ANSC 221 Exam 2 Questions With Verified
Answers
Where is fat digested, primarily, and how? What is needed to do a good job?
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?
Pepsin is in the inactive form when secreted
How is digestion of carbohydrate different in the ruminant animal (cow) than the nonruminant?
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
Bicarbonate from pancreas in both, secreted from different locations
Where do cows vs pigs get glucose
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
Protein digestive enzyme is made in an inactive form
Pepsinogen (inactive) is secreted, becomes active (pepsin) with HCl
Protein digestion in ruminant
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)
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
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?
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
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?
Urine and feces
Why is the digestibility of nitrogen and the digestibility of protein the same thing?
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?
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
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?
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?
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?
Waste heat
Answers
Where is fat digested, primarily, and how? What is needed to do a good job?
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?
Pepsin is in the inactive form when secreted
How is digestion of carbohydrate different in the ruminant animal (cow) than the nonruminant?
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
Bicarbonate from pancreas in both, secreted from different locations
Where do cows vs pigs get glucose
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
Protein digestive enzyme is made in an inactive form
Pepsinogen (inactive) is secreted, becomes active (pepsin) with HCl
Protein digestion in ruminant
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)
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
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?
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
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?
Urine and feces
Why is the digestibility of nitrogen and the digestibility of protein the same thing?
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?
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
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?
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?
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?
Waste heat
