Neontal calf diarrhoea Flashcards
Calf diarrhoea or scours is defined as
the rapid movement of fluids through the intestines resulting in poor absorption of water, nutritive elements and electrolytes’
2 main causes of calf scours
VERY common
Underlying issues with management/husbandry
nutritional vs infectious
What is the mainstay treatment for calves with scour
Fluids
2 principles of preventing calf scours
BOOSTING THE CALF’S IMMUNITY AND RESISTANCE TO DISEASE
MINIMISING INFECTIOUS PRESSURE
How often to feed newly calved cow
Fed twice a day for the first 3 weeks of life as their stomach capacity is only 1.5-2 litres which means they won’t get enough feed if fed once a day from birth
Suggest ways to Minimising infectious pressure for a newly calved calf
Housing
- Dry and draught free with good drainage and ventilation systems. Partitions between calf pens should be solid
Hygiene
- Clean, dry bedding, replaced completely between seasons and refreshed during the season
Stocking density
- Calves need a minimium of 1.5m2. No more than 100 calves per shed and no more than 20 calves per pen
All in all out
- Calves should be moved around the shed as little as possible.
Location
- Calf housing at least 20metres from the milking shed
Pathophysiology of scour
Secretory
Electrolytes excreted (alter electrolyte pumps), water follows
Osmotic
Water drawn into intestinal lumen
Malabsorption
Intestinal lining damaged, can no longer absorb
Small intestinal bacterial overgrowth (SIBO) with Ecoli
Bacterial fermentation in GI tract = D lactate = acidosis
Suggest bacterial causes of scour
Salmonella
Ecoli
Campylobacter
Suggest viral causes of scour
Rotavirus
Coronavirus
Suggest parasitic causes of scour
Coccidiosis
Cryptosporidia
Worms
Clinical signs of calf with ecoli
= young (< 5d), profuse foul smelling scour, sick calf, +/- blood, +/- pyrexia, wet mouth, distended (‘watery’) abdomen
Path of E.coli
Hypersecretion/non-absorption of fluid in distal SI. Once colonised, travels proximally
1. K99 antigen - allows binding to intestine
2. Heat stable toxin - causes Cl and bicarb secretion. Water follows by osmosis
3. Secretory (and osmotic) diarrhoea
Clinical signs of calf with salmonella
Age = Any, mainly <2 months
Signs = pyrexia, +/- blood, septicaemia, vascular necrosis, other signs in herd (e.g. adult scours or abortion), death quickly
Is salmonella infection reportable
Yes!
Is salmonella zoonotic
Yes!
Path of Salmonella
Engulfed into intestinal lymphoid cells, massive inflammatory response
Malabsorption/osmotic, endotoxin
Clinical signs of calf with rotavirus
Age = 5-21 days
White scour, dehydrated (NO BLOOD OR SEPTICAEMIA)
Path of rotavirus
Invade enterocytes, replicates then kills cell, produces enterotoxin
(Loss of surface area) and secretory
Cause of death from rotavirus and coronavirus
Dehydration
Clinical signs of calf with cryptosporidium
Age = 1week – 3 months
Signs = less severe systemic signs, dehydrated
(NO BLOOD OR SEPTICAEMIA)
Path of cryptosporidium
Invagination of luminal membrane (intracellular but outside cytoplasm), villous atrophy, crypt hyperplasia, increased cell permeability, apoptosis
Malabsorption/osmotic
Clinical signs of calf with coccidiosis
Age = 3 weeks to 3 months, Adult immunity
Older, Black/bloody scour, abdominal pain, tenesmus
Path of coccidiosis
Rupture of enterocytes, Malabsorption/osmotic
Outline Pathogen Testing of sick cows
Clinical clues might help in 1st instance
Faecal sample
- Culture (bacteria)
-Virology (corona/rota)
- Parasitology (Cocci and crypto)
Calf side tests (ELISA)
PM
Histopath – need to be quick (30mins death to formalin)
Consequences of scouring
Dehydration/hypovolaemia
Azotemia (Reduced renal perfusion)
Electrolyte loses (Na, Cl)
Acidosis (D-lactate* from SIBO, L-lactate from hypoxia and Bicarb lost)
Hyperkalaemia (Hydrogen exchanged for potassium)
= Cardiac arrhythmia = Death
How do we measure dehydration?
Eyeball sunkeness
How quickly the skin returns to normal after ‘tenting’
Mucous membrane moisture
Demeanour
What percentage of dehydration is considered fatal
12-14% dehydration is considered fatal
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
4 criteria for measuring acidosis
- Suckle reflex
- Ability to stand
- Respiration (Normal-Increased)
- Palpebral reflex
What treatment is appropriate for a calf that is Able to stand, < 7% dehydrated, No acidosis signs
ORAL FLUIDS
What treatment is appropriate for a calf that is Recumbent, 7-9% dehydrated, slight acidosis
IVFT
What treatment is appropriate for a calf that is Recumbent, > 9% dehydrated, moderate to severe acidosis
IVFT and BICARB
How much fluid? – 50kg calf, 10% dehydrated
10% x 50kg = 5 litres for deficit
50ml x 50kg = 2.5 litres for 24 hours maintenance
?2l for on-going losses
TOTAL VOLUME = 9.5 litres/day
Why Don’t add Bicarb spike to fluid containing Calcium i.e. hartmans/ringers
Precipitation
What is the General rule to administering bicarb
> 7 days old that failed to respond to fluids only and that have clear signs of acidosis
Fluid rate
Initially 80ml/kg/hour or half volume in 1st hour
(DO ADMIN BICARB AT 80ML/KG/HOUR)
Then 30-50ml/kg/hour
Do I correct dehydration first then acidosis, or simultaneously
Assess acidosis and fluid deficit separately and independently
Recommend correct dehydration first and then correct acidosis.
Contraindications to administering sodium bicarbonate and reason
Calves with severe respiratory disease
Additional CO2 generated may exacerbate hypercapnia (increase in CO2 in blood) and respiratory acidosis and decrease cerebrospinal fluid pH.
Which vein to give IV fluid in calf
Jugular
4 princples of oral fluid therapy
- Replacement of fluid to the circulating plasma volume and interstitium
- Provision of alkalinising agents to improve the buffering capacity of the blood.
- Increasing the strong ion difference by replacing lost sodium and potassium
- Maintaining blood glucose levels
Why Mixing electrolyte products with milk is not recommended
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 the abomasum
Two feeds should be separated by at least 1.5 hours
Indications to give antimicrobials
Systemic signs (pyrexia, decreased app, lethargy- Ecoli)
Blood/mucosa present
Suspect Salmonella or Ecoli
What kind of analgesia to provide scouring calves
NSAIDS
Analgesic/anti-inflammatory/anti-endotoxic agents
Meloxicam (0.5 mg/kg) – only one licenced
Only if correct dehydration
Other treatments- Cryptosporidium
Halofuginone (Halocur)
SID for 7 days, orally
not empty stomach
admin in oral fluids
Other treatments- Coccidiosis
Decoquinate (Decoxx)
Diclazuril (Vecoxan) tx and px lambs, aid control calves
Toltrazuril (Baycox) px clinical signs, reduced shedding
Sulphonamides
Vaccination of dams can help in what diseases
Rotavirus and Coronavirus
