Measurement of Feed Flashcards
What factors affect nutrient utilization?
species, age, physiological, disease conditions, type of feed and processing, presence of antinutritional factors in feed, type of digestive tract, level and balance of nutrients, and physical form of food
What animal nutrition trials are there?
growth trials, production trials, digestibility trials, testing different treatments, basic research to understand mechanisms of change
What are Growth Trials?
compare weight gain upon feeding different feeds
total feed consumption and weight gain are monitored and feed efficiency is calculated
WEIGHT GAIN PER UNIT OF FEED=
total weight gain/total feed consumed
Results from growth trials can be affected by voluntary feed intake which is affected by:
feed palatability, physical characteristics, and nutrient consent
What are digestion trials?
evaluation of feed is more precise and is expressed in terms of digestibility of each of the nutrients rather than total content in feed
Why are digestion trials completed?
to determine the proportion of nutrients in the feed that are digested and absorbed from the gi tract
what is the definition of digestibility?
the fraction of a nutrient ingested that is digested and absorbed by the animals
What kind of sample is collected during digestion trials?
fecal
Results obtained through fecal digestibility are/are not a true reflection of the digestibility of the test diet
are not
Fecal digestibility is termed __________ which represents the difference between the amount digested and the amount appearing in feces
apparent digestibility
apparent digestibility (%)=
nutrient intake-nutrient loss *100/nutrient intake
Monitoring food intake and fecal collection is:
time consuming, laborious, and difficult to conduct in grazing animals
What two factors affect the amount of DE in a feed?
GE content of feed and digestibility of energy containing components
What factors affect digestibility?
species, breed, age, becoming accustomed to feed
True digestibility of a nutrient is the proportion of the dietary intake that is _____ from the GI tract, excluding _________
absorbed; endogenous contribution
Ileal digestibility can be determined with the use of animals fitted with a ________ or by collecting ____________
ileal cannula, ileal digest at slaughter
Since a quantitative collection of ileal digesta is not possible, inert _________ are used to estimate nutrient digestibility. these markers should:
digestibility markers; not interfere with digestive processes, not be absorbed, behave similarly to the nutrient interest in the gi tract
Due to the high cost of conducting digestion trials, in vitro techniques simulating ____________ are conducted in ruminant animals fitted with ____________
rumen fermentation, rumen fistula
Rumen fistulas are used for:
screening feedstuffs or studying rumen function and metabolism
Apparent digestibility measures the digestibility of amino acids of both ______ and __________ origins, on the other hand, includes a correction for endogenous _________ secretions
endogenous and dietary; amino acid
Digestibility coefficients (DC) allow:
quantification of digestibility
