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Sawfly poisoning in sheep and goats
S M Thamsborg1, R J Jørgensen, E Brummerstedt
1Department of Internal Medicine, Royal Veterinary and Agricultural University, Copenhagen, Denmark.
The Veterinary Record
|September 12, 1987
Summary
Sheep experienced severe illness, including depression and death, due to ingesting blue-black birch sawfly larvae. Post-mortem exams confirmed liver necrosis and kidney damage, identifying Arge pullata larvae as the cause.
Area of Science:
- Veterinary Pathology
- Toxicology
- Entomology
Background:
- Sheep flocks can be susceptible to various health issues affecting livestock.
- Accidental ingestion of insects or their larvae can lead to toxicosis in grazing animals.
Purpose of the Study:
- To investigate the cause of a sudden, fatal illness in a flock of sheep.
- To identify the etiological agent responsible for the observed clinical signs and post-mortem findings.
Main Methods:
- Clinical observation of affected sheep and post-mortem examination of deceased animals.
- Identification and quantification of ingesta, including insect larvae, in the gastrointestinal tract.
- Laboratory and field studies to confirm the toxicity of the suspected agent.
Main Results:
- Sheep exhibited depression, anorexia, incoordination, and difficulty rising, with a mortality rate of 20% (50 out of 250).
- Necropsy revealed petechial hemorrhaging, acute liver necrosis, and renal tubular degeneration.
- Larvae of the blue-black birch sawfly (Arge pullata) were found in significant numbers within the rumen and gut.
Conclusions:
- The blue-black birch sawfly (Arge pullata) larvae were identified as the causative agent of the toxicosis in sheep.
- Ingestion of Arge pullata larvae can lead to severe gastrointestinal, hepatic, and renal pathology in sheep.
- This case highlights the potential for insect larvae to cause significant livestock losses.