Neonatal Calf Diarrhea Flashcards
what is calf diarrhea
rapid movement of fluids through the intestines resulting in poor absorption of water, nutritive elements and electrolytes
may be bloody, watery or yellow or generally of a consistency looser than normal
why worry about calf scours
Scouring calves are expensive:
- Calf losses
- Treatment costs
- Time costs
- Reduced live weight gain
Calf welfare
Humans can catch some of the bugs that cause diarrhea in calves —> public health concerns
Antibiotic resistance issues
what is the mainstay treatment of calf scours
fluids
how do you prevent calf scours (2)
- boosting the calf’s immunity and resistance to disease
- minimizing infectious pressure
how do you boost the calf’s immune and resistance to disease
Calves are born without protective, disease-fighting proteins called antibodies or immunoglobulins (IgGs)
Calves absorb IgGs through their gut wall into their blood in the first 6-12 hours of life when they are fed enough, good quality colostrum early enough
This enables them to fight infection
when should you give colostrum
6-12 hours of life allows the best absorption of colostral antibodies
how often should you feed calves
fed twice daily for first 3 weeks of life as their stomach capacity is only 1.5-2L (SID not enough)
how should you store colostrum
in a pail with a lid and stirred often
fridge or freezer when not using
which cows will not supply good colostrum
heifers and sick cows won’t have as antibody rich
when should colostrum be collected from dam
milked asap after calving
what volume of colostrum is need as first feed
2L
how do you minimize infectious pressure in dairy (5)
- should be dry and draught free with good ventilation, partitions between calf pens should be solid
- clean dry bedding, replaced completely between seasons and refreshed during
- calves need min of 1.5m^2. no moree than 100 calves/shed and no more than 20 calves/pen
- all in all out
- calf housing should be at least 20m from milking shed
how do beef calves become infected with scour pathogens
mature beef cows carry the scours pathogens and shed the pathogen on the ground in manure. Newborn calves often pick up the pathogen and may not become sick, but their guts serve as pathogen-multipliers
these calves shed an increasing load of pathogen and newborn calves pick these pathogens up –> dose load is overwhelming
And if a beef herd calves on the same area year after year, the soil can also be contaminated with scour-causing pathogens.
how do you prevent scours in beef herds
sandhills system
So by keeping the more vulnerable newborn calves on clean ground away from the higher-risk two-week and older calves, the risk of a scours outbreak is greatly reduced.
how should you manage sick calves
- quarantine: bought in animals
- feed sick calves last and use separate feeder
- remove sick calves promptly from healthy ones and move them
- biosecurity: clean boots, overalls
what is secretory diarrhea
electrolytes excreted due to altered electrolyte pumps and water follows
what is osmotic diarrhea
water drawn into intestinal lumen
what is malabsorptive diarrhea
intestinal lining damaged
can no longer absorb
what pathogen causes small intestinal bacterial overgrowth
e coli
what causes acidosis
bacterial fermentation in GI tract –> D lactate
what are bacterial causes of scours
Salmonella
E. coli
Campylobacter
what are the viral causes of scours
Rotavirus
Coronavirus
what are parasitic causes of scours
Coccidiosis
Cryptosporidium
Worms
what is nutritional scours
due to changes in feeding freq or temp
no infectious causes
what type of bacteria is e coli (ETEC)
enterotoxin
gram negative faculatatively anaerobic rod bacteria found in environment
what is the pathophysiology of E coli and what type of diarrhea does it cause
Hypersecretion/non-absorption of fluid in distal small intestine (low pH kills bacteria)
K99 antigen allows binding to intestine
Heat stable toxin causes Cl and bicarb secretion —> water follows by osmosis
secretory and osmotic diarrhea
what age does E coli affect
<5 days
older have lower abdominal pH so its destroyed
what are the signs of e coli
Young (<5d)
Profuse foul smelling scour
Sick calf
+/- blood
+/- pyrexia
Wet mouth
Distended watery abdomen
what vaccine is available for E coli
Scourgard (Zoetitis)
Scour Bos (Elanco)
OR in UK
Rotavec corona and lactoserum (locatim)
what other e coli can cause scours
enteropathogenic e coli (EPEC)
enterohemorrhagic e coli (EHEC) aka verocytoxin producing e coli (VTEC) shiga toxin (verotoxin)
what scours do EPEC, EHEC cause
scour with blood, older calves
what salmonella spp cause scours
dublin
typhimurium
what age does salmonella affect
any
mainly <2 months
how do calves get salmonella
environmental (carrier animals) or mothers milk
what is the pathophysiology of salmonella
Engulfed into intestinal lymphoid cells, massive inflammatory response
what type of diarrhea does salmonella cause
malabsorption/osmotic endotoxin
what are the signs of salmonella
Pyrexia
+/- blood
Septicaemia
Vascular necrosis
Other signs in herd
- Adult scours
- Abortion
Death quickly
what is seen on PM with salmonella scours
ulceration of gall bladder
what vaccine is available for scours
Bovivac S
what age does rotavirus affect
5-21 days
how do calves get rotavirus
adult immune carriers
environment
found in normal calves
what is the pathophysiology of rotavirus
Invade enterocytes
Replicates then kills cell —> flattens the enterocytes so they cannot absorb any nutrients
