Week 8: Energy Systems

Question 1

How can we calculate energy?

Answer 1

• In vitro method
• Forumlas
• Feeding table

Question 2

What do we require when formulating diets?

Answer 2

Knowing the energy content of the feed and the energy requirements of the animal

Question 3

What do animals tend to show?

Answer 3

A continous respone to increasing energy

Question 4

For feeds, most work on what?

Answer 4

ME not NE

Question 5

For requirements, most work on what?

Answer 5

NE (different efficiencies for each process)

Question 6

What are two early energy systems?

Answer 6

Armsby’s net energy system and Kellner’s starch equivilants

Question 7

What is Total Digestible Nutrients (TDN)?

Answer 7

Total digestible crude protein and digestible carbohydrate (crude fibre and N-free extracts) plus 2.25 x digestible fat

Question 8

UK ag research council ME system …?

Answer 8

Provides estimates of energy requirements of growing, lactating and pregnant sheep and cattle
Food energy expressed as ME
Animal energy requirements expressed as NE
Uses a series of equations to predict efficiency of ME used for maintenance, growth, preg, lactation

Question 9

How do you predict animal performance?

Answer 9

• Calculate metabolisability (qm) of feed

- Calculate k values

Question 10

How do you calculate metabolisability?

Answer 10

qm

ME of feed divided by GE of feed (as a proportion)
EG:

11. MJ ME/kg DM (GE = 18.4 MJ/kg DM) = 0.6

Question 11

What is basal metabolism?

Answer 11

Energy expended at rest.
Energy expended (heat) for a fasting animal with no activity