11.3.2: Scour in indoor cattle Flashcards
Causes of diarrhoea outbreaks in adult cattle
- Acidosis - seen at population level
- Coronavirus - can cause winter dysentery
- Mycotoxins - can be seen at herd
- Salmonella - always on the ddx list
True/false: Clostridia is a common cause of diarrhoea in adult cattle.
False
Clostridia tends to affect younger animals
True/false: coccidiosis is a common cause of diarrhoea in adult cattle.
False
Coccidiosis affects younger animals; doesn’t cause problems in adults.
True/false: BVD can cause outbreaks of diarrhoea at a herd level.
False
BVD doesnt really tend to cause diarrhoea except sometimes in PI animals - this is at individual rather than herd level.
Salmonella in cattle is
a) reportable
b) notifiable
a) reportable
Rinderpest in cattle is
a) reportable
b) notifiable
b) notifiable
Ddx for infectious diarrhoea in housed cattle
1
Ddx for infectious diarrhoea in housed cattle
2
Ddx for infectious diarrhoea in housed cattle
3
Ddx for infectious diarrhoea in housed cattle
4
Ddx for infectious diarrhoea in housed cattle
5
Ddx for infectious diarrhoea in housed cattle
6
Differentials for diarrhoea in pre-weaning calves
Any age - Clostridium species
Within 14 days old - rotatvirus, coronavirus, E. coli, Cryptosporidium parvum
From a few weeks old - Eimeria
What species of Clostridia cause diarrhoea and how would this present?
Clostridium pefrigens Types A, B, C and D
* Commensal of GIT and soil
* Proliferates if sudden diet change, usually increase in starch
* Pathophysiology: rapid bacteria overgrowth and enterotoxin release
* Clinical signs: death ± severe diarrhoea
* Pathology: haemorrhagic enteritis, gas filled (A), intestinal mucosal ulceration/ abomasal ulcers (B), diarrhoea in intestines, signs of peritonitis (C and D)
Who is susceptible to Eimeria? When does shedding occur?
3 weeks to 6 months calves
Shedding can occur lifelong in low numbers
Clinical signs of Eimeria (coccidiosis)
- Diarrhoea
- Poor DLWG
- Can get rectal prolapse due to persistent straining -> fix with epidural and purse string suture
Pathology of Eimeria
- Infection location: caecum, colon, terminal part of ileum
- Mucosa = congested, oedematous and thickened with haemorrhage; later on sloughed away
- Casts in faeces = sloughed mucosa
True/false: coccidiosis is a particular concern in beef and sheep, and co-grazing species can pass the infection between each other.
False
Eimeria is species-specific so infection cannot pass from cows to sheep and vv.
Which animals are particularly at risk for diarrhoea caused by Clostridium perfringens?
Tends to be more prevalent in beef and sheep
* Vaccination against clostridial diseases common in these e.g. Heptovac
True/false: animals can develop immunity to coccidiosis.
True
* Depends on the quality of oocysts, picked up during the primary infection
Diagnosis of coccidiosis
McMasters test
Treatment and prevention of coccidiosis
Treatment - supportive therapy
Prevention
Medical: oral drench - diclazuril, toltrazuril, decoquinate in feed (may not be considered AMR compliant)
Prevention: bedding management, stocking densities, group managements
Risk factors for coccidiosis
- High stocking densities
- Poor hygiene
- Mixed age groups
- Stress factors
- Wet and warm weather (calves turned out in poor weather will huddle and create high stocking densities)
- Mixing calf groups
Causative agent and disease presentation of winter dysentery
Causative agent: coronavirus
Disease presentation
* Highly contagious - most of herd
* Short-lived explosive diarrhoea
* Predominantly seen in winter
* Cattle in close confinement
Testing for winter dysentery
Caused by coronavirus -> same pathogen that causes diarrhoea in calves and mild BRD in post-weaning calves.
