On farm nutrition monitoring

Question 1

list 2 diseases we are trying to avoid by managing nutrition on farm

Answer 1

ketosis an negative energy balance
hypocalcaemia (milk fever)

Question 2

when are cows at risk of NEB

Answer 2

straight after calving
peak lactation- especially in very high yielding cows

Question 3

List 4 impacts Negative energy balance/ ketosis have on cows

Answer 3

reduced milk quality
decreased fertility
impaired immune function
role in other diseases

Question 4

how does NEB reduce fertility

Answer 4

reduce follicular wave
reduction in LH surges
more prone to ovarian cysts

Question 5

how can NEB increase likelihood of LDA

Answer 5

ketones can impair appetite
cow doesn’t fill rumen as much
more likely to cause LDA

Question 6

how do you want BCS to change over the dry period

Answer 6

no change

Question 7

what target change of BCS do we want between calving and peak lactation

Answer 7

Max decrease of 0.5

Question 8

what BCS do we want dairy cows at calving

Answer 8

2.5-3
avoid >3

Question 8

when should you measure BHB

Answer 8

very useful in fresh calvers

Question 9

when is measuring NEFAs most useful

Answer 9

useful for transition - especially dry

Question 10

Why is looking at NEFAs useful

Answer 10

are a transport form of fat
indicator of fat mobilisation

Question 11

How many samples should you take when looking into metabolic profiles of herd

Answer 11

8-12 samples/ group

Question 12

what is the target prevalence of high BHB or NEFA

Answer 12

<10-20%

Question 13

what can you look at for indicators of energy levels in milk

Answer 13

decreased protein= decreased energy

Question 14

how can you improve butter fat levels in milk

Answer 14

increase fibre in diet

Question 15

how do you analyse a cow ration

Answer 15

look at feed fence
assess feed intake
calculate ration energy density
compare to cow requirements

Question 16

what is DMI

Answer 16

dry matter intake
kg fed per head – kg leftover refusals per head

Question 17

if there is a NEB problem in transition/ calving what could be the problem

Answer 17

poor dry matter intake
excess BCS/ overfeeding

Question 18

if there is NEB problem in early/ peak lactation what could be the problem

Answer 18

poor dry matter intake
low ration energy density

Question 19

what is the target DMI for high yielding cow

Answer 19

> 23kg/d

Question 20

what is the target DMI for transition (late dry period)

Answer 20

> 12kg/d

Question 21

List 5 ways to improve dry matter intake

Answer 21

easy access, trough space per cow
maximise ration palatability
minimise group changes
avoid over-conditioned cows (especially at calving)
manage environment appropriately

Question 22

what is a rule about moving cow groups

Answer 22

move if under 3 days
or after 3 weeks
to do with time to take to form hierarchy

Question 23

When is there a natural drop in DMI - how do you try to manage this

Answer 23

at calving
minimise the fall
maximise the rate of increase after calving

Question 23

list 3 reasons why ration formaulation may go wrong

Answer 23

Something “wrong” with calculated ration?
Not being mixed or fed correctly?- over mixed/ chopped
An element of the diet has changed- e.g. silage quality changes

Question 24

why can over chopping feed be a problem

Answer 24

reduces the scratch factor of the feed –> reduced rumen turnover –> reduced cudding , therefore less energy from it

Question 25

Why can’t we just increase the diet energy density in cows

Answer 25

energy densities of ingredients don’t vary all that much
Need to avoid overfeeding starchy feeds to keep rumen healthy

Question 26

what does monensin do

Answer 26

Antibiotic, changes rumen flora to aid energy balance - bolus for “at risk” cows

Question 27

list the at risk animals for ketosis

Answer 27

older
fat
cows that have had long dry period

Question 28

What effects does hypocalcaemia have on smooth muscle

Answer 28

subclinical effects
uterus- reduced contraction (involution) –> increase chance of uterine infection
GI tract- reduction in DMI and increase in abomasal disease

Question 29

Target incidence rate of milk fever

Answer 29

<5% per year

Question 30

Describe how low DCAB reduces milk fever

Answer 30

induces mild metabolic acidosis this means…..

enhanced uptake of Ca from the GI tract
Ca mobilisation from bone
higher rate of vitamin D3 activation per unit PTH
increased target tissue sensitivity to PTH and activated vit D3

Question 31

Describe a ‘true’ DCAB diet

Answer 31

Aim for diet DCAB around -100 mEq/kg DM
likely requires use of anionic salts
needs Ca supplementation

Question 32

List 3 disadvantages of ‘true’ DCAB

Answer 32

reduced palatability
expensive
needs a lot of monitoring

Question 33

describe a ‘partial’ DCAB diet

Answer 33

Aim for diet DCAB around 0 to -50 mEq/kg DM
Often just by choosing lower DCAB feeds, may also use salts
Usually doesn’t require Ca supplementation
More common in lower yielding herds

Question 34

list 2 feeds that can be added to silage to reduce DCAB

Answer 34

brewers grains
rape extract

Question 35

why do some farmers add Mg to dry diet to reduce milk fever

Answer 35

Mg required for production of PTH
Generally not very effective alone