Farm Animal Diarrhoea

Question 1

What are the factors that are involved in development of farm animal diarrhoea?

Answer 1

Pathogens Calf factors (immune status, stress) Environment and Management

Question 2

What are the pathogens that can cause farm animal diarrhoea?

Answer 2

E. coli Coronavirus Rotavirus Cryptosporidium Salmonella Coccidiosis Can also get mixed infections

Question 3

What is ETEC?

Answer 3

Enterotoxigenic E.coli

Question 4

What age to animals get ETEC?

Answer 4

Within the first 5 days post partum

Question 5

How does an animal become infected with ETEC? And what other pathogen is associated with infection?

Answer 5

Ingestion, the bacteria colonise the small intestine. Rotavirus is commonly associated with this type of infection.

Question 6

What genes are needed for E.coli to become pathogenic and how are they transmitted between bacteria?

Answer 6

Adhesive fimbrae and enterotoxin genes Conferred by plasmids, these can be on seperate plasmids or on the same plasmid

Question 7

Which adhesive fimbrae serotypes of ETEC are zoonotic?

Answer 7

CFA I and CFA II

Question 8

What is the mechanism of diarrhoea in ETEC infected animals?

Answer 8

Labile Toxin binds to Gs ADP-R subunit and leads to increased cAMP and activation of the CFTR (Cloride) channel. Cl is therefore secreted and Na and H20 follow this. Therefore there is a secretory diarrhoea.

Question 9

How can ETEC infection lead to death?

Answer 9

Dehydration, metabolic acidosis and electrolyte loss can be fatal.

Question 10

What are the two types of toxin of ETEC and are both vaccinatable against?

Answer 10

Labile Toxin - can vaccinate with (i.e. in colostrum) Stable toxin - too small to elicit an immune response

Question 11

How is ETEC determined from a faecal smear/culture.

Answer 11

Adhesive fimbrae AND enterotoxin genes must be demonstrated.

Question 12

How does rotavirus diarrhoea differ to that of ETEC induced diarrhoea?

Answer 12

Rotavirus results in malapsorbtion rather than active water secretion.

Question 13

How is rotavirus related to mortality and how will general hygiene relate to its potential to infect?

Answer 13

High morbidity but low mortality. It persists in the environment and is shed by adults and older calves.

Question 14

Where is coronavirus located in the gut?

Answer 14

Ileum, caecum and colon.

Question 15

When is salmonella culture significant?

Answer 15

ALWAYS and it is a REPORTABLE disease to the AHVLA.

Question 16

How does cryptosporidium cause disease?

Answer 16

It causes villous atrophy resulting in a malabsorpative diarrhoea.

Question 17

When does coccidiosis need to be investigated?

Answer 17

In older weaned calves (>3 weeks) that are losing weight as well as having diarrhoea/generally not doing well. Other signs include tenesmus and blood stained faeces.

Question 18

How are the pathogens describes diagnosed?

Answer 18

With faecal SAMPLE not swabs sent to a competent laboratory. Typing is necessary.

Question 19

Is the appearance of diarrhoea helpful in determining disease?

Answer 19

No

Question 20

What is the most common cause of diarrhoea on a farm?

Answer 20

Dietary issues.

Question 21

At what age are the different pathogens likely to be the cause of diarrhoea?

Answer 21

Question 22

What calf factors affect the chances of infection?

Answer 22

Accessability to colostrum

Dystocia

Competition

Cow factors - quality of colostrum, down cow, allowing to suck?

Question 23

What would a perfect individual cow pen be like?

Answer 23

• Water and feed buckets outside of pens to avoid faeces getting into them - also clear out regularly to prevent pathogen build up
• Not too close contact between calves - defecation into surrounding pens
• Litter cleared out not just deep litter
• Clean/seperate calving pens
• Ventilation

Question 24

What should calves be fed?

Answer 24

Water - calves drinking milk for thirst will have it enter the rumen which will lead to diarrhoea.

Milk replacer

Cake for intestinal villi development

Question 25

What can cause diarrhoea in growing/adolescent animals?

Answer 25

• Endoparasites
  
  • Ostertagia
  • Coccidia
  • Fluke
• Nutritional
  
  • Rumen accidosis
  • Copper deficiency
• Infectious
  
  • Salmonella
  • Mucosal disease

Question 26

What can cause diarrhoea in adult cows?

Answer 26

• Infectious
  
  • Johne’s disease
  • Salmonella
  • Coronavirus
• Nutritional
  
  • SARA
• Parasitic
  
  • Fluke
  • Ostertagiosis

Question 27

What should one do when assessing diarrhoea/general farm health?

Answer 27

Inspect faecal appearance and particle size on the whole farm

Question 28

What causes Johne’s disease?

Answer 28

Mycobacterium avium paratuberculosis (MAP)

Question 29

What is the treatment for MAP?

Answer 29

There isn’t one. Adult cows with Johne’s will remain infectious. They should be culled on humane grounds. They could also be bred to beef.

Question 30

What age animals can be affected by MAP?

Answer 30

Young animals can be infected but disease only occurs in cows >2 years old.

Question 31

How can infection spread be prevented/controlled?

Answer 31

• Prevent faeces from older animals
  
  • Calf pens/calving pen
  • Don’t spread slurry
• Stop infected colostrum being fed
  
  • Dont pool colostrum
• Prevent in utero
  
  • Detect subclinical adults
  • Dont buy infected stock
    *

Question 32

What are the different tests for Johne’s disease and their effectiveness?

Answer 32

ZN stain - sensitivity and specificity low

ELISA - low sensitivity but high specificity

PCR faecal - same as ELISA

Faecal culture - gold standary but only 60% sensitivity

Necropsy - 100% both