Negative Energy Balance Flashcards
what are the diseases that occur around the transition period
what is the transition period
sudden increase in nutrition for milk production
100-120MJ to 300MJ or more
what occurs in the early lactation
physiological negative energy balance (NEB)
what occurs to DMI in the last week of pregnancy
decreases
what is more pronounced in fat cows during the last week of pregnancy
decrease in DMI
what are the risks and results of the tranistion period
what are the volatile fatty acids
acetate
propionate
butyrate
what are the typical VFA ratios
acetate: propionate:butyrate
70: 20:10 for high forage diets
60: 30:10 for high starch diets
what % of energy do VFAs provide
60-80%
describe normal energy metabolism in the ruminant
what occurs to normal energy balance during ketosis
energy comes from the catabolism of fat deposits which produce free fatty acids (NEFAs) which are converted into acetyl CoA which can enter the krebs cycle and glucose is produced
once too many NEFAs are produced they cannot enter the krebs cycle because it is overwhelmed and they are converted into ketone bodies
what are the ketone bodies
Acetone
Acetoacetate
B-hydroxybutyrate
what occurs during fatty liver
Fatty liver occurs when the rate of FA esterification to triglycerides (TGs) exceeds the rate of disappearance by hydrolysis and export as a constituent of VLDL
Considered to occur when liver TG > 30 mg/g wet
Ketosis and fatty liver can be thought of as different manifestations of the same disease
Subclinical can shift to clinical by small changes such as increasing dietary protein content
what is the epidemiology of ketosis
common
1-50% incidence
high producing, older dairy cows
what is the etiology of ketosis and the difference between primary and secondary ketosis
Over condition dry cows (‘fat cow syndrome’)
Primary ketosis:
- Pathophysiological in high yielding dairy cows
- Poor dry cow management
- Poor fresh cow management
Secondary ketosis:
- Retained fetal membrane, metritis
- Hypocalcemia
what are the clinical signs of ketosis
Inappetance or anorexia — often roughage only
Milk drop and rapid weigh loss
Feces +/- firm and dry
Depression
Reduced rumen contraction frequency and strength
Temperature, cardiovascular, respiratory all normal
+/- acetone on breath
what are the clinical signs of nervous form of ketosis
Very rare
Delirium
Circling
Leaning and crossing legs
Licking and chewing manias
Blindness
what are the clinical findings of ketosis
Many cows systemically okay
Main effect:
- Milk production
- On reproductive performances
- Submission rate
- Conception rate
how is ketosis diagnosed
Individual or herd
History — signalment
Clinical exam
Lab
Biochemistry
what biochemistry measurements can diagnose ketosis
ketone bodies (blood, urine, milk)
NEFA (blood)
glucose (blood)
what are the big variations on ketone bodies
feeding time
moment of days
milking time
what are the normal levels of ketone bodies (BHB) in the blood
- 4 mmol/L (fresh cows)
- 7 mmol/L (dry cows)
what are the normal levels of NEFAs in blood
300 umol/L (dry cows)
600 umol/L (fresh cows)
what are the normal glucose levels
30-40 mg/100ml or 3.0 mmol/L
Not as straight forward as ketone bodies and less practical
how is fatty liver diagnosed
clinical signs
liver biopsy
liver enzymes
post mortem
how is ketosis treated
Hypoglycemia — glucose/dextrose IV (500ml of 50%)
Oral glucogenic agents — propylene glycol (glycerol, propionate salts)
Stimulate gluconeogenesis: steroids!
Choline and vitamin B
Vit E and Se
No Calcium IV
- Damage hepatic tissue
how is glucose/dextrose IV used to treat ketosis
500ml of 50%
Large proportion excreted in urine
2-3x a day
Reduced insulin response to glucose in ketotic cows
Essential in cases showing nervous signs
Additional treatment needed to prevent relapse
how is oral glucogenic agents such as propylene glycol used to treat ketosis
Most common treatment on farm usually
250ml drench 2-3x day, then decrease
Farmer can do it
Pre-made drench for fresh cows
Converted in pyruvate, then OAA
Elevated blood glucose in 4h
If too much, decreases appetite
- Counterproductive effect
May accumulate causing somnolence (drowsy)
how are steroids used to treat ketosis
In ruminants probably change glucose distribution and utilization rather than stimulating gluconeogenesis
Hyperglycaemic agents (increase glucose in 24h)
Reduce milk yield
Not necessarily what the farmer wants
Short course not to decrease milk yield too much
Increase lipolysis
Increase hepatic triglyceride secretion
ex. Dexamethasone 1.33 mg/45 kg (25ml)
With other diseases?
- Immunosuppression
how can choline and vitamin B be used to treat ketosis
hepatoprotectors
free TGs from liver
how are vit E and Se used to treat ketosis
anti-oxidant
protection muscle damage due to auto-peroxidase
how is ketosis prevented
Everything possible should be done to maximize dry matter intake and reduce stress
- Minimum competition — no overcrowding
- 0.8m x cow: 80% feeding space
- 12m^2 lying space (80% cubicle space)
- May warranty a separate management group (cows vs heifers)
- Hygiene
- Maximize cow comfort
- No pathological conditions (lameness)
- Perfect nutrition!
what nutrition should be fed with dry and post partum rations to maximize DMI in the transition period
High palatable forages
Consistent delivery of the diet:
- Same one
- Same time
- Well mixed (no sorting)
- Fibre chopped to max 2.5-3cm
Ensure palatable feed and water available at all times (24h)
10% left over the next day
Adequate levels of micro-elements
what are the conventional dry cow nutrition groups
Far off dry group (40d) — low energy diet
Close up dry group (20d)
- Similar ration to milking cows
- For ruminal adaptation
- High energy density
- Introduce rapidly fermentable CHO and concentrate
what is a new ‘golddilocks’ dry cow nutrition management
Far off and close up: both low energy diet
High content of straw and fibre (100-120MJ)
Force the cows to eat as much as they can
Full rumen
No BCS gain or loss
Essential good management
what is the optimal BCS to prevent ketosis
2.75-3.25
dry off: 3-3.25
calving: 3.25
no loss or gain during the dry period
right BCS entering the dry period –> good fertility
how can monensin be used to prevent ketosis
Increase propionate-producing bacteria
Better repartition of energy
In the close up and PP ration (transition period)
Kexxton bolus
In EU on vet prescription
how can you monitor for ketosis
Ketone bodies (post partum)
- Over 1.4mmol/L or purple
NEFA (pre-partum)
- Over 300umol/L
Milk solids
- Protein/fat ratio .075
- Fat over 5.5
- Protein less 3
Transition cow disease
- Ketosis
- Metritis
- RFM
- DA
BCS changes — dynamic
Dry matter intake
