Calf diarrhoea is a major cause of losses, both physically and financially in young calves, with virally-caused issues in particular a major worry.

In this article, the National Animal Diseases Information Service (NADIS) highlights the issue and what can be done to prevent, or control, viral diarrhoea.

Causes:

Viruses are the commonest cause of calf scour, including:

Rotavirus

Coronavirus

The economic implications can be severe:

High cost of treatments – oral fluids for 3-5 days

Extra labour costs

High morbidity

Potential for high mortality

Protracted convalescence with poor weight gain

Clinical signs:

Eight to 14 days old

Acute onset watery yellow/green diarrhoea

Some calves deteriorate rapidly

Reluctance to stand and suck

Dull and increased salivation

Calf becomes dehydrated with sunken eyes and tight and inelastic skin

Recumbency

Death if not correctly treated.

1, Many calves with mild diarrhoea recover without treatment

2, Some calves deteriorate rapidly and require veterinary attention

3, Severely affected calves become weak and dehydrated with sunken eyes

4, Veterinary intravenous fluid therapy on farm (see below)

5, Same calf as above eight hours after treatment commenced

6, Adequate passive antibody transfer

7, High husbandry standards are essential

8, In spring, turnout to pasture as soon as weather permits

9, However, adverse spring weather can precipitate disease due to overcrowding and build up of infection in sheltered areas

Differential diagnoses:

Your veterinary surgeon may also consider

Enterotoxigenic e-coli, which is the most common cause of scours in 1-4 day-old calves

Salmonellosis

Cryptosporidiosis (zoonotic – transmissible to humans)

Diagnosis:

Rotavirus and coronavirus can be identified on laboratory examination

Treatments:

Diarrhoeic calf should be isolated in a dry, well-bedded pe.

1-2 litres of oral electrolyte are given four to eight times daily

Fluid offered by teat.

Use of oesophageal feeders if necessary

Intravenous fluids are essential in dehydrated calves that are unable to stand unaided

Oral antibiotics are generally not effective or necessary to treat viral infections

During recovery, alternate milk and electrolyte solution every four hours

Prevention and control:

Dam vaccination administered four to 12 weeks prior to calving protects her unborn calf against rotavirus and coronavirus

It takes 10-14 days for sufficient protective antibody levels to build up in the colostrum following vaccination

Adequate passive antibody transfer

A 40kg calf would require 4 litres of colostrum within the first 6-12 hours

Environmental hygiene

Dam nutrition

Mastitis prevention

Only 10-15% of beef cows are vaccinated, so there is scope for improvement