Metabolic disease in ruminants

Question 1

What can cause post natal depression in the dairy cow?

Answer 1

• Milk fever.
• RFM / Metritis / Endometritis.
• Mastitis.
• Displaced abomasum.
• Ketosis.
• Fertility.
• Lameness.

Question 2

What is homeostatic control of Ca2+?

Answer 2

• Parathyroid Hormone PTH
  – mobilisation of Ca2+ from bone “stores”
  – increased absorption from gut (Requires Mg2+ to function)
• Calcitonin – reduces Ca2+ absorption and availability
• Vitamin D3 – increased absorption from gut
• blood Ca2+ in two forms (50:50 – 60:40):
  – Bound (chiefly to albumin)
  – Ionised - Ca2+ - active
  – pH dependant – reduced binding with reduced blood pH

Question 3

What is the role of Ca2+ in the body?

Answer 3

• Muscle function**
• Nerve impulses
• Immune response

Question 4

What is seen with acute milk fever?

Answer 4

• At/after calving =
• Initial hyper excitation – tremor etc
• RECUMBENT – muscles stop working
• Guts/glands etc stop working
• No faeces
• No urination
• Dry noses
• Postural bloat
• SLOW PULSE/HEART-RATE
• can be complicated by concurrent hypomag. and/or, hypophos

Question 5

What are Ddx for a recumbent cow?

Answer 5

• Milk fever - no faeces, normal/low temp
• Acute coliform mastitis - high pulse + HR, endotoxaemic
• Botulism
• Other acute diseases - salmonella
• Injury at calving - nerve damage (femoral + obturator), femoral head (ligament trauma)

Question 6

How can you treat downer cows?

Answer 6

• Milk fever - respond to Ca alone
• MF + hypophosphataemia = Ca + Phos
• Trauma / nerve damage = poor prognosis

Question 7

What is hypocalcaemia a risk factor for?

Answer 7

• Immune function depressed
• Coliform mastitis
• Metritis / endometritis
• Post partum depression

Question 8

How can you prevent hypocalcaemia?

Answer 8

• Feed low Ca diet pre-calving
• Feed high magnesium pre-calving
• Boluses / drench / stomach tube at calving
• Maximise DMI pre-calving

Question 9

When do you get hypocalcaemia in sheep?

Answer 9

• NOT after lambing
• Pre lambing = stress = movement back from tack, bad weather, inadequate feed barrier space

Question 10

What is grass staggers? How does it occur?

Answer 10

• Hypomagnaesemia - no body stores of Mg
• Output = milk, higher than input (diet)
• High K+ reduces Mg absorption = lush grass, fertilisers

Question 11

What are clinical signs of hypomagnesaemia?

Answer 11

• Peracute / acute = sudden death
• Early = twitchy + hypersensitive
• Recumbent + convulsive (emergency)

Question 12

What animals are predisposed to hypomagnesaemia?

Answer 12

• Stress = weather, movement, handling
• Spring = dairy cows + twin bearing ewes
• Autumn = suckler cows with large calf at foot

Question 13

How would you treat hypomagnesaemia?

Answer 13

• Control convulsions = xylazine, pentobarbitone
• Give Ca 40% IV
• Slowly give up to 200ml MgSO4 IV
• If not recumbent = bottle of MgSO4 SC

Question 14

How can you prevent hypomagnesaemia?

Answer 14

• Move off affected pasture
• Give additional Mg =
• Dairy cows - high Mag cake
• Beef cows - mineral supplements, Mag blouses, wean calves, give straw (slow gut transit time)

Question 15

What is fat mobilisation syndrome + ketosis?

Answer 15

• Energy deficit - NEB
• Excessive mobilisation of fat for energy
• ‘all cows develop NEB but not all develop ketosis/FMS’

Question 16

What are signs of clinical ketosis?

Answer 16

• Reduced milk yield
• Selective appetite - refuses concentrates
• Ketone bodies in blood - smell
• Firm faeces - shiny
• Nervous ketosis

Question 17

How is ketosis treated?

Answer 17

• Propylene glycol - toxicity
• Corticosteroids
• Glucose IV
• Vitamin B12
• Thiamine B1
• Kexxtone bolus

Question 18

What is a kexxtone bolus? What does it do?

Answer 18

• Monesin
• inhibit growth of gram +ve bacteria which produce most of the acetate, lactate + hydrogen in the rumen increasing propionate + glucose production

Question 19

What is nervous ketosis? Ddx? Tx?

Answer 19

• hyper excited
• Twitchy
• Maniacal licking, salivation
• Dangerous
• Ddx = Hypomagnesaemia, listeriosis, BSE
• Glucose IV

Question 20

When do cows get sub clinical ketosis? How is it diagnosed?

Answer 20

• Early lactation
• beta-hydroxybuturate of >1mmol/L

Question 21

What would you observe to monitor nutritional status?

Answer 21

• BCS changes
• DMI
• Cudding
• Rumen fill
• Faeces
• Cleanliness
• Lying time

Question 22

What can be measure to check for energy?

Answer 22

• BHOB
• Glucose
• NEFA

Question 23

What can be measured to check for protein?

Answer 23

• Urea
• TP
• Albumin
• Globulin

Question 24

How can rumen function be examined?

Answer 24

• Faecal sieving - mucus, fibre length, grain processing
• Rumen pH + protozoa assessment - rumenocentesis, oral sampling devices
• pH measuring boluses

Question 25

How can Fat mobilisation syndrome / ketosis be prevented?

Answer 25

• Feeding in dry period
  – LOW ENERGY (M/D 8.5 – 9.0)
  – Maximise DMI in dry cows =
• Comfort (luxury)
• Palatable diet
• Food at all times
• Monitor CS
• Avoid fat cows