagnosis

Ovine Coccidiosis

This case is most consistent with Ovine Coccidiosis because the lambs developed diarrhoea and ill thrift after weaning under conditions that favour coccidial build-up. The most important clues are the age group, straining, and faecal results, which make a primary nematode problem less likely.

Learning review

Review the case evidence

Use the paired clues to explain how the evidence in this sheep case supports the provided diagnosis, Ovine Coccidiosis, then compare your reasoning with the case explanation.

Evidence checkpoints

Clues 1-2

  1. Clue 1: Recently weaned lambs are developing dark diarrhoea and falling behind in growth.
  2. Clue 2: The farmer reports that a few are straining and dirty around the tail.

Clues 3-4

  1. Clue 3: Affected lambs are dull but remain on their feet.
  2. Clue 4: The problem has appeared after crowding in a high-contamination environment.

Clues 5-6

  1. Clue 5: Faecal testing shows heavy protozoal oocyst shedding in the lamb group.
  2. Clue 6: Ovine coccidiosis commonly causes post-weaning diarrhoea, tenesmus, and poor thrift in young lambs.

Self-review prompts

  1. After clues 1-2, what evidence from this sheep case shaped your initial interpretation?
  2. When you compare clues 3-4 with clues 1-2, what changed in your reasoning about Ovine Coccidiosis?
  3. How do clues 5-6 align with the case explanation for Ovine Coccidiosis?

Educational Use

Vetdle archive cases are educational veterinary games for diagnostic reasoning practice. They do not provide veterinary advice, diagnosis, treatment, or professional medical guidance.