Recent livestock disease cases in WA
Eperythrozoonosis causes death in 30 lambs in the Great Southern
- Lambs still on their mothers presented with anaemia and sudden death.
- Marking had occurred one month prior and lambs received 6-in-1 and erysipelas vaccination, selenium and vitamin B12 supplementation and were drenched against worms. Marking equipment had been cleaned with a disinfectant.
- Carcasses were pale with watery blood, enlarged spleens and mesenteric lymph nodes and thickened small intestines. A blood smear and PCV showed a marked regenerative anaemia and large numbers of Mycoplasma ovis (eperythrozoonosis).
- M. ovis is transmitted via blood (e.g. contaminated needles or surgical instruments) or biting insects such as ticks, flies, fleas and mosquitoes. In conjunction with nutritional stress and a heavy worm burden, the disease in lambs can be severe.
- Worm egg counts were negative, consistent with recent drenching, however the histopathological changes were suggestive of prior intestinal damage caused by worms.
- Deaths in this flock resolved without treatment. Good nutrition, parasite control and reducing handling stress of affected animals can reduce losses until animals recover.
- Consider M. ovis if there is anaemia, jaundice and deaths especially after stressful events and in young animals. Outbreaks of the disease have previously been seen more frequently in spring.
- Key samples: blood smear, EDTA – take samples from affected and unaffected animals.
- Read more on our website on eperythrozoonosis.
Weakness and death in lambs in the Wheatbelt due to pulpy kidney (enterotoxaemia)
- Eight 6-8 week old lambs became weak and died after showing unusual behaviour. At marking 5 weeks prior lambs had received a 3-in-1 clostridial vaccine and the flock was fed on hay, lupins and oats.
- Ileal contents tested positive for enterotoxaemia toxin. This was supported by a finding of pulmonary oedema and accelerated autolysis of the proximal convoluted tubules of the kidney. There was a significant roundworm burden.
- Given the abnormal behaviour, blood was tested for lead toxicity (reportable), which was negative.Pulpy kidney can occur in unvaccinated or incorrectly vaccinated sheep, where there is a sudden change to high carbohydrate, low-fibre feed (such as lush pasture/grain) and is more likely in sheep that are rapidly growing. A one-off vaccination is generally not sufficient to provide immunity in previously unvaccinated sheep and lambs. Read more on pulpy kidney vaccination.
- Differential diagnosis: lead toxicity (reportable) and polioencephalomalacia (Vit B1 deficiency) where there is abnormal behaviour. Sudden deaths can occur with fluoroacetate plant poisoning and anthrax (reportable), which also presents with bleeding from orifices.
- Key samples: 10mL fresh, ileal content, EDTA blood, fresh and fixed tissues (brain, kidney, lung, liver).
In early spring, watch for these livestock diseases:
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Worms in sheep and cattle
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