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Flashcards in Feed analyses 2 Deck (13):
1

Define 'gross energy'

Measure of heat of combustion of feed via bomb calorimeter
Most feeds GE ~ 18MJ/kgDM

2

Define 'digestible energy'

GE of feed - GE of faeces

3

Define 'metabolisable energy'

GE of feed - (GE faeces + GE urine + GE gas)
ie GE of feed - waste products

4

Define 'net energy'

ME - heat increment (energy stored by animal)

5

Define 'heat increment'

Energy lost as heat (general metabolism of cell maintenance/growth/prod. (main) & microbial fermentation) measured by calorimeter (directly) or resp. exchange (indirectly)

6

Describe process of direct calorimetry

Airtight, insulated container - evaporative losses measured as change in air moisture & sensible heat loss thru wall
Heat production measured at 2 levels of intake

7

Describe process of indirect calorimetry

Resp. exchange
Resp. quotient (RQ)
Protein oxidised estimate via urinary nitrogen
Brouwer equation

8

What is the 'respiratory quotient'? What does it calculate?

Ratio of CO2 produced & O2 consumed - calculates fat & CHO oxidised

9

Technique for measuring non-structural carbohydrates (NSC)?

Sugars - colorimetrically after digestion
Starch - after hydrolysis & polarimetric analysis

10

Technique(s) for measuring minerals?

Atomic absorption spectroscopy
Flame emission spectroscopy

11

Technique for measuring AAs, FAs, vitamins?

Chromatographic separation after proteins, fats hydrolysed or extracted

12

What is ADIN?

Acid-detergent insoluble nitrogen - measures unavailable nitrogen of animals

13

What is NIRS?

Near Infrared Reflectance Spectroscopy - measures feed parameters
Requires large calibration set for known data
Fast, cheap, non-destructive