3 + 4: Diarrhoea in Calves Flashcards
What % of fluid in the gut is from secretion?
80%
What % of water in the gut is absorbed?
95%
What kind of diarrhoea does ETEC cause?
Intestinal hypersecretion from enterotoxins
What kind of diarrhoea do rotavirus and coronavirus cause?
Malabsorptive from villous atrophy
Which part of the intestine does osmotic diarrhoea affect?
Diffuse intestinal
What causes osmotic diarrhoea?
CHO malabsorption including dietary intolerance, saline laxatives, overfeeding of normally digestible CHOs
What is the most common cause of osmotic diarrhoea?
Viruses
What happens to osmotic diarrhoea after feeding?
Gets worse
Why is faecal pH acidic in osmotic diarrhoea?
Due to lactic acid
Why does volume increase less in osmotic diarrhoea?
Due to compensatory absorption
What is the osmolality of the stool like in osmotic diarrhoea?
High osmolality stool with an “osmolal gap” between electrolytes and sugars
What causes secretory diarrhoea?
Bacterial enterotoxins
What is the mucosa like in secretory diarrhoea?
Inflammation
What is the hydrostatic pressure like in secretory diarrhoea?
Elevated
What is osmolality like in secretory diarrhoea?
Normal, accounted for by electrolytes
What is volume like in secretory diarrhoea?
Very large, but absorptive mechanisms intact
What is pH like in secretory diarrhoea?
Normal or alkaline
What is the function of the villi?
Enzymes for absorption
What is the function of the crypt cells?
Only secrete Cl- and HCO3-, Na and water follow
Normally, is villous absorption or crypt secretion greater?
Villous absorption
Why does villous atrophy give increased secretion?
Crypt hyperplasia
Which toxins mediate ETEC hypersecretion?
ST and LT
How does ETEC enter the intestine?
Attaches to the mucosa in large numbers
Which part of the intestine is overwhelmed in ETEC?
Absorptive capacity of the LI
Why can you use glucose-electrolyte solutions in ETEC?
Doesn’t affect substrate-linked Na absorption
What happens to the microvilli in EHEC?
Lost
What kind of virus is rotavirus?
dsRNA
What rotavirus group affects calves?
A
What kind of scour does rotavirus give?
“White scour”, mild
How many farms have rotavirus?
Endemic on most farms
At what age is rotavirus peak incidence?
10 days
What is the incubation period of rotavirus?
15 hours to 5 days
How long does rotavirus disease last?
4-8 days
How can you prevent rotavirus?
Vaccinate dam, manage exposure, increase antibody protection
Is rotavirus or coronavirus more common?
Rotavirus
Is rotavirus or coronavirus more severe?
Coronavirus
What kind of virus is coronavirus?
ssRNA
What kind of scour does coronavirus give?
Watery yellow with clots and mucous
What age calves get coronavirus?
1-3 weeks
What is the incubation of coronavirus?
20-30 hours
How long is the course on infection in coronavirus?
4-5 days
Which part of the intestine is affected in coronavirus?
LI
Is there a vaccine for coronavirus?
None
How do you diagnose coronavirus?
EM of faecal sample
How do you identify which E Coli strain you are dealing with?
Fimbrial antigens
Where is the extra-host maturation stage in crypto?
None
Which age calves get crypto?
7-14 days
At which age does crypto infection peak?
14 days
How long is the incubation of crypto?
2-4 days
What kind of scour does crypto give?
Watery green with mucous and sometimes blood
How many days does crypto infection last?
2-14, usually 7
What is morbidity and mortality like in crypto?
High morbidity, low mortality
Which part of the intestine does crypto affect?
LI
What do the villi look like in crypto?
Villi surface heavily infected, exfoliated enterocytes at tips
How useful are coccidiastats in crypto?
Limited
What disinfectants is crypto sensitive to?
Ammonia, formalin, freezing, steam
How do you diagnose crypto?
See oocysts in faecal smears
How do you treat crypto?
Self-limiting
Which two infections often occur together leading to high moebidity?
Crypto and rotavirus
What are the most common causes of disease in dairy/suckler beef?
Crypto and rotavirus
In which units is Salmonella mostly seen?
Calf rearer
What % of weaned calves have Campylobacter?
