Overview of calf d+ Flashcards
D+ epidemiology
- Infectious vs non-infectious
- Most agents ubiquitous/endemic
- Mixed infections are very common
- Zoonotic implications
- Dairy/suckler
- Housed/outdoors
Common pathogens in calf d+ (in descending order)
- Crypto sole agent
- Crypto co-infection
- Rotavirus sole agent
- Coccidia sole agent
- E.coli sole agent
- Coronavirus sole agent
- Co-infections not including Cryptosporidium
Which cause agents present as zoonosis?
- crypto
What influences the challenge of d+?
- Sources of infection
– Diseased animals
– Clinically normal carriers (often adults) - Pathogen “load”
– Hygiene/environment
– Stocking density
– Isolation of clinical cases
– Separation from adults
What influences the calf’s defences? (re calf dz/d+)
- Colostrum status
- Stress and stocking density
- Intercurrent disease (e.g. BVD, respiratory disease)
- Correct feeding
- Trace element status
Consequences of D+
- fluid loss
-> dehydration
–> pre-renal azotaemia
–> poorly perfused tissues -> lactic acid -> acidosis -> hyperkalaemia
loss of HCO3^- to GIT also contributes to acidosis
hypoglycaemia - due to increased time between feeding or because not eating as much
<5% dehydration CS in calves
- normal demeanour
- no eyeball recession
- <1s skin tent
6-8% dehydration CS in calves
- mild dehydration
- slightly depressed demeanour
- 2-4mm eyeball recession
- 1-2s skin tent
8-10% dehydration CS in calves
- moderate dehydration
- depressed demeanour
- 4-6mm eyeball recession
- 2-5s skin tent
10-12% dehydration CS in calves
- severe dehydration
- comatose
- 6-8mm eyeball recession
- 5-10s skin tent
> 12% dehydration CS in calves
- comatose/dead
- 8-12mm eyeball recession
- > 10s skin tent
CS of acidosis in calves
- Signs not very specific
- Poor/absent suck reflex
- Depressed/recumbent
- Comatose
- Increased respiratory rate
- Poor response to rehydration
- Common in calves >6d
– Especially beef suckler calves - Reduced or absent palpebral reflex
CS of Enterotoxigenic E. coli (ETEC) in calves
- Watery diarrhoea in young calf (<6d)
- Rapid progression to collapse (can get sick within 24h)
- Usually sporadic (single case)
- Some similarities with “watery mouth” in lambs
– Entry via GIT
– Bacteraemia
– Hygiene/colostrum important
– D+ less common in lambs
CS of Salmonellosis in calves
- Often bloody diarrhoea with pyrexia
- Can be pretty much any age
CS of Coccidiosis in calves
- Often less severe D+/systemic signs
- Sometimes darker, stiff faeces +/- blood
- Often tenesmus
- Usually peri-/post-weaning
- Only more severe if calf stops drinking etc
Tx of calf d+
- Most causes self-limiting
- Supportive therapy is usually the most important
- Correcting dehydration and acid-base balance
Oral tx
- quick
- easy
- farmer can perform
- but can be dangerous if the calf is very weak (e.g. can go into the lungs)
- recommended if less than 8% fluid deficit
IV tx
- safe if calf is very weak, collapsed
- more rapid effect
- can be more precise
- but more time-consuming/skilled
What major ion is lost in faeces and needs replacing in cases of d+?
- potassium
Should you continue milk feeding when giving oral electrolytes?
- yes
Should an oral electrolyte solution be acidic or alkalising?
- alkalising
Assuming a calf is showing signs of 5% dehydration, what is the most appropriate treatment protocol?
- 2 x 2L oral electrolyte feeds per day
Should electrolytes be added to milk replacer?
- no
What is the role of psyllium in electrolytes?
- thickens faeces
What is the role of glucose/proprionate in electrolyte solutions?
- for the sodium co-transporter
What else apart from fluids +/- antibiotics would be in your treatment plan?
- NSAIDs - meloxicam is licensed in calves?
Which calf to give antibiotics? 1 = recumbent, no suckle reflex, rr 62bpm, normal temp. 2 = standing, weak suckle reflex, pyrexic
- 1 -> YES: recumbent, looks rough, have to act quickly, this is a septic and dehydrated calf
- 2 -> NO: pyrexic but wouldn’t give AB as not septic
When treating with antibiotic, which antibiotic would you use? Which method of administration would you choose? Injectable?
- Injectable TMPS
- 3 first line farm ABs - TMPS, oxytet, amoxicillin
Calf pen size pre-weaning
- Want no less than 6m^3 per calf prior to weaning.
How long is the dry cow period?
- ~50-60d
Brix cut off for colostrum
- 22%
Serum total proteins cut off for PT measuring in calves
- 55mg/dL
TBC & E.coli colostrum cleanliness cut off
- TBC = 100,000 cfu/ml
- E.coli = 10,000 cfu/ml
Rainbow scour kit
- calf side kit
- useful and quick but not always accurate
- E.coli, crypto, rotavirus, coronavirus
Minimum time period for fully mucking out pens
- 4w
- bed up every day
- ensure using a good amount of straw
How to kill crypto
- steam clean - crypto needs over 60C
- resistant to bleach
- needs specific disinfectant
– hydrogen peroxide or specifically licensed products
– but often need 1-2h contact time, making it tricky for year round callers
Crypto tx
- Halifur
- Give in milk feeds but has v narrow therapeutic window
- If get it wrong will strip the abomasal lining
- Delays and reduces the amount of oocysts being shed but doesn’t stop it
- Need to give for 7 days.
