Calf scour (diarrhoea) is a common problem encountered and there are several potential causes - bacterial, viral, protozoal and nutritional. The age of the calf affected by scour is important in determining the most likely culprit.

Calf age
1-4 days; E-coli most likely
1-3 weeks; Rotavirus, Coronavirus, Cryptosporidia
2-6 weeks; Salmonella

E-coli scour seen in very young calves is quite uncommon but when it does occur is associated with high mortality rates. Calves suffering from meningitis or septicaemia, (infection in the blood) can look similar, close examination by a vet ± confirmation of the presence of e-coli in a faecal sample is important in determining the most likely cause and therefore the correct treatment. Calves affected by E.coli scour become dehydrated and require fluid support either by teat/stomach tube or in those very weak directly in to the vein. Antibiotics orally (eg Synulox calf boluses) are also required. Where an outbreak is occurring good hygiene is paramount with the isolation of affected calves and ensuring all newborns receive adequate colostrum within the first 24 hours. Vaccinating cows still to calve will also help to reduce the occurrence by providing protection via the colostrums, (see vaccination details later).

In calves aged 1-3 weeks by far the most common cause is rotavirus. Confirmation can be made by taking faecal samples from 4 or more affected animals as a small number of ‘normal’ calves can test positive for rotavirus without showing any signs of disease. Severely affected calves require fluids directly in to the vein, (which usually rapidly shows a marked improvement), followed by electrolyte solutions alternated with colostrums/milk by teat or stomach tube every couple of hours. Maintaining hydration is the key to saving affected calves and as the cause is viral not bacterial antibiotics are not indicated. Calves affected by the less common Coronavirus show similar sometimes milder signs and are treated the same. Cryptosporidia can cause scour on its own but often contributes to the severity of viral scours. Again no specific treatment is available and so affected calves need to be kept well hydrated.

Fortunately outbreaks of Salmonella are relatively rare as with some types of Salmonella the disease can be transmitted to humans. Faecal samples will confirm the diagnosis and in calves antibiotic treatment should be initiated, mortality rates can be high. Salmonella can also be a cause of abortion in cows and so a history of recent abortions as well as diarrhoea in cows/calves makes a diagnosis of Salmonella more likely.

General measures to control and prevent calf scour

1, Isolate affected calves from other calves and remove from groups of cows still to calve
2, Ensure all calves receive adequate good quality colostrums as soon after calving as possible
3, Remove newly calved from the group still to calve to prevent the build up of the infectious agents in the environment.
4, Compact calving period
5, Combined vaccine to give protection against rotavirus/coronavirus/E.coli all cows yet to calve can be vaccinated if more than 2 weeks prior to their due date as then the colostrums will contain antibodies against these pathogens so reducing the chances of disease occurring in calves that receive adequate colostrums or at least making the disease much less severe in any that are affected.

For more advice and an answer to any further questions you may have please contact one of the large animal vets here at Parkside.