Basic nutrition

Question 1

What is metabolisable energy (ME)?

Answer 1

Energy available for maintenance, growth, lactation and pregnancy
(Assumes a healthy rumen and microflora)

Question 2

Where are volatile fatty acids absorbed?

Answer 2

Across rumen wall

Health of papillae essential

Question 3

Where are fats and oils absorbed?

Answer 3

Small intestine

Question 4

Why does body weight drop as milk yield increases?

Answer 4

Cows don’t eat enough to meet energy requirements for how much they need for peak lactation
NEGATIVE ENERGY BALANCE
Mobilise body fat to provide energy
(Normal mechanism - target loss 0.5-1BCS)

Question 5

How much maintenance energy (ME) does a dairy cow typically require per day?

Answer 5

65-70 MJ

+5MJ/litre milk

Question 6

Which stage of bovine pregnancy requires an increase in maintenance energy requirements?

Answer 6

Late pregnancy (last few weeks)

Question 7

Protein is metabolised in the rumen into what? (2)

Answer 7

Rumen degradable protein
(RDP - any nitrogen containing compound)
Rumen undegradable protein (RUP)

Question 8

What are rumen degradable proteins broken down into?

Answer 8

NH4+ (ammonium ions)

Question 9

Where is microbial protein digested?

Answer 9

Abomasum

Question 10

High blood or milk urea suggests what about a cattle’s nutrition?

Answer 10

Insufficient maintenance energy

Excess effective rumen degradable protein (ERDP)

Question 11

Where is rumen undergradable protein (RUDP) digested?

Answer 11

Abomasum

Small intesine

Question 12

How much protein does a dairy cow require?

Answer 12

16% if yield <8000L

18% if yield >8000L

Question 13

Give examples of how DMI be maximised in lactating cows

Answer 13

Maximise DMI intake in dry period - essential!
Palatable diet
Comfortable environment to eat
Avoid subacute rumenal acidosis (SARA) - change diets slowly over 3 wks
Good health - e.g. lameness

Question 14

What % of bodyweight should DMI intake aim to be at peak yield?

Answer 14

4% BW

Question 15

How many litres capacity is the rumen?

Answer 15

200+ litres

Question 16

What is between the digest and gas space of rumen?

Answer 16

Fibre mat

Where bugs located, traps foods

Question 17

The secondary cycle of rumen contractions includes what contraction?

Answer 17

Dorsal rumen contraction

Primary cycle = all other contractions

Question 18

How much of their BW does a ruminant eat per day?

Answer 18

2% - standard
More if lactating (3% for 30L, 4% for 40l)
Less if heavily pregnant (calf reduces abdo space)

Question 19

How is DMI intake affected by a cow being overweight?

Answer 19

DMI intake increased

‘Fat cows eat less’

Question 20

How much DMI (kg) should a dry cow have per day?

Answer 20

12-14kg