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Viruses and bacteria are major causes of infectious calf scours. The single biggest cause is rotavirus, but other viruses (such as coronavirus), cryptosporidia (a protozoan organism) and the bacteria E.coli K99 also cause problems. A number of these pathogens – particularly rotavirus and cryptosporidia – are present on most farms and often all they require is a trigger factor (eg. stress) to cause disease.

Scour prevalence on UK farms

70% of farmers have seen scour in calves under six months of age during the previous 12 months and more than 40% of producers have lost animals to the disease over the same period1.

Cost of scours

Calf scours cost money. ADAS estimates the cost of a scour outbreak in a 100-cow suckler herd (assuming 90 calves born) to be £57942.

The effects of scour

Some viral causes of scour – such as rotavirus and coronavirus – destroy the gut lining of the small intestine, reducing the digestive and absorptive capacity of the intestine and causing diarrhoea. Other infectious causes – such as E.coli – produce toxins, which can lead rapidly to fatal disease. Even if calves recover from these infections they may never perform as well as non-affected animals.
Viruses like rotavirus and coronavirus cannot be cured with antibiotics – so prevention, through vaccination, is the only effective way of controlling these scours.

Disease management

Calves are most at risk from infectious scour in the first 3-4 weeks of life and need a source of continuous protection – through passive transfer of antibodies in the colostrum – to keep them healthy. On many units, normal colostrum does not provide enough antibodies. However, single shot vaccination of the calf's mother between 12 and 3 weeks before calving boosts colostrum quality, allowing high levels of antibodies against rotavirus, coronavirus and E.coli K99 to be fed in early life.

1. ADAS Report: Economic impact of health and welfare issues in beef cattle and sheep in England (p. 35/36).
2. MSD Animal Health survey. November 2014.

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