LA Metabolic Dx 1 - Energy Flashcards
ME Requirements
Maintenance
Cow size = 1MJ/10kg
Diet quality
ME Requirements
Lactation
5MJ
Total yield
Milk composition
Diet quality
ME Requirements
Pregnancy
25wks = 5MJ
30wks = 10MJ
35wks = 20MJ
40wks = 45MJ
Example Q - ME requirements for non-pregnant, 650kg dairy cow, yielding 50L milk/d
BW = 65MJ
50x5 = 250MJ
250MJ + 65MJ = 315MJ
Example Q Part 2 - Grass silage has DM content of 30% and ME of 10MJ/kg DM. How many KG of fresh weight would cow need to eat to meet required energy?
315 from part 1
315/10 = 31.5MJ = 30%
31.5/30 x100 = 105kg = 100%
Negative Energy Balance Risk Factors
4 points
Milk yield
- Breed
- Feeding system
- Management system
DMI
- Increase BCS
- Poor transition management
- Poor feed access
Ration Prep
- Poor quality ingredients
- Inadequate prep
- Incomplete mix
Ration Formula
- Poor energy density
- Lack FME
- FME:ERDP ratio
-ve Energy Balance - Clinical Conditions
- Ketosis = cattle
- Pregnancy toxaemia = sheep*
- Fatty liver
- Abomasal displacements
-ve Energy Balance - Subclinical Conditions
- Ketosis/ fatty liver
- Immunosuppression
- Poor repro performance
Ketosis - Aetiology
- Brain, foetus and udder = ++glucose
- 50% from diet
- 50% from TCA cycle (propionate)
- Not enough propionate = no glucose
- Acetate and butyrate -> acetyl coA -> ketones -> blood and milk
Ketosis - Peripheral Insulin Resistance
High BCS +/- excess ME in early DP ->
- ↓ tissue response to insulin→
- ↓ glucose uptake
- ↓ Satiety →↓ DMI
Type 1 Ketosis
Energy intake < output
Peak lactation
Highest energy demand
Increase BHB
~20-60DIM
Type 2 Ketosis
Insulin resistance
Fat -> liver
Around calving
Not just fat cows
Diet/ intake in late dry period **
<20DIM
Increase NEFA
Nervous Ketosis - Signs
Excitable, altered behaviour +/- aggression
Muscle fasciculations
Compulsive licking / pica
+/- Incoord, circling & head pressing
+/- Collapse, seizures & death
Clinical Ketosis - Signs
Serum BHB >1-1.4
↓ Milk yield
↓ Body Condition Score
↓ DMI, selective appetite & poor
rumen fill
Acetone smell on breath
Ketosis Management
Oral glucose precursors
= Propylene glycol
= Glycerol
Glucocorticoids
= Appetite stim
= Promote gluconeogenesis
B Vitamins
= Appetite stim
IV dextrose - only nervous ketosis
Nutrition & nursing
Choline bolus - produce VLDLP - reduce fatty liver
Ketosis Subclinical Signs
Immunosuppression
- ↑ incidence / severity of
periparturient infectious dx
- Uterine inflammatory disease
(e.g. metritis)
- Mastitis
Poor repro performance
- Poor pregnancy / conception
- Poor oestrus expression
↓ or variable BCS
Milk constituents
- ↓ milk protein
- ↑ milk butterfat and/or
fat:protein ratios
Fatty Liver - Aetiology and Risk Factors
-ve Energy Balance -> mobilise body fat
Increase BCS →
- Lower DMI→ increase NEBAL
- More fat mobilisation
- Peripheral IR
+/- Overfeeding in dry period
Fat deposit in liver:
- Lack of Acetyl CoA → free fatty
acid unable to enter the TCA
cycle
- Depleted lipoproteins → liver
unable to export fat
Impaired liver function
Fatty Liver - Clinical Signs
Obesity -> rapid weight loss
Anorexia & depression
↓ milk yield
Rumen hypomotility
+/- signs of liver dysfunction (rare)
- Icterus
- Hepatic encephalopathy
+/- death
Poor prognosis
Pregnancy Toxaemia - Aetiology and Risk Factors
Energy Demand
- Multiple pregnancies
- ‘Twin lamb dx’
- Inclement weather
DMI
- Decrease BCS
- Poor feed access
- Poor dentition
Ration Prep
- Inadequate/absent
supplement feed
- Poor quality forage
Pregnancy Toxaemia - Clinical Signs
↓ appetite/ anorexia
Dullness & depression
Isolate from the flock
Muscle fasciculations
BCS loss
+/- Collapse & recumbency
+/- Bilateral central blindness / ‘Star gazing’
Concurrent hypocalcaemia & fatty liver is common
Pregnancy Toxaemia - Diagnosis and Management
Diagnosis = signs, BHB >3
Management
- Oral glucose precursors
- IV dextrose
- NSAIDS
- Tx hypocalcaemia
- Induce parturition
- Glucocorticoids & PGF
- C-section
- Euthanasia
