Ruminant GI Physiology (from E&E)

Question 1

Wtf is a ruminant

Answer 1

Animal that ruminates and has a 4 chambered stomach

Question 2

Name the 4 chambers

Answer 2

Rumen
Reticulum
Omasum
Abomasum

Question 3

Where does fermentation occur?

Answer 3

The forestomachs (Rumen, reticulum, omasum)

Question 4

The abomasum acts as the _______

Answer 4

true stomach

Question 5

Around what age, does a cow become a “ruminant”?

Answer 5

8 weeks - depends greatly on diet (could potentially be earlier)

Question 6

How do ruminants acquire the microbes that run fermentation in the rumen?

Answer 6

Environment
Mother
Other ruminants

Question 7

What is the function of the forestomachs?

Answer 7

Fermentation
Form cud
Absorb VFAs
Control outflow

Question 8

T/F: Grass, hay, and weeds are examples of forage.

Answer 8

True

Question 9

What components make up plants?

Answer 9

Cell wall
Cellulose, hemicellulose, and pectin
Lignin
Fiber (cellulose, hemicellulose, lignin)
Protein
Soluble CHOs

Question 10

What components make up grain?

Answer 10

Soluble CHOs (rapidly fermented)
Protein
Fiber

Question 11

What are cellulose, hemicellulose, and pectin?

Answer 11

CHOs

Question 12

T/F: Lignin is rapidly digested.

Answer 12

False - not digestible

Fills in spaces of cellulose and hemicellulose
Increases as the plant ages and with ambient temps

Question 13

What are VFAs? Can you name them?

Answer 13

Volatile Fatty Acids

Acetate
Butyrate
Propionate

Question 14

What do microbes do to ingested food?

Answer 14

1. Produce cellulase - breaks down cellulose, hemicellulose, and pectins into mono and oligosaccharides
2. Transform mono and oligosaccharides into VFAs
3. Break down proteins into amino acids and ammonia

Question 15

Why is it that ruminants are able to break down leafy, fibrous things?

Answer 15

Microbes produce enzymes that mammals don’t

Question 16

What organisms compose the ruminal microbe population?

Answer 16

Bacteria
Yeast
Protozoa

Question 17

What is the ratio of VFAs on a high fiber diet?

Answer 17

70 - 20 - 10
Acetate, propionate, butyrate

Question 18

What VFA is the main product in fiber digestion (forage)?

Answer 18

Acetate

Question 19

What VFA is the major substrate of gluconeogenesis?

Answer 19

Propionate
Taken to liver where it is a major substrate of gluconeogenesis

Question 20

How do ruminants deal with protein?

Answer 20

Some goes to abomasum and SI
Most broken down by extracellular microbial proteases into peptides
Peptides are absorbed by microbes

Question 21

What happens to ruminal microbes when they die?

Answer 21

Flushed to the abomasum and SI and protein is absorbed as in a monogastric

Question 22

T/F: Ruminants produce up to 25-50 gal of saliva a day.

Answer 22

True

Question 23

What is the ratio of VFAs in a grain based diet?

Answer 23

60 - 30 - 10
Acetate - Propionate - Butyrate

Question 24

Feeds of high digestibility have a rumen half life of ______ vs. ______ for poorly digestible feeds

Answer 24

30h - highly digestible
50h - poorly digestible

Question 25

How can you turn poorly digestible feeds into slightly less poor feeds?

Answer 25

Chopping or grinding feeds

Question 26

T/F: there are fixed limits to the size of the reticulorumen so rate of feed intake is equal to feed exit

Answer 26

True

Question 27

What absorbs VFAs from the rumen?

Answer 27

Rumen papillae

Question 28

About how long does it take for the rumen to accommodate changes in diet?

Answer 28

2 weeks

Question 29

What is the normal pH of the rumen?

Answer 29

5.6 to 6.8

Question 30

A pH that is too low or an overly distended rumen can result in ________ rumen motility

Answer 30

Decreased

Question 31

What is the pH of the abomasum?

Answer 31

2 to 4