what kind of diarrhea does rotavirus cause
secretory
loss of surface area
what are the signs of rotavirus
Older
White scour
Dehydrated
No blood or septicemia
what vaccine is available for rotavirus
Scourgard (Zoetitis)
Scour Bos (Elanco)
what is the pathophysiology of coronavirus
Proximal SI then spreads
Becomes intracellular
Infects mature enterocytes and crypt cells
similar to rotavirus
what age does cryptosporidium affect
1 week - 3 months
what is the source of cryptosporidium
protozoa in environment
what is the pathophysiology of cryptosporidium
Invagination of luminal membrane (intracellular but outside cytoplasm)
Villous atrophy
Crypt hyperplasia
Increased cell permeability
Apoptosis
what type of diarrhea does cryptosporidium cause
malabsorption/osmotic
what are the signs of cryptosporidium
less severe systemic signs
dehydrated
no blood or septicemia
what is the issue with treating cryptosporidium
its intracellular
hard for drugs to reach
what specific product is licensed for cryptosporidium
halofuginone = halocur
how do you disinfect the environment to get rid of cryptosporidium
ammonia based
what age does coccidiosis affect
3 weeks to 3 months
what is the pathophysiology of coccidiosis
Rupture of enterocytes
what type of diarrhea does coccidiosis cause
malabsorptive/osmotic
what are the signs of coccidiosis
Older
Black/bloody scour
Abdominal pain
Tenesmus
what are the species of coccidiosis and their virulence
Species vary in virulence (Eimeria bovis, Eimeria zuernii, Eimeria alabamensis)
Adult immunity
what is necrotic enteritis
7-10 week old beef calves
at grass
etiology unknown
what are the clinical signs of necrotic enteritis
pyrexia
acute diarrhea
dysentery
anemia
what is the pathophysiology of necrotic eneteritis
ulcerative
what is the morbidity, and mortality of necrotic enteritis
low morbidity <10%
high mortality 80%
what age does clostridium perfringens type C cause scours
7 28 days
what are the signs of clostridium scours
sudden death
blood tinged diarrhea
how do you diagnosed what the cause of scours is
Test a group of calves for all major pathogens (relevant to the age of sick calves( to get the complete picture
If not enough untreated calves available, could consider samples from calves treated with antibiotics — risk failing to culture Salmonella
Potentially could also take samples from slightly younger in contact calves as shedding for Rotavirus and Crypto will often occur before clinical disease
why is diagnosis important
Specific treatment for E. coli, Salmonella, cryptosporidium, coccidia
Preventative vaccine for rotavirus, coronavirus, E. coli, salmonella
But regardless of the cause the mainstay of any calf diarrhea treatment plan is fluids
how would you pathogen test
Clinical clues might help in 1st instance
Fecal sample
- Culture (bacteria)
- Virology (coronavirus/rotavirus)
- Parasitology (cocci and crypto)
Calf side tests (ELISA)
PM
Histopathology
how do you interpret pathogen testing
Hard to interpret —> does presence of pathogen = disease?
Often mixed infections
Does the pathogen matter
Before you test — think will the outcome of this test change the way I manage this individual or group in future?
Often farmer will ask “where did that come from?”
It was there the whole time
what are the treatment options for calf scours
Rehydration is critical:
The infectious organism will very rarely kill the calf, but dehydration will kill the calf
Fluid therapy should be mainstay of any calf scours treatment protocol
what are the consequences of scouring
Dehydration/hypovolemia
Azotemia (reduced renal perfusion)
Electrolyte loses (Na, Cl)
Acidosis (D-lactate from small intestinal bacterial overgrowth, L-lactate from hypoxia and bicarbonate lost)
Hyperkalemia (hydrogen exchanged for potassium) = cardiac arrhythmia = death
how do you assess the individual calf
no time to wait for diagnostics
clinical exam:
Demeanour:
- Suckle reflex*
- Recumbency*
- * = signs of acidosis
Temperature: ****
- Pyrexic (>39.5ºC)
- Hypothermic (<38.6º)
Respiratory rate
Nature of scour — blood?
how do you measure dehydration
Eyeball sunniness
How quickly the skin returns to normal after tenting
Mucous membrane moisture
what % of dehydration is considered fatal
12-14%
describe how a calf would appear
<5%
6-8% (mild)
8-10% (moderate)
10-12% (severe)
>12%
how does metabolic acidosis present in the calf
Progressive depression
Decreased suckle reflex
Weakness and incoordination
Inability to stand or sit up
Coma
Finally… death
why does metabolic acidosis occur in calves with diarrhea
Intestinal loss of sodium
Loss of bicarbonate into the gut
Lactic acid production in shocked tissues
Volatile fatty acid production in the colon from partially digested food
what is D lactate
Produced by poor fermentation of CHO in intestines due to SI bacterial overgrowth
L-lactate anaerobic metabolism
Contributes considerably to neurological signs of acidosis
Not detected by hand-held lactate meter
how do you assess the extent of acidosis
if the calf is able to stand, <7% dehydrated and no acidosis signs what fluid management would you do
oral fluids
if the calf is recumbent, 7-9% dehydrated and slightly acidotic what fluid management would you do
IVFT
if the calf is recumbent, >9% dehydrated and moderate to severe acidosis what fluid management would you d
IVFT + bicarb
how much fluid should you give
deficit = % dehydration x BW
maintenance = 50-100ml/kg/day
on-going losses = ?