* Most cattle are seropositive
* Virus can cycle around cattle of all ages
* Morbidity is high, mortality is low -> consider if likely to have caused disease based on presentation
Pathophysiology of winter dysentery
- Faeco-oral transmission and suspected change in rumen microbiome
- Colonisation of small intestine and colon
- Voluminous diarrhoea from hypersecretion due to inflammatory response
- Destroys epithelial cells
Treatment of winter dysentery
Supportive, NSAIDs
Eimeria (coccidiosis)
Characteristics of Salmonella infection
Salmonella = zoonotic and reportable!
* Multiple different species and serovars e.g. S. dublin, tymphimurium
Can cause:
* Abortion (can see abortion storms)
* Enteritis
* Septicaemia
Risk factors for Salmonella
- Open herd/ buying in
- High stocking density helps with spread of disease once it is on the farm -> predispses to outbreak
- Important to control feed stores/ wildlife/ rodents
- Consider contamination of water e.g. borehole water
Diagnosis of Salmonella
- Faecal sampling if outbreak of diarrhoea
- If abortion: send off full foetus and placenta -> for culture
- Ring APHA and ask what tests to do
- (Salmonella is reportable and zoonotic!)
Pathophysiology of Salmonella
- Once ingested, Salmonella attaches to mucosal cells and is capable of destroying enterocytes
- Stimulate inflammatory response and ingested by macrophages and PMNs
- Rapid dissemination throughout the body including lymph tissue
- Bacteraemia
Treatment plan for Salmonella
- Gram negative bacteria -> TMPS (submit for C&S; used to use enrofloxacin but now it is CIA)
- Reduce destruction of mucosal tissue -> NSAIDs e.g. meloxicam
- Correct likely metabolic acidosis -> Fluids -> oral if pos, IV fluids in septic/down calf, hypertonic saline in cow then give bucket of water
Healthy rumen pH
5.6-6.5
Healthy time spent ruminating and volume of saliva produced
Time spent ruminating per day: 10-12 hrs
Volume of saliva produced >70L
Normal frequency of ruminal contractions
3 in 2 mins
End product of rumen fermentation
VFAs (propionate, acetate, butyrate)
Healthy rumen organisms per ml
10⁹ to 10¹¹ cfu/ml
1
2
3
5
6
7
8
9
10
Cause and pathogenesis of SARA
Risk factors for SARA
Excess starch
* High concentrate feeding (e.g. finishing unit)
* Slug feeding
Lack of fibre
* Dietary sorting
* Low fibre in diet (spring grass) -> not enough fibre in rumen = danger triangle of empty rumen
Decreased intakes
* Heat stress
* Poor cow comfort
* Poor transition cow management
True/false: dairy herds show a drop in milk fat on spring grass.
True
Liver abscesses might indicate a subclinical problem in the herd. What is this?
Liver abscesses -> indication of SARA as associated with bacterial translocation
* Liver abscesses can lead to CVCS
Diagnosis of SARA
- Rumen fluid sampling either by stomach tube or rumenocentesis
Prevention of SARA
- Mitigate the risk factors: provide enough fibre in diet, good chop length, good cow comfort to allow rumination
- (Consider fibre to starch balance in diet and if cows are happy)
Causes, clinical signs, diagnosis and prevention of mycotoxicosis
Top differential?
Coccidiosis
Infectious cause (pyrexia) but calves fairly bright with no sepsis.
Cryptosporidium is very unlikely after 2-3 weeks old
Top differential?
SARA
* Multiple animals affected but too old for many infectious causes
* Too young for Johne’s, unlikely to be BVD given how many animals affected
* Salmonella unlikely as would expect pyrexia and animals to be more unwell
Top differential?
Salmonella
* Pyrexia
* Mortalities
* Blood in faeces
* Abortion present
Top differential?
Johne’s
* Individual cow affected
* Older cow
* Signs of protein losing enteropathy: decreased BCS, watery faeces, mild brisket oedema
