Diarrhoea in Farm animals

Question 1

3 factors involved

Answer 1

Pathogens
Calf Factors (immune system, stress)
Environment and Management

Question 2

calf diarrhoea - pathogens

Answer 2

E. coli 
rotavirus 
Coronavirus 
Cryptosporidium 
Salmonella 
mixed infections 
(Coccidiosis)

Question 3

rotavirus

Answer 3

Calves aged 1 – 3 weeks
High morbidity but low mortality
Duodenum and jejunum

Question 4

coronavirus

Answer 4

Slightly older calves
? Slightly higher mortality
Ileum, caecum and colon

Question 5

salmonella

Answer 5

Zoonosis- Public Health Issue
Culture of Salmonella is always significant 
Any age of animal 
Systemic illness and pyrexia 
Species important in identifying source

Question 6

coccidiosis

Answer 6

Slightly older weaned calves
May give blood stained faeces
May also be subclinical giving poor growth rate

Question 7

diagnosis

Answer 7

Pathogens may be present in the absence of clinical disease 
take faecal samples, not swabs 
Sample healthy and affected animals 
Send to competent laboratory 
Bacteriology only is not sufficient

Question 8

faecal appearance - calves

Answer 8

can be variable

notoriously unreliable

Question 9

growing animal/adolescent - causes

Answer 9

Endoparasites 
Rumen Acidosis 
Salmonella 
Nutritional 
Post Weaning Scours

Question 10

bovine viral diarrhoea virus (BVDV)

Answer 10

causes diarrhoea v.rarely

Question 11

adult diarrhoea - causes

Answer 11

Johne’s Disease (MAP)
Sub Acute Rumen Acidosis (SARA)
Salmonella

Question 12

Johne’s disease

Answer 12

hosepipe diarrhoea
highly infectious
Mycobacterium avium subspecies paratuberculosis (MAP)
MAP

Question 13

MAP 1

Answer 13

In clinical cases it causes severe diarrhoea and weight loss in adult cows
affected adult cows are infectious esp faeces
No treatment or cure – need to be culled on humane grounds
Potentially a zoonosis- MAP may be involved in Crohn’s Disease an inflammatory bowel disease in humans

Question 14

MAP 2

Answer 14

Infection is usually acquired by youngstock but it only becomes clinical several years later
Control largely relies on preventing young animals becoming infected - faeces + infected colostrum
Subclinical Disease is hard to detect.
It is difficult to identify subclinically affected animals due to issues with Lab tests

Question 15

MAP - prevention

Answer 15

Prevent calves getting infected
Prevent calves drinking infected colostrum from infected dam.
Avoid pooled colostrum
Prevent calves getting contaminated with adult faeces
Identification of subclinical infected adults difficult- lab test issues

Question 16

diagnosis of MAP

Answer 16

Blood Test (ELISA) has Low Sensitivity but High Specificity
Many infected cows are not detected by blood test
A positive test is reliable
Milk test also available
Diagnosis is difficult when screening for infected cows
In clinically infected cows tests have a much higher sensitivity