Sudden death in Merino ewes
- Cases of sudden death were investigated in four-year-old Merino ewes in the Wheatbelt.
- In a mob of 800 ewes, 13 were found dead in one corner of the paddock. All animals were approximately two months pregnant and had a poor vaccination history.
- The mob was fed barley and lupins after a cold front/rain event, and deaths occurred the next day.
- A post-mortem was performed on one animal but there was no obvious cause of death. The rumen (first stomach) contained barley and lupins.
- Samples were taken and laboratory testing revealed kidney damage and irritation to the lining of the rumen. Damage to the kidneys and tissues of the rumen was found to be caused by a build-up of oxalate crystal deposits.
- The most common cause of oxalate poisoning is through access to oxalate-containing plants such as weed plants in stubble paddocks. The plant species to which these animals may have been exposed are being investigated.
- Oxalate poisoning commonly occurs following summer rain when sheep consume alternative feed sources when pasture feed is wet.