ANSC 221 Exam 2
Where is fat digested, primarily, and how? What is needed to do a good job? -
ANS-Occurs in small intestine
Bile is needed to emulsify fat to be digested by enzymes
Why don't the protein digesting enzymes digest the cells that make them? - ANS-Pepsin
is in the inactive form when secreted
How is digestion of carbohydrate different in the ruminant animal (cow) than the
nonruminant? - ANS-Ruminant - digested by bacteria into VFA's
Non-ruminant - broken into glycogen; used for blood sugar or converted to ATP, stored
as fat
Bicarbonate in cow vs pig vs horse - ANS-Bicarbonate from pancreas in both, secreted
from different locations
Where do cows vs pigs get glucose - ANS-All animals need glucose
Cows - milking get glucose from lactose; glucose eaten is broken down by microbes, so
need to make their own - glycogenesis
Pig - break down glucose from feed
Non-ruminant - glucose from diet, break down carbs and can make glucose from other
things (amino acids)
Why do protein digesting proteins digest themselves - ANS-Protein digestive enzyme is
made in an inactive form
Pepsinogen (inactive) is secreted, becomes active (pepsin) with HCl
Protein digestion in ruminant - ANS-Bacteria break down DIP to make bacterial protein,
which is later digested with UIP in small intestine, where amino acids are absorbed.
VFA's can be absorbed in rumen wall
Degradable Intake Protein (DIP) vs Undegradable Intake Protein (UIP) - ANS-DIP is
what microbes get to first, bacteria take it to make proteins
UID passes through rumen untouched and ends up in small intestine, where digestive
enzymes can digest it
,If you feed proteins easier to break down, it will break down. If less digestible, more
lysine can get to animal (more UIP)
Digestion of protein in non-ruminant - ANS-Amino acids enter bloodstream and supply
cells w/ amino acids for protein synthesis; the amino acids not used are deaminated and
used for energy
NPN is not useful bc there are not microbes to break it down for use.
Broken down by enzymes into amino acids, absorbed in small intestine
How do we determine the value of a feedstuff? How do we determine the value of its
protein? of its energy? - ANS-Analyze and run trials to evaluate the protein amount,
value, energy value, etc (like the homework)
What is meant by: protein digestibility, nitrogen balance, nitrogen retention, biological
value, true digestibility or BV vs apparent digestibility or BV? HW3 - ANS-Protein
digestibility - amount of usable protein
Nitrogen balance - amount of available nitrogen
Biological value - proportion of nitrogen retained
True vs apparent BV - true is what's retained, apparent is what's taken in
What losses of nitrogen occur from the body? - ANS-Urine and feces
Why is the digestibility of nitrogen and the digestibility of protein the same thing? -
ANS-Measure protein as crude protein (N*6.25)
What does 'endogenous' mean? How could you determine the endogenous secretion?
What are the 2 different energy systems? - ANS-Means the nitrogen is coming out from
the body instead of the evaluated feed
Determine the secretion by not feeding any protein, and see the amount of protein
secreted (assuming rate of secretion doesn't change) - can also use isotopes
The two energy systems - ANS-TDN - older system to estimate energy on hydrocarbon
basis
Choleric system to measure energy based on intake (kcal) for digestible and
metabolized energy - more complicated
What is TDN and how is it calculated? What is the lowest value you could have? What
is the highest value you could have? how? - ANS-Index of energy on hydrocarbon basis
, Calculated by
Lowest - 0
Highest - 225
Generally fall between 40 - 100
What is gross energy, digestible energy, metabolisable energy, net energy? What is the
difference between each of them. Why is fat of more value in the summer when it is
hot? - ANS-Gross energy - all energy in a feed
Digestible energy - how much energy doesn't end up in feces
Metabolizable energy - energy accounted for after feces, urine, and gas
Net energy - energy accounted for after feces, urine, gas, and HEAT INCREMENT
Fat more valuable in summer bc less excess heat load to get rid of compared to cooler
weathers
What is heat increment? - ANS-Waste heat
What does emulsify mean? Where is it accomplished? - ANS-Means get fat into water
phase (need detergent to get oil off hands in water)
Happens with bile (produced in liver, stored in gall bladder, secreted in small intestine)
How could 2 feeds have the same TDN and DE values, but be of different energy use to
the animal? - ANS-Neither takes everything into account
DE loses some energy in urine, and doesn't account for heat increment; so different net
energy
Mostly true in forage feeds
How could a feed be of little protein value even though its biological value is high? How
could a feed be of little protein value even though its digestibility is high? - ANS-High
biological value means high in amino acids, but may not be super digestible
Little protein could be due to missing amino acids, which means many proteins can be
wasted
What does biological value depend on, or what is it indicative of (and the answer is not
digestibility). - ANS-Depends on relies on digested protein retained
What is NPN? What are some examples? Where is it useful? - ANS-NPN is non-protein
nitrogen
EX) urea,
Useful to ruminants bc microbes, not useful to non-ruminants
Where is fat digested, primarily, and how? What is needed to do a good job? -
ANS-Occurs in small intestine
Bile is needed to emulsify fat to be digested by enzymes
Why don't the protein digesting enzymes digest the cells that make them? - ANS-Pepsin
is in the inactive form when secreted
How is digestion of carbohydrate different in the ruminant animal (cow) than the
nonruminant? - ANS-Ruminant - digested by bacteria into VFA's
Non-ruminant - broken into glycogen; used for blood sugar or converted to ATP, stored
as fat
Bicarbonate in cow vs pig vs horse - ANS-Bicarbonate from pancreas in both, secreted
from different locations
Where do cows vs pigs get glucose - ANS-All animals need glucose
Cows - milking get glucose from lactose; glucose eaten is broken down by microbes, so
need to make their own - glycogenesis
Pig - break down glucose from feed
Non-ruminant - glucose from diet, break down carbs and can make glucose from other
things (amino acids)
Why do protein digesting proteins digest themselves - ANS-Protein digestive enzyme is
made in an inactive form
Pepsinogen (inactive) is secreted, becomes active (pepsin) with HCl
Protein digestion in ruminant - ANS-Bacteria break down DIP to make bacterial protein,
which is later digested with UIP in small intestine, where amino acids are absorbed.