how much fluid would you give a 50kg 10% dehydrated calf
DEFICIT = 10% x 50kg = 5L
MAINTENANCE = 50m x 50kg = 2.5L for 24 hours
2L for ongoing losses
TOTAL = 9.5L/day
(2x 5L bags)
which IV fluid should you use?
No perfect fluid
UK — none contain bicarb
Lactate/acetate = bicarb precursors = alkalinizing
Hypertonic
what fluid should you use for mild acidosis
Lactated/acetate fluids ex. lactated ringers
what fluid should you use for moderate acidosis
Lactated/acetate fluids + 15g bicarb
what fluid should you use for severe acidosis
Lactated/acetate fluids + 35g bicarb (OR bolus 10ml/kg of 8.4% hypertonic sodium bicarb)
if you are in doubt about what fluid what should you do
correct dehydration first
then decide about bircarb
describe the fluid types and what they contain
what fluid should you not add bicarb spike to
fluid containing Ca (hartmans/ringers) = precipitation
how do you administer bicarb
slowly ie AFTER shock rate
only admin bicarb in calves >7 days old that failed to respond to fluids only and that have clear signs of acidosis
what rate can you admin glucose
35ml/kg 10%
what rate should you administer fluids
initially 80ml/kg/hr or half volume in first hour
then 30-50ml/kg/hour
(for the prev example 4.75L of the total 9.5L in first hour = 4750ml = 95,000 drips/hour in a 20drip/min set =
1583 drips/min (divided by 60)
= 26 drips/sec
fully open for first hour then 13 drips/sec
should you admin bicarb at 80ml/kg/hour
no
what are the problems with setting up IV fluids
venopuncture difficult (low BP, dry skin)
calf moving
on farm
how do you set up IV fluids
Jugular (or ear vein)
Clip and prep
+/- cut down
+/- elevate hind end
Insert catheter (14-16g) through skin then into vein
Secure with suture via butterfly
Attach giving set (coiled) and secure via suture at ear
Confine animal +/- tie legs together
Fluid bag at heigh
Bailer twine, wire coat hanger
what should oral fluids contain
Sodium
Other electrolytes (chloride, potassium)
High strong ion differences
Energy source
Alkalinizing agent (acetate and propionate = precursors) ideally not bicarb = milk clot formation altered, high pH, facilitates E. coli SIBO
what is key when giving oral fluids
keep the calf on milk!
oral fluids are not enough to sustain calf
what are the features of the ideal oral fluid
why is mixing milk and electrolyte products not recommended
The electrolyte should not be mixed with milk and the two feeds should be separated by at least 1.5 hours
Scouring calves need fluid replacement and separating the electrolytes and milk feeds allows faster rehydration
Feeding oral electrolytes and milk together may interfere with casein coagulation in abomasum
what is the treatment beyond fluids
Treat/prevent septicemia/bacteremia
Decrease number of coliform (SIBO)
Encourage immunity/resistance
Provide nutrition
Control pain
when would antimicrobials be indicated
Yes if:
Systemic signs (pyrexia, decreased appetite, lethargy — E. coli)
Blood/mucosa present
Suspect Salmonella or E. coli
what antimicrobial would you use for scours
Licensed (often off label)
Gram negative bactericidal
Parenteral rather than oral
Ex. TMPS (AKA sulfadimethoxine)
what analgesia should you give
NSAIDs:
Analgesic/anti-inflammatory/anti-endotoxic agents
Meloxicam (0.5 mg/kg)
- Contraindicated in dehydrated calves! Only if corrected dehydration
- Decreased renal perfusion and nephrotoxicity
why are steroids not advised
diarrhea calves already have high steroid levels
immunosuppression
what is halofuginone
Not much evidence
Cryptosporadiostatic, reduces shedding but doesn’t kill ocysts
SID for 7d, orally
Not empty stomach
Administer in oral fluids
Toxic at 2x dose
what treatments can be given for coccidiosis
Decoquinate (Decoxx)
Diclazuril (Vecoxan) treatment and prevention in lambs, aid control calves
Toltrazuril (Baycox) prevent clinical signs, reduce shedding
Sulphonamides
what nursing should be done to calves
Isolate from other calves
Keep warm (jackets)
Access to fresh, clean water
Feeding of milk —> little and often
Monitor response to treatment
Other treatments:
Limited evidence for B vitamins, probiotics, protectants/absorbents, GI motility modifiers
what vaccinations are available
vaccinate mother antibodies in colostrum
but not a susbtitute for good management
rotavec corona
locatim (colostrum supplement)
E coli k99
60ml 4-12 hours after birth
