Energy Metabolism Flashcards
What do animals use energy for?
- Mechanical work
- Chemical work
- Synthesis of body components
Why is heat production a good way to measure energy loss?
All forms of energy are converted to heat
What is a calorie defined as?
heat required to raise 1 g of water from 16.5 to 17.5C
Why is the energy value of protein discounted from 5.6 Mcal/kg to 4 Mcal/kg?
It is not 100% digestible and many proteins are lost in urine.
What in a feed determines how much gross energy is in the feed?
carbon and hydrogen content
What are GE, DE, ME, and NE and how are they determined?
GE is total energy in the feed
GE - FE = DE
DE - UE = ME
ME - HI = NE
Why is GE not a good measure of energy available for an animal?
the animal does not use all of the energy for production or maintenance.
Are NE values of feeds for cattle the same as for pigs? Why or why not?
No because feeds are metabolized differently and they use different systems.
What is NEm, NEg, and NEI?
NEm measures maintenance
NEg measures tissue
NEl measures lactation
What is the purpose for partitioning energy in feed into NEm, Neg, and NEI?
- Determine how much to feed.
- What to feed and when
- How cattle will perform
- Precision
What 3 functions does an animal use NEm for?
- body temp regulation
- Essential metabolic processes
- Physical activity
What is heat increment?
It is the heat of digestion, digestive fermentation, absorption, and nutrient metabolism.
Basically the inefficiences in digestion
What are 4 methods to calculate heat production?
- Direct calorimetry (heat)
- Indirect Calorimetry (CO2)
- Blood flow and AV O2 differences
- Slaughter balance
What is metabolic body weight and why is it used?
The heat increment is proportional to body surface area. Big animals use energy more efficiencly.
What are 4 factors that affect efficiency of energy for growth and/or lactation?
- Environment
- Lactation and activity level
- Level of intake
- Genetic
