E.coli Diarrhoea

According to HAF RESEARCH data most common cause of diarrhoea in calves continues to be E.coli .

What is E.coli?

E.coli is a bacterium that is present in the guts of normal animals. Most types of E.coli do not cause disease, however three types of E.coli are associated with diarrhoea in calves.

One type (known as ETEC) attach to and damage the small intestine and produce a special type of toxin (known as an enterotoxin), the second (EPEC) attaches to and damages the small intestine but do not produce enterotoxins, and the third (EHEC) attaches to and damages the large intestine

Clinical Signs

Young calves (usually <3 days old)
Calves become depressed, don’t drink, dehydrate and die rapidly Diarrhoea is very watery


Older calves (usually <21days)
Usually not so rapid or as severe as ETEC
Diarrhoea yellow and watery


Older calves (around 14 days)
Often bloody diarrhoea



  • Age of calf
  • Severity and nature of diarrhoea
  • Laboratory tests can identify the protein used by bacteria to attach to the gut


  • Difficult to diagnose as signs are very similar to diarrhoea caused by other organisms, and non-disease causing E.coli are present in most faecal samples
  • Examination of material from post-mortems can confirm E.coli –related disease


  • Replacing lost fluids is the most important part of treatment. This can range from oral electrolytes for moderately affected calves to intravenous fluids for severely affected calves.
  • Commercial electrolytes are more expensive than the home-made version but in moderate to severe cases they are much more effective
  • Antibiotics can help in some cases, but they should be used with caution and if possible sensitivity testing should be undertaken.


  1. Keep the environment as clean as possible, this refers to the calving yards as well as the calf pens.
  2. Single penning of young calves will significantly reduce the spread of diarrhoea
  3. Sick calves will pass a vast number of disease-causing bacteria. Disinfection is vital
  4. If possible use an all-in-all-out system. This allows pens to be disinfected between batches and prevents disease being passed on to every new calf that enters the building.
  5. Ensure good colostrum intake. In herds with problems, feeding bulked colostrum for at least 7 days can significantly reduce the number of cases of scour

For ETEC diarrhoea only, vaccination is available. This is given to the mother in late pregnancy. The colostrum then contains antibodies that help prevent ETEC infection. For the best effect colostrum feeding should continue for at least a week


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