Term
| At what temperature is the rumen kept? |
|
Definition
|
|
Term
True or False
The rumen is an anaerobic environment |
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Definition
|
|
Term
| What are the requirements of anaerobic fermentation? |
|
Definition
-constant nutrient supply
-water
-continuous removal of gases, VFA and NH3
-pH regulation |
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|
Term
|
Definition
| microbe species breaks down something and the product is required by another species |
|
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Term
| Which are there more of, cellulolytic or non-cellulolytic bacteria? |
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Definition
|
|
Term
| Cellulose is made up of what type of linked polymers? |
|
Definition
|
|
Term
True or False
Lignin is a CHO |
|
Definition
|
|
Term
True or False
Lignin only binds to hemicellulose |
|
Definition
|
|
Term
True or False
Lignin synthesis in plants increases as ambient temperature increases |
|
Definition
|
|
Term
| Which chemical analysis is used to find lignin? |
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Definition
|
|
Term
| prevotella reuminicola digest what? |
|
Definition
| cell wall polysaccharides (not cellulose) |
|
|
Term
| succinivibrio dextrinosolvens digest what? |
|
Definition
|
|
Term
|
Definition
| reduce CO2 and H production, but produce methane |
|
|
Term
| Which bacteria play a role in lactic acidosis development? |
|
Definition
streptococcus bovis
lactobacillus |
|
|
Term
| lactobacillus digest what.... |
|
Definition
| sugars to produce lactate |
|
|
Term
| Which are more common, protozoa or rumen bacteria? |
|
Definition
|
|
Term
True or False
protozoa populations vary depending on what the cow is consuming |
|
Definition
|
|
Term
| What do entodiniomorphids do? |
|
Definition
engulf particles/other bacteria
digest starch, cellulose, hemicellulose |
|
|
Term
| What types of microorganisms are found in the rumen, in order of population size |
|
Definition
|
|
Term
| What is the difference between plant compounds made of alpha vs beta linked polymers? |
|
Definition
Alpha: animal enzymes can digest if it is available to the enzyme
Beta: digested by microbial fermentation |
|
|
Term
| Are hemi & cellulose beta or alpha linked polymers? |
|
Definition
|
|
Term
|
Definition
non structural carbohydrates
starch, beta glucan, pectin |
|
|
Term
|
Definition
pectin (alpha)
beta glucan (B 1-3, 1-4) |
|
|
Term
| Where does the majority of cellulose digestion occur? |
|
Definition
|
|
Term
| What are the steps of cellulose digestion? |
|
Definition
1. microbial attachment
2. hydrolysis |
|
|
Term
| What is the lag period of cellulose digestion? |
|
Definition
| substrate need to be exposed (by chewing), particle must be wet (saliva), bacteria need to access and attach the fiber, bacteria need to use their extracellular enzymes |
|
|
Term
| What enzymes digest starch? |
|
Definition
|
|
Term
|
Definition
| the part of the feed that stimulates chewing, and affects rumen pH and fiber digestion |
|
|
Term
| Why do rumen microbes produce VFAs? |
|
Definition
| product of the anaerobic pathways to produce ATP for the microbes |
|
|
Term
| What are the VFA produced by microbes? (6) |
|
Definition
acetate
propionate
butyrate
isobutyrate
valerate
isovalerate |
|
|
Term
| What are the main precursors for acetate, propionate and butyrate? |
|
Definition
| CHO breakdown products e.g. glucose |
|
|
Term
True or False
Branched chain VFA are essential for fiber-digesting bacteria to produce BC AA |
|
Definition
|
|
Term
| What is the best proportion of forage:concentrates in a diet in order to maximize VFA production |
|
Definition
|
|
Term
| Why would you want a lower acetate:propionate ratio? What diet can help this? |
|
Definition
more proprionate = more energy available to animal (gluconeogenic)
-less energy lost as methane
higher concentrate diet |
|
|
Term
|
Definition
| reduce growth of methane-producing bacteria, promote production of propionate (C3) |
|
|
Term
| What VFA can help inhibit inflammation? |
|
Definition
|
|
Term
| Other than VFA, what else do microbes product? |
|
Definition
|
|
Term
| How are VFA absorbed? What effect does pH have on absorption? |
|
Definition
passive transporters
lower pH = more absorption |
|
|
Term
| What VFA is a precursor for fat synthesis? |
|
Definition
|
|
Term
| What VFA is converted to ketone bodies? |
|
Definition
|
|
Term
| Why is propionate essential to ruminants |
|
Definition
| most glucose is broken down in the rumen. propionate is the only gluconeogenic VFA |
|
|
Term
| What is the relationship between cobalt and B12, and dying due to lack of glucose? |
|
Definition
cobalt is part of the B12 structure
lack of B12 = propionate cannot be converted to glucose |
|
|
Term
brown salt is what?
What does iodized salt prevent? what does cobalt-iodized salt prevent? |
|
Definition
trace mineralized salt
goiter
B12 deficiency |
|
|
Term
| Where does blood glucose come from in ruminants? |
|
Definition
propionate (C3)
glycerol
AAs (aspartate, alanine, glutamine) |
|
|
Term
| What factors affect ruminal fermentation? (4) |
|
Definition
diet composition & particle size
intake
passage rate
pH of rumen |
|
|
Term
| How does the proportion of cell contents in the diet vs NDF affect rumen fermentation? |
|
Definition
| higher cell contents = fewer and less active fiber digesters |
|
|
Term
| How does particle size influence rumen fermntation? |
|
Definition
| smaller size = less time spent in reticulo rumen, may escape rumen before microbes ferment |
|
|
Term
| How does a high pH affect rumen fermentation? |
|
Definition
| higher pH allows rumen to leave the RR, decreasing the use of ammonia by the microbes |
|
|
Term
| High pH increases production of what? Low pH? |
|
Definition
|
|
Term
| What causes formation of a rumen mat? Why does it float? |
|
Definition
longer partially digested fibers get mixed in with new ingesta as rumen 'churns', and microbial fermentation occurs here
gases get trapped in mat and make it buoyant |
|
|
Term
| Why is a rumen mat important? |
|
Definition
stimulates retention of particles in RR, increases utilization of feed
stimulates rumination = more saliva = more buffers = more control of pH |
|
|
Term
| When do particles escape the rumen mat? |
|
Definition
| when chemical/physical digestion reduces them in size enough that they fall to the ventral part of the rumen |
|
|
Term
| What affects the integrity of the rumen mat? |
|
Definition
| particle size of the forages in the diet (too small) |
|
|
Term
| What microbes are most important for protein digestion? Which ones cannot digest protein? |
|
Definition
bacteria
all 3 can digest proteins |
|
|
Term
|
Definition
| protein that can be degraded in the rumen |
|
|
Term
|
Definition
| as a source of N for microbes |
|
|
Term
| Which CHO promote better MP synthesis? |
|
Definition
|
|
Term
| What happens to fats in the rumen? |
|
Definition
lipolysis frees FAs
they are bihydrogenated (double bounds are reduced) to become more saturated
FAs incorporated into cells by bacteria |
|
|
Term
| What effect do fats have on fermentation? |
|
Definition
coats fibers, reducing rumen fermntation
inhibits microbial activities (PUFA can be toxic to microbes) especially fibrolytic |
|
|
Term
| how does dietary fat alter acetate:propionate ratio? |
|
Definition
|
|
Term
True or False
the primary source of lipid absorption is the rumen |
|
Definition
|
|
Term
| Is rumen fermentation an efficient process? |
|
Definition
|
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