Forestomach Fermentative Digestion II

Question 1

define browser

Answer 1

animal that eats mainly browse
selectively feeds on highly digestible material
can NOT live on grass as efficiently as grazers

Question 2

define grazer

Answer 2

animal that eats mainly grass

Question 3

browsers eat plant material with ___ tannin

Answer 3

higher

Question 4

which gland produces tannin neutralizer?

Answer 4

parotid gland
produces proline rich proteins

Question 5

who has a larger parotid gland, browsers or grazers?

Answer 5

browsers

Question 6

is rumen content of browsers layered?

Answer 6

NOPE

Question 7

do browsers or grazers have a more homogenous rumen?

Answer 7

Question 8

browser rumens have ___ viscosity fluid. describe the separation

Answer 8

high
separation due to floatation/sedimentation less possible, gas bubble evenly distributed

Question 9

grazer rumens have ___ viscosity fluid. describe the separation

Answer 9

LOW
separation due to floatation/sedimentation and clear separation of gas layer

Question 10

what stim rumen papilla growth?

Answer 10

VFA

Question 11

VFA concentration is highest where ___ is highest

Answer 11

microbial activity

Question 12

which of the rumen compartments does VFA absorption occur in browser?

Answer 12

Question 13

which of the rumen compartments does VFA absorption occur in grazer?

Answer 13

Question 14

VFA absorption rapidly removes ___ from rumen fluid

Answer 14

acid and ion

Question 15

define mean retention time

Answer 15

time that a liquid or food particle spends in rumen
grazer > browser

Question 16

does a long MRT restrict feed intake?

Answer 16

YES since intake of roughage is limited mostly by capacity of forestomach

Question 17

describe the graph…how retention time differs between grazer and browser

Answer 17

Question 18

why is particle throughput larger in browsers?

Answer 18

they rely more on plant cell content (CHO, protein)
cell content easily fermentable
fiber has small role

Question 19

why is fluid throughput higher in grazers?

Answer 19

food particles remain longer in grazer rumen
1. removes waste and make room for new material
2. remove microbes

Question 20

removing waste and microbe stim ___ growth, causing ___ microbial yield from forestomach

Answer 20

bacterial
increase yield

Question 21

what is quorum sensing?

Answer 21

mechanism of bacteria regulates population density via autoinducer signal molecules

Question 22

autoinducers ___ in concentration as function of cell density

Answer 22

increases

Question 23

omasum functions

Answer 23

water absorption (prepares for acidic abomasum)
ingesta transport

Question 24

is omasum larger in browser or grazer?

Answer 24

grazer
since larger water absorption capacity

Question 25

why does more water flow through the grazer forestomach?

Answer 25

helps remove waste and microbial protein and facilitates better fiber fermentation

Question 26

what are the main end products of microbial VFA pathway?

Answer 26

Question 27

what form are VFA's absorbed as?

Answer 27

protonated or dissociated

Question 28

which exchanger is used at pH 6.8 for VFA intracell transport

Answer 28

VFA/bicarb exchanger

Question 29

at what pH are each of the following circles exchangers used?

Answer 29

TOP - pH 6.8 BOTTOM - lower pH

Question 30

which VFA is used for gluconeogenesis?

Answer 30

propionate

Question 31

what does acetate enter the krebs cycle as?

Answer 31

acetyl CoA

Question 32

what is the most important gluconeogenic substrate?

Answer 32

propionate MAJOR glc source

Question 33

what two main factors help regulate pH and avoid rumen acidification?

Answer 33

buffer removing VFA

Question 34

VFA accumulation in rumen ___ pH

Answer 34

lowers

Question 35

how does pH affect microbial growth rate?

Answer 35

decreased pH < 6 causes microbes to produce lactic acid

Question 36

rumen acidosis is due to a ___ overload

Answer 36

CHO

Question 37

what are symptoms of rumen acidosis?

Answer 37

unspecific variable appetite, drop in milk production, D, bloat, reduced motility, increased HR, laminitis

Question 38

lysozymes function

Answer 38

breaks hydrolytic glycosidic bonds of mucopolysaccharides

Question 39

abomasal lysozymes help make use of ___

Answer 39

microbial proteins

Question 40

lysozymes catalyze ___ of bacterial cell walls

Answer 40

hydrolysis

Question 41

where do ruminants secrete largest amount of lysozymes?

Answer 41

lumen of abomasum

Question 42

lysozymes are most active at ___ pH

Answer 42

low

Question 43

can lysozymes be cleaved by pepsin?

Answer 43

nope

Question 44

what percent of CP in fresh grass is true protein?

Answer 44

80% rest is NPN

Question 45

what affects proportion of crude protein?

Answer 45

fermentation

Question 46

describe downgrading of high biological value protein

Answer 46

rumen degradable protein is forst catabolized by microorganisms and then used to resynthesze bacterial protein

Question 47

describe upgrading of low biological value protein

Answer 47

bacteria are able to use NPN to produce microbial protein

Question 48

what's the most important NPN?

Answer 48

urea

Question 49

how is urea recycled?

Answer 49

via saliva into rumen for usage by bacteria to turn to microbial protein

Question 50

which transporters are used for urea recycling in ruminants?

Answer 50

AQP and urea transport (B)

Question 51

what determines the amount of microbial protein that reaches SI?

Answer 51

amount of dietary CP and metabolic demand

Question 52

what determines plasma urea in ruminant?

Answer 52

amount of microbial protein that reaches SI and the presence of excess ammonia in rumen

Question 53

how is pH affected during urea toxicity?

Answer 53

accumulation of rumen ammonia -> rumen pH > 7.5 -> alkaline indigestion

Question 54

describe the 3 development phases of the ruminant foregut system

Answer 54

Question 55

what's rumen drinker?

Answer 55

fast drinking with little or no suckling causes spill over into rumen since esophageal groove gets overwhelmed or is not properly formed