Overview of calf d+

Question 1

D+ epidemiology

Answer 1

• Infectious vs non-infectious
• Most agents ubiquitous/endemic
• Mixed infections are very common
• Zoonotic implications
• Dairy/suckler
• Housed/outdoors

Question 2

Common pathogens in calf d+ (in descending order)

Answer 2

• Crypto sole agent
• Crypto co-infection
• Rotavirus sole agent
• Coccidia sole agent
• E.coli sole agent
• Coronavirus sole agent
• Co-infections not including Cryptosporidium

Question 3

Which cause agents present as zoonosis?

Answer 3

• crypto

Question 4

What influences the challenge of d+?

Answer 4

• Sources of infection
  – Diseased animals
  – Clinically normal carriers (often adults)
• Pathogen “load”
  – Hygiene/environment
  – Stocking density
  – Isolation of clinical cases
  – Separation from adults

Question 5

What influences the calf’s defences? (re calf dz/d+)

Answer 5

• Colostrum status
• Stress and stocking density
• Intercurrent disease (e.g. BVD, respiratory disease)
• Correct feeding
• Trace element status

Question 6

Consequences of D+

Answer 6

• 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

Question 7

<5% dehydration CS in calves

Answer 7

• normal demeanour
• no eyeball recession
• <1s skin tent

Question 8

6-8% dehydration CS in calves

Answer 8

• mild dehydration
• slightly depressed demeanour
• 2-4mm eyeball recession
• 1-2s skin tent

Question 9

8-10% dehydration CS in calves

Answer 9

• moderate dehydration
• depressed demeanour
• 4-6mm eyeball recession
• 2-5s skin tent

Question 10

10-12% dehydration CS in calves

Answer 10

• severe dehydration
• comatose
• 6-8mm eyeball recession
• 5-10s skin tent

Question 11

> 12% dehydration CS in calves

Answer 11

• comatose/dead
• 8-12mm eyeball recession
• > 10s skin tent

Question 12

CS of acidosis in calves

Answer 12

• 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

Question 13

CS of Enterotoxigenic E. coli (ETEC) in calves

Answer 13

• 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

Question 14

CS of Salmonellosis in calves

Answer 14

• Often bloody diarrhoea with pyrexia
• Can be pretty much any age

Question 15

CS of Coccidiosis in calves

Answer 15

• 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

Question 16

Tx of calf d+

Answer 16

• Most causes self-limiting
• Supportive therapy is usually the most important
• Correcting dehydration and acid-base balance

Question 17

Oral tx

Answer 17

• 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

Question 18

IV tx

Answer 18

• safe if calf is very weak, collapsed
• more rapid effect
• can be more precise
• but more time-consuming/skilled

Question 19

What major ion is lost in faeces and needs replacing in cases of d+?

Answer 19

• potassium

Question 20

Should you continue milk feeding when giving oral electrolytes?

Answer 20

• yes

Question 21

Should an oral electrolyte solution be acidic or alkalising?

Answer 21

• alkalising

Question 22

Assuming a calf is showing signs of 5% dehydration, what is the most appropriate treatment protocol?

Answer 22

• 2 x 2L oral electrolyte feeds per day

Question 23

Should electrolytes be added to milk replacer?

Answer 23

• no

Question 24

What is the role of psyllium in electrolytes?

Answer 24

• thickens faeces

Question 25

What is the role of glucose/proprionate in electrolyte solutions?

Answer 25

• for the sodium co-transporter

Question 26

What else apart from fluids +/- antibiotics would be in your treatment plan?

Answer 26

• NSAIDs - meloxicam is licensed in calves?

Question 27

Which calf to give antibiotics? 1 = recumbent, no suckle reflex, rr 62bpm, normal temp. 2 = standing, weak suckle reflex, pyrexic

Answer 27

• 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

Question 28

When treating with antibiotic, which antibiotic would you use? Which method of administration would you choose? Injectable?

Answer 28

• Injectable TMPS
• 3 first line farm ABs - TMPS, oxytet, amoxicillin

Question 29

Calf pen size pre-weaning

Answer 29

• Want no less than 6m^3 per calf prior to weaning.

Question 30

How long is the dry cow period?

Answer 30

• ~50-60d

Question 31

Brix cut off for colostrum

Answer 31

• 22%

Question 32

Serum total proteins cut off for PT measuring in calves

Answer 32

• 55mg/dL

Question 33

TBC & E.coli colostrum cleanliness cut off

Answer 33

• TBC = 100,000 cfu/ml
• E.coli = 10,000 cfu/ml

Question 34

Rainbow scour kit

Answer 34

• calf side kit
• useful and quick but not always accurate
• E.coli, crypto, rotavirus, coronavirus

Question 35

Minimum time period for fully mucking out pens

Answer 35

• 4w
• bed up every day
• ensure using a good amount of straw

Question 36

How to kill crypto

Answer 36

• 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

Question 37

Crypto tx

Answer 37

• 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.