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United Kingdom
Cow laying in field

Neonatal Scour

Newborn calves are extremely susceptible to calf scours especially during their first 28 days of life.

Bacteria and viruses, by attacking the lining of the calf's intestine, cause diarrhoea. It reduces the absorption of essential nutrients from milk and leads to dehydration.

If disease is severe, the calf may die; however, even the calves which survive severe disease will have longer term poorer performance than healthy calves.

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  • Rotavirus, coronavirus, primary bacteria (K99 E. coli; Clostridium perfringens Type C, Salmonella spp.) and parasites (cryptosporidia, coccidia) are the most common causes of diarrhoea.











    E.coli K99


    Salmonella spp.


    No diagnosis


    Table 1 Prevalence of calf scour from MILK DEVELOPMENT COUNCIL1




    % samples positive

    Cryptosporidium spp






    E. coli K99


    Table 2 Prevalence of calf scour2


    Controlling rotavirus, coronavirus and E. coli can thus significantly reduce losses due to calf scour even if you have other problems on farm.



    Contributing factors can allow the emergence of the disease:

    • Insufficient colostrum within the first 6 hours of life.
    • Poor quantity colostrum
    • Over-consumption of milk, creating an environment in which certain bacteria thrive, causing “milk” scours
    • Difficult calving
    • Poor hygiene in calving pens and rearing pens.
    • Cold, wet weather
    • Over stocking
  • Depending on the cause, calf scours can strike anytime from the first few hours after birth up to a month of age. Heifers and second calver dairy cows often produce lower quality and a lower quantity of colostrum and thus their calves may be more likely to scour.

    • Diarrhoea, sometimes containing blood or mucus, which can lead to death in 12-48 hours
    • Dehydration
    • Weight loss
    • Weakness
    • reduced growth
  • Diagnosis may be made on clinical signs and epidemiology, but additional tests are needed (faeces samples, post-mortem examinations & blood samples to assess adequacy of colostrum intake) to be definite regarding the cause of an outbreak of neonatal scour in calves.

  • Successful treatment of calf scours depends on rapidly rehydrating scouring calves.

    • Oral rehydration products help restore lost electrolytes and essential nutrients, however in severely dehydrated animals intravenous fluids are necessary.
    • In bacterial scours cases, antibiotic therapy may be advised for, via oral or parenteral route.
    • Cryptosporidia can be treated with an oral medication containing halofuginone lactate.
    • Make sure calves start sucking as soon as possible after calving, to get adequate colostrum (10% of the body weight in the first 6 hours of life). In dairy herds it is thought to be better to separate the cow and calf as soon as the calf is dry and milk colostrum from the cow to ensure the calf gets enough within the first hours of life.
    • Vaccinate the cow prior to calving to provide increased immunity through the colostrum against Rotavirus, Coronavirus and E. coli if these infectious agents are implicated in the disease outbreak on a particular farm.
    • Reduce the exposure of newborn calves to infectious agents
      • Separate healthy calves from sick calves immediately;
      • Be sure equipment, boots and hands are thoroughly cleaned after handling sick animals.
      • Clean out calving pens regularly and calf pens between batches.
      • Batch calving and batch rearing to minimize spread of infection from older to younger animals.
      • If calving cows outdoors- as calving season progresses remove cows still not calved to a fresh paddock rather than continuing to remove cows and calves leaving later calving cows to give birth in an increasingly contaminated environment.
    • Reduce stress on cows and calves- provide shelter in bad weather for young calves outdoors. Cows should be in Body Condition Score 3 or 3.5 for optimum calving.
      • Assist with calving as necessary, especially with heifers;
      • Keep animals as clean and dry as possible.
  • What are the most common causes of calf scour?
    In most surveys Rotavirus and Cryptosporidia are the most common causes followed by coronavirus and enterotoxigenic E.coli. Salmonellosis may also be involved in some cases. In a NADIS survey the most common organisms causing scours are rotavirus (29%), cryptosporidia (20%),coccidia (11 %), coronavirus (6%), E. coli K99 (4%), and Salmonella species (3%).3

    Should scouring calves be fed milk?
    Historically scouring calves were taken off milk and put on oral fluids until they recovered. This is fine for “milk scours” caused by overflow of undigested milk into the lower intestine that respond quickly to oral antibiotics and reduced milk feeding. However given that the common causes of neonatal diarrhoea in calves in U are rotavirus and cryptosporidia and with these agents it can take a few days for animals to stop scouring, many farmers now treat scouring calves with electrolytes and leave them on reduced levels of milk or with suckler cows leave the calves with their dam.

    Why are calves born to heifers more vulnerable to scour?
    Generally heifers produce poorer quality colostrum than cows. Hence it is better to calf heifers at the start of the calving season when facilities are clean.

  • MILK DEVELOPMENT COUNCIL Calf Enteritis & Septicaemia Project No. 96/R5/101

    NORTHERN IRELAND DISEASE SURVEILLANCE REPORT Prevalence of calf scour ref Veterinary Record March 13, 2010 page 3182

    DairyCo Calf scour3