VFA's can be absorbed in rumen wall
Degradable Intake Protein (DIP) vs Undegradable Intake Protein (UIP) - ANS-DIP is
what microbes get to first, bacteria take it to make proteins
UID passes through rumen untouched and ends up in small intestine, where digestive
enzymes can digest it
,If you feed proteins easier to break down, it will break down. If less digestible, more
lysine can get to animal (more UIP)
Digestion of protein in non-ruminant - ANS-Amino acids enter bloodstream and supply
cells w/ amino acids for protein synthesis; the amino acids not used are deaminated and
used for energy
NPN is not useful bc there are not microbes to break it down for use.
Broken down by enzymes into amino acids, absorbed in small intestine
How do we determine the value of a feedstuff? How do we determine the value of its
protein? of its energy? - ANS-Analyze and run trials to evaluate the protein amount,
value, energy value, etc (like the homework)
What is meant by: protein digestibility, nitrogen balance, nitrogen retention, biological
value, true digestibility or BV vs apparent digestibility or BV? HW3 - ANS-Protein
digestibility - amount of usable protein
Nitrogen balance - amount of available nitrogen
Biological value - proportion of nitrogen retained
True vs apparent BV - true is what's retained, apparent is what's taken in
What losses of nitrogen occur from the body? - ANS-Urine and feces
Why is the digestibility of nitrogen and the digestibility of protein the same thing? -
ANS-Measure protein as crude protein (N*6.25)
What does 'endogenous' mean? How could you determine the endogenous secretion?
What are the 2 different energy systems? - ANS-Means the nitrogen is coming out from
the body instead of the evaluated feed
Determine the secretion by not feeding any protein, and see the amount of protein
secreted (assuming rate of secretion doesn't change) - can also use isotopes
The two energy systems - ANS-TDN - older system to estimate energy on hydrocarbon
basis
Choleric system to measure energy based on intake (kcal) for digestible and
metabolized energy - more complicated
What is TDN and how is it calculated? What is the lowest value you could have? What
is the highest value you could have? how? - ANS-Index of energy on hydrocarbon basis
, Calculated by
Lowest - 0
Highest - 225
Generally fall between 40 - 100
What is gross energy, digestible energy, metabolisable energy, net energy? What is the
difference between each of them. Why is fat of more value in the summer when it is
hot? - ANS-Gross energy - all energy in a feed
Digestible energy - how much energy doesn't end up in feces
Metabolizable energy - energy accounted for after feces, urine, and gas
Net energy - energy accounted for after feces, urine, gas, and HEAT INCREMENT
Fat more valuable in summer bc less excess heat load to get rid of compared to cooler
weathers
What is heat increment? - ANS-Waste heat
What does emulsify mean? Where is it accomplished? - ANS-Means get fat into water
phase (need detergent to get oil off hands in water)
Happens with bile (produced in liver, stored in gall bladder, secreted in small intestine)
How could 2 feeds have the same TDN and DE values, but be of different energy use to
the animal? - ANS-Neither takes everything into account
DE loses some energy in urine, and doesn't account for heat increment; so different net
energy
Mostly true in forage feeds
How could a feed be of little protein value even though its biological value is high? How
could a feed be of little protein value even though its digestibility is high? - ANS-High
biological value means high in amino acids, but may not be super digestible
Little protein could be due to missing amino acids, which means many proteins can be
wasted
What does biological value depend on, or what is it indicative of (and the answer is not
digestibility). - ANS-Depends on relies on digested protein retained
What is NPN? What are some examples? Where is it useful? - ANS-NPN is non-protein
nitrogen
EX) urea,
Useful to ruminants bc microbes, not useful to non-ruminants
