Ruminant GI Physiology (from E&E) Flashcards
Wtf is a ruminant
Animal that ruminates and has a 4 chambered stomach
Name the 4 chambers
Rumen
Reticulum
Omasum
Abomasum
Where does fermentation occur?
The forestomachs (Rumen, reticulum, omasum)
The abomasum acts as the _______
true stomach
Around what age, does a cow become a “ruminant”?
8 weeks - depends greatly on diet (could potentially be earlier)
How do ruminants acquire the microbes that run fermentation in the rumen?
Environment
Mother
Other ruminants
What is the function of the forestomachs?
Fermentation
Form cud
Absorb VFAs
Control outflow
T/F: Grass, hay, and weeds are examples of forage.
True
What components make up plants?
Cell wall
Cellulose, hemicellulose, and pectin
Lignin
Fiber (cellulose, hemicellulose, lignin)
Protein
Soluble CHOs
What components make up grain?
Soluble CHOs (rapidly fermented)
Protein
Fiber
What are cellulose, hemicellulose, and pectin?
CHOs
T/F: Lignin is rapidly digested.
False - not digestible
Fills in spaces of cellulose and hemicellulose
Increases as the plant ages and with ambient temps
What are VFAs? Can you name them?
Volatile Fatty Acids
Acetate
Butyrate
Propionate
What do microbes do to ingested food?
- Produce cellulase - breaks down cellulose, hemicellulose, and pectins into mono and oligosaccharides
- Transform mono and oligosaccharides into VFAs
- Break down proteins into amino acids and ammonia
Why is it that ruminants are able to break down leafy, fibrous things?
Microbes produce enzymes that mammals don’t
What organisms compose the ruminal microbe population?
Bacteria
Yeast
Protozoa
What is the ratio of VFAs on a high fiber diet?
70 - 20 - 10
Acetate, propionate, butyrate
What VFA is the main product in fiber digestion (forage)?
Acetate
What VFA is the major substrate of gluconeogenesis?
Propionate
Taken to liver where it is a major substrate of gluconeogenesis
How do ruminants deal with protein?
Some goes to abomasum and SI
Most broken down by extracellular microbial proteases into peptides
Peptides are absorbed by microbes
What happens to ruminal microbes when they die?
Flushed to the abomasum and SI and protein is absorbed as in a monogastric
T/F: Ruminants produce up to 25-50 gal of saliva a day.
True
What is the ratio of VFAs in a grain based diet?
60 - 30 - 10
Acetate - Propionate - Butyrate
Feeds of high digestibility have a rumen half life of ______ vs. ______ for poorly digestible feeds
30h - highly digestible
50h - poorly digestible
How can you turn poorly digestible feeds into slightly less poor feeds?
Chopping or grinding feeds
T/F: there are fixed limits to the size of the reticulorumen so rate of feed intake is equal to feed exit
True
What absorbs VFAs from the rumen?
Rumen papillae
About how long does it take for the rumen to accommodate changes in diet?
2 weeks
What is the normal pH of the rumen?
5.6 to 6.8
A pH that is too low or an overly distended rumen can result in ________ rumen motility
Decreased
What is the pH of the abomasum?
2 to 4
