Scour in indoor cattle

Question 1

What are infectious and non-infectious causes of diarrhoea in cattle?

Answer 1

Infectious
- salmonella
- eimeria species
- rotavirus
- coronavirus
- johnes
- crypto
- e coli
- BVD
- rinderpest
- clostridium
- nematodes
- yersinia
- malignant catarrhal fever
- secondary to septicaemia

Non-infectious
- nutritional
- poisonous substances
- mycotoxins
- acidosis
- copper deficiency/toxicity
- cobalt +/or selenium deficiency
- secondary to Das, peritonitis

Question 2

What are differentials for infectious causes of diarrhoea in pre-weaning calves?

Answer 2

Within 14 days of age:
* Rotavirus
* E. Coli
* Coronavirus
* Cryptosporidium parvum

From a few weeks old:
* Eimeria species

Any age pre-weaning:
* Clostridium species

Question 3

What is the pathogenesis of clostridium perfrigens? What clinical signs are associated?

Answer 3

• Commensal of GI tract and soil
• Proliferates if sudden diet change
• Cx: death +/- severe D+
• Pathology: haemorrhagic enteritis, intestinal mucosal ulceration, D+ in intestines
• Pathophysiology: rapid bacteria overgrowth and enterotoxin release

Question 4

What is the most common differential for infectious causes of diarrhoea in post-weaning calves?
What are predisposing factors?

Answer 4

Eimeria species (3 weeks to 6 months old)

Predisposing Factors:
High stocking densities, poor hygiene, mixed aged groups, stress factors, wet and warm weather, mixing calf groups

Question 5

Which species of Eimeria affect post-weaning calves?
What clinical signs are associated? Describe pathogenesis. Do calves develop immunity?
How can it be prevented?

Answer 5

Which species?
* Numerous species of Eimeria – not all are pathogenic!
* Eimeria bovis
* Eimeria zuernii
* Eimeria alabamensis

Clinical Disease: D+ and poor DLWG

Why:
* Infection location: cecum, colon and the terminal part of the ileum
* Mucosa = congested, oedematous and thickened with haemorrhages; later on sloughed away

Immunity: Yes
* depends on the quantity of oocysts picked up during the primary infection
* Species specific!

**Prevention: **
* HYGIENE: Bedding management, Stocking densities, Group management etc
* MEDICAL: Oral Drench: Diclazuril, Toltrazuril, Decoquinate in feed

Question 6

How is Eimeria diagnosed in calves? How is it treated?

Answer 6

**Diagnostics: **
McMasters test

**Treatment: **
* Supportive therapy
* Diclazuril: 1 mg diclazuril per kg bodyweight
* Toltrazuril: 15 mg toltrazuril/kg body weight

Question 7

What are the 2 most common differentials for infectious causes of diarrhoea in adult cattle?

Answer 7

• Winter dysentery (coronavirus)
• MAP (Johnes)

Question 8

What is the disease presentation of winter dysentery? Describe pathophysiology.

Answer 8

Disease presentation:
* Highly contagious – most of the herd
* Short-lived explosive D+
* Predominantly in the winter
* Cattle in close confinement
* Most cattle are seropositive
* Virus can cycle around cattle of all ages

Pathophysiology:
* Faeco-oral transmission + suspected change in the rumen microbiome
* Colonisation of small intestine and colon
* Voluminous D+ from hypersecretion due to inflammatory response
* Destroy epithelial cells

Question 9

Which Salmonella species and serovars are most commonly found? What are risk factors for infections?

Answer 9

• Salmonella enterica subsp enterica serovars (serotypes) clinical importance in ruminants
• Dublin = host adapted
• Commonly isolated = Newport, Typhimurium, Mbandaka

Risk factors
dairy cow
- state of immune system
- natural immunity
- vaccination
- gut health

Salmonella bacterium
- amount of bacteria consumed
- virulence of serotype

Environement
- stressors
- heat stress
- transportation
- pen moves
- diet changes
- calving
- overcrowding
- hygiene of feed and water
- nutrition

Question 10

Describe pathophysiology of Salmonella. What secondary diseases can be caused?

Answer 10

1. Once ingested,Salmonellaattaches to mucosal cells and is capable of destroyingenterocytes
2. Stimulate inflammatory response and ingested by macrophages and PMNs
3. Rapid dissemination throughout the body including lymph tissue
4. Bacteraemia

**Secondary **
- Septicaemia
- enteritis
- abortion

Diagnosis
* Individual faecal culture using enrichment and selective media
* Composite faecal sampling
* PCR: faeces, milk, tracheal or bronchoalveolar lavage fluid
* Blood, trans tracheal wash, BAL, or joint fluid culture when (suspected bacteriemia)
* Culture or post-mortem sample: gastrointestinal tract, mesenteric lymph node, bile and lung
* Environmental culture
* Immunoassorbent assay: serum or milk

Question 11

What is SARA? What is it? What clinical signs are associated?

Answer 11

Sub Acute Ruminal Acidosis
Characterized by repeated bouts of low rumen pH, but unlike the situation with acute acidosis, the pH recovers after each bout. These bouts of low pH typically last for several minutes to several hours.

Clinical signs
* BCS loss
* Variable faecal consistency
* Reduced:
* Rumen contractility
* Rumination
* Feed intake
* Rumen fill
* Periodic anorexia
* Increased faecal contamination of tail, rump and perineum
* Ejected cud balls
* Milk yield suppression
* Milk fat suppression
* Liver abscess
* Caudal vena cava syndrome (epistaxis)

Question 12

What predisposes cows to SARA?

Answer 12

Excess starch
- high concentrate feeding
- slug feeding

Decreased intakes
- heat stress
- poor cow comfort
- poor transition cow management

Lack of fibre
- dietary sorting
- low fibre in the diet

Question 13

How is SARA diagnosed? How can it be monitored?

Answer 13

Rumen fluid sampling
- stomach tube (saliva can affect the pH)
- rumenocentesis

Monitoring
* Regular Monitoring: Regularly monitor the rumen pH, especially in high-risk periods such as post-partum and during diet changes
* Manure Observation: Observe manure consistency. Loose manure with undigested grains can be an indicator of SARA
* Sensors: drop in rumination and rumen pH (indwelling boluses)

Question 14

How can SARA be prevented?

Answer 14

Diet management:
* Gradual increase of concentrate in the diet post-partum
* Adequate intake of physically effective fibre (peNDF)
* Use of starches that are slowly fermentable

Feed space Sufficient feeding space for each cow
Feed Additives: Use feed additives like buffers (e.g., sodium bicarbonate)

Question 15

What mycotoxins cause diarrhoea in cattle? What clinical signs are associated? How can they be diagnosed? How can it be prevented?

Answer 15

Causes:
* Fusarium, Aspergillus and Penicilliumare in silage
* Deoxynivalenol and zearalenone were the most commonmycotoxins in UK

Reported clinical signs: loss of appetite, reduced milk yield or poor weight gain, feed refusal, diarrhoea, pyrexia, pruritis, bleeding and ill thrift

Diagnosis is difficult due to the lack of specific clinical signs and overlapping symptoms of other metabolic diseases, such as acidosis in cattle

Prevention:
* Harvesting crops as early as possible in the season (especially forage maize) avoiding soil contamination
* Minimising top spoilage through the use of an oxygen barrier covering film
* Mycotoxin binder in TMR