Chapter 9.2- Energetics (Nov 24)

Question 1

give 2 examples of behavioral acclimatization

Answer 1

1. penguins huddling (minimizes SA exposed to wind etc)

2. geese standing on ice: switch standing on 1 foot, warming the other

Question 2

give an example of physiological acclimatization

Answer 2

geese standing on ice: warm arterial blood warms up blood in veins that has been cooled from the ice outside

Question 3

animals get ___(more/less) energetically efficient as they get older

Answer 3

less

Question 4

efficiency of __ deposition is greater than ___

why

Answer 4

muscle
fat

muscle is 75% water, 20% protein –> water is easy to deposit and readily available

Question 5

why is deposition of fat less efficient?

Answer 5

1.4g fat replaces 0.4g water –> so 1.4g fat deposition= 1g body weight gain

Question 6

young animals deposit primarily ___, older animals (approaching sexual maturity) deposit primarily ___

Answer 6

muscle

fat when older

Question 7

why does fat deposition increase as age and body weight increase?

Answer 7

• energy content of liveweight gain increases

- more net energy needed per kg of liveweight gain

Question 8

why is more energy required as animals get larger?

Answer 8

larger body to maintain before any energy can be used for growth/ work

Question 9

when would you market a growing animal?

Answer 9

when it starts to lose efficiency (amount of feed to body weight gain)

Question 10

with adequate protein and insufficient energy:

Answer 10

amino acids are deaminated and C-skeletons are used for energy

Question 11

as energy retention increases, ___ retention increases until __ becomes ____

or until

Answer 11

protein

proteins, limiting

or until max protein synthesis is reached (animals continue to deposit fat)

Question 12

what’s the rationale behind rapid growth?

Answer 12

more rapid growth= fewer days of maintenance costs to reach a particular body weight

Question 13

compensatory growth=

Answer 13

moderate restriction of growth rate for a portion of the growth curve to encourage more efficient growth at a later stage of the growth curve

Question 14

goals of compensatory growth

Answer 14

achieve the same final body weight at the same age, but for cheaper

Question 15

Explain the following theory that is used for compensatory growth:

Set-point for body size vs age

Answer 15

animal physiologically “knows” what body weight they should be at a particular age
- controlled by CNS

Question 16

Explain the following theory that is used for compensatory growth:

peripheral control

Answer 16

• regulated by cell number

- early restriction can reduce cell # (must time it right for compensatory growth)

Question 17

if feed restriction is done too early, cell ____ is reduced

Answer 17

NUMBER

= permanent stunting

Question 18

if feed restriction is done too late, cell ___ is reduced

Answer 18

size

can return to normal state after refeeding

Question 19

3 ways to accomplish compensatory growth:

Answer 19

• limit amount of feed
• limit quality of feed
• limit duration of feeding