Calf Diarrhoea

Moredun-logoSummary written by Colin Mason BVM&S, BSc, CertCHP, MRCVS; George Caldow BVM&S, MSc, Cert CHP, Dip ECBHM, MRCVS; and Frank Katzer BSc, DPhil

Taken from Moredun Foundation Newsheet Volume 5 No. 14 (2012)




  • Calf diarrhoea (scour) can cause significant losses in UK herds.
  • The major causes of infectious diarrhoea in calves are commonly found in herds whether or not calf diarrhoea is a problem.
  • There are numerous infectious and non infectious causes of diarrhoea and as the clinical signs are general, it is not possible to identify or predict a specific cause from the clinical signs alone
  • Although many infectious agents have the potential to cause diarrhoea in young calves there is good evidence at the moment for the common involvement of only 6 micro-organisms as significant causes.  These are:-
    • the viruses rotavirus and coronavirus
    • the bacteria enterotoxigenic E.coli (ETEC) and Salmonella (particularly types Dublin and Typhimurium)
    • the protozoan parasites Cryptosporidium and coccidia
  • Mixed infections with one or more of the above infectious agents are common.
  • The occurrence of disease is influenced by environmental and management factors. Therefore much can be done to control calf diarrhoea through management.
  • Diagnostic testing is only worthwhile if it is going to influence treatment, prevention and control strategies. Collect faeces samples (15g approx.) from at least three, and preferably six, untreated calves with diarrhea in the early stages of disease to be tested for all potential scour pathogens.
    • Infection with rotavirus, coronavirus, E. coli (ETEC), Salmonella, Cryptosporidium or coccidiais not in itself lethal to the calf.  What may kill the calf is the resulting dehydration and acidosis from the loss of fluid and salts in the diarrhoea, or in the case of salmonellosis bacterial invasion of the body through the damaged intestine. Long term intestinal damage may also result in failure to thrive.
  • Within a herd health plan there should be protocols for the early recognition and treatment of calf diarrhoea.
  • A risk assessment may be carried out for your herd to determine whether vaccination would be beneficial in the prevention of diarrhoea due to rotavirus, coronavirus or E. coli (ETEC).


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