WA Livestock Disease Outlook - for producers

Ill-thrift in Merino ewe weaners

  • Ill-thrift, weakness, diarrhoea and deaths were seen in 4–6-month-old Merino weaners in the Wheatbelt.
  • In total, 30 weaners died and 70 weaners were affected from a mob of 700.
  • The weaners were grazing canola stubble with ad lib lupins via feeders and were supplemented with hay.
  • The weaners were vaccinated for pulpy kidney as lambs and received a booster when losses began.
  • Blood samples, small intestinal swabs, fresh and fixed tissue samples and rumen content were all submitted for laboratory examination.
  • Testing for annual ryegrass toxicity of rumen content and enterotoxaemia was negative, and intestinal worm egg counts and Salmonella cultures were negative.
  • Following laboratory testing and bacterial culture, infection with Vibrio cholerae was diagnosed. The serogroup detected was not one associated with severe human cholera outbreaks.
  • V. cholerae is an unusual finding in gastroenteritis cases in sheep in samples tested at AHL.