Digestibility Flashcards
Digestibility
the amount of nutrients and/or energy that is unaccounted for in the feces or ileal digesta
-the rate of disappearance of dietary nutrients and/or energy in the GI tract of an animal/bird
Digestibility Formula
[(intake - output)/intake] x 100
Factors affecting digestibility
-species-
-age of the anima
-physical nature of the feed
-level of intake
-chemical nature of feed
Chemical nature of feed
-crude fiber content
-crude protein content
-minerals
-vitamins
-fats-
-antibiotics
-enzymes
Factors affecting nutrient requirements
-stage of growth
-size of animal
-environment
-heredity
-disease
-activity
-condition of animal-
-species of animal
Gross performance evaluations
-group feeding or feedlot trials
-individual feeding
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Group feeding or feedlot trials pros and cons
pros: quick, easy, and very practical
cons: loss of precision, costly, needs space, no info on intermediate processes in digestion
Digestibility/Balance studies
pros: more exact information about intermediate processes and fewer animals required
cons: intensive labor and subject to individual variation
DIgestion trials
-the diet is mixed and sample analyzed for the nutrients under study
-a constant amount of the diet fed daily
-feces are collected, weighed, and analyzed for the nutrients being studied and then related to a known constant intake of the nutrient
What type of ration is a digestion trial run on?
basal ration
Ideal indicators of digestibility
-totally indigestible
-totally unabsorbed
-no pharmacological action on the GI tract
-passes through the Gi tract at a uniform rate
-easily determined or analyzed
-preferably as a natural constituent of the feed
-
Common indicator
-Cr2O3
-SiO2
-Fe2O3
-Lignin
-plant chromagens
-polyethylene glycol
-dual indicators
-tiO2
