Flashcards in Feed analyses 2 Deck (13):
Define 'gross energy'
Measure of heat of combustion of feed via bomb calorimeter
Most feeds GE ~ 18MJ/kgDM
Define 'digestible energy'
GE of feed - GE of faeces
Define 'metabolisable energy'
GE of feed - (GE faeces + GE urine + GE gas)
ie GE of feed - waste products
Define 'net energy'
ME - heat increment (energy stored by animal)
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)
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
Describe process of indirect calorimetry
Resp. quotient (RQ)
Protein oxidised estimate via urinary nitrogen
What is the 'respiratory quotient'? What does it calculate?
Ratio of CO2 produced & O2 consumed - calculates fat & CHO oxidised
Technique for measuring non-structural carbohydrates (NSC)?
Sugars - colorimetrically after digestion
Starch - after hydrolysis & polarimetric analysis
Technique(s) for measuring minerals?
Atomic absorption spectroscopy
Flame emission spectroscopy
Technique for measuring AAs, FAs, vitamins?
Chromatographic separation after proteins, fats hydrolysed or extracted
What is ADIN?
Acid-detergent insoluble nitrogen - measures unavailable nitrogen of animals