80%
What kind of scour does persistent peri-weaning calf diarrhoea give?
Grey-brown
What age calves get persistent peri-weaning calf diarrhoea?
3-10 weeks
What causes persistent peri-weaning calf diarrhoea?
Poor quality milk replacer
What is morbidity and mortality like in persistent peri-weaning calf diarrhoea?
High morbidity, low mortality
How do you treat persistent peri-weaning calf diarrhoea?
Try diet, management etc
Which kind of calves get necrotising enteritis?
Beef suckler calves
What age calves get necrotising enteritis?
2-4 months
What time of year do you see necrotising enteritis?
June/July (the Spring-born calves at pasture)
What is morbidity and mortality like in necrotising enteritis?
Low morbidity, high mortality
Why does necrotising enteritis look like BVDV?
Recurs every year
What kind of scour does necrotising enteritis give?
Profuse, muco-haemorrhagic
After how long does death occur in necrotising enteritis?
7-10 days
How do you treat necrotising enteritis?
Symptomatically
How does loss of ECF eventually lead to death?
Via acidosis to hyperK
What other problem does ECF loss give?
hypoNa
Which kind of calves in acidosis more pronounced in?
Older, depressed
Do you need severe dehydration to get acidosis?
No
Why is acidosis more common in older calves?
More able to hide illness than neonate
What does a Harleco apparatus do?
Allows immediate estimation of the acid-base status
How does a Harleco apparatus work?
Displaces CO2 with lactic acid
What is the acidosis like if there is less CO2?
More severe
What other conditions can you use a Harleco apparatus for?
Intestinal obstruction, toxic mastitis
How do you correct acidosis?
IV HaHCO3 (isotonic)
How many mmol HCO3 should you give?
200-400mmol spike
Which calves should you give IV fluids to?
Off suck, depressed, over 8% dehydrated
What happens to osmotic diarrhoea if you continue to feed?
get worse
How do you treat osmotic diarrhoea?
Withdraw milk and give oral fluids for 1-3 days if depressed and doesn’t want to suck or if faeces are acidic
How should you re-introduce feed during osmotic diarrhoea treatment?
After three days, re-introduce at 5% bodyweight for 24 hours
How do you treat malnutrition in osmotic diarrhoea?
If depressed, give high energy oral fluids
Do you withdraw milk in secretory diarrhoea?
No - no reason to
What pH are faeces in secretory diarrhoea?
Alkaline
How do you treat secretory diarrhoea?
Rehydrate with oral fluids (% dehydration x body weight)
Which secretory diarrhoea has good results following treatments?
Uncomplicated ETEC
Why are secretory diarrhoea cases with gut inflammation a challenge?
Absorption is decreased
Why should you consider IV glucose fluids in secretory diarrhoea?
Oral may exacerbate diarrhoea
Where is the majority of the electrolyte loss from?
ECF
Which electrolytes do you give if loss is from the ECF?
Na and Cl
What else must fluids contain as well as electolytes?
GLucose, and alkalinising agents e.g. bicarbonate, l-lactate, acetate
Which alkalinising agents should you not use in IV fluids?
Gluconate and d-lactate
What can overdosing bicarb give?
Alkalosis, or paradoxical cerebrospinal acidosis
What problems can hypertonic bicarb cause?
HyperNa or hyperosmolality causing CSF haemorrhage
What is ideal mmol/L of bicarb?
40-80
Why should you not use actual bicarb when feeding?
Interferes with digestion
What is a problem with giving hyperosmotic solutions?
Osmolality delays gastric emptying
What % of a calf’s energy requirement can fluids provide?
80%
How energy dense is fluids compared to milk?
46%
Why is Hartmann’s not good for severe cases?
Acidic and can’t add bicarb
So what should you use instead of Hartmann’s?
Just saline and bicarb
What % glucose should you give if the calf is emaciated?
5%
When is the only time a calf needs nutritional support in fluids?
Emaciated, or off milk for 3 days
Which are some potential issues with fluid overload?
CNS oedema, congestive heart failure, resp distress
Which fluids are especially dangerous for overload?
High Na or low protein
What is a problem with correcting hypoCa or acidosis in animals with decreased whole-body potassium?
Precipitates hypoK as increased renal excretion
