CHO: Ruminant Digestion And Absorption

Question 1

Where does digestion of fiber occur in ruminants?

Answer 1

In the large intestine

Question 2

Sugars produced by fiber digestion are fermented by what?

Answer 2

Microbes

Question 3

In the rumen, carbohydrates are fermented into VFAs. They are then absorbed by?

Answer 3

Rumen wall

Question 4

What are the 4 contents of the rumen?

Answer 4

Feed, saliva, microbes, microbe waste products

Question 5

Specialized bacteria live in the rumen in what 4 ways?

Answer 5

In the liquid phase, loosely and firmly adhered to feed particles, and attached to Protozoa surface

Question 6

In rumen metabolism, carbohydrate molecules are converted into what through oxidation glycolysis?

Answer 6

Pyruvate

Question 7

What does pyruvate get converted into?

Answer 7

VFAs, CO2, CH4

Question 8

What is a disadvantage of rumen metabolism?

Answer 8

Lose energy and glucose

Question 9

What does the rumen absorb?

Answer 9

VFA and microbial protein

Question 10

What does the hind gut absorb?

Answer 10

Only VFAs

Question 11

Where do ruminants get the majority of their energy?

Answer 11

Volatile fatty acids and feed

Question 12

What are the 3 volatile fatty acids used ruminants?

Answer 12

Acetate, propionate, and butyrate

Question 13

What is the primary role of acetate and butyrate?

Answer 13

Energy

Question 14

What’s the primary role of propionate?

Answer 14

Glucose precursor

Question 15

Why is there less energy in forages?

Answer 15

Because forages are less digested, and actually take more energy to digest and they’re bulkier in the dig tract

Question 16

Where does beta- hydroxybutyric acid come from?

Answer 16

Butyrate

Question 17

Rumen acidosis means that?

Answer 17

Lactic acid production exceeds absorption

Question 18

What are some causes of acidosis?

Answer 18

Animals gorge on feed, high concentrate diet, heat stress, infrequent feeding

Question 19

What is the primary milk yield determinant?

Answer 19

Lactose synthesis

Question 20

Forage is a source of what VFA?

Answer 20

Acetate

Question 21

Propionate comes from what feedstuff?

Answer 21

Concentrates

Question 22

What do concentrates do to rumen pH?

Answer 22

Decrease it because there is less buffer production and faster rates of acid production

Question 23

Starch degradation varies with what?

Answer 23

Fermentation or digestion

Question 24

What are some things that affect fermentation rates?

Answer 24

Grain type, harvest /storage method, processing

Question 25

What does a decreased ph cause in ruminants?

Answer 25

Reduces feed intake, causes diarrhea, laminitis, liver abscesses

Question 26

What balances out rumen ph?

Answer 26

Forage consumption and carbohydrate fermentation

Question 27

What classifies acidosis as acute?

Answer 27

If ph is below 5.0

Question 28

If the rumen ph is from 5.6-5.2 and the animal has decreased feed intake what can be occurring?

Answer 28

Subacute acidosis

Question 29

What is related to organic matter (starch) intake?

Answer 29

Production rate and concentration of VFAs

Question 30

What is the optimal ph for VFA production and milk yield?

Answer 30

5.7

Question 31

The optimal forage: concentrate ratio for optimal milk yield is?

Answer 31

Either 50/50 or 60/40 (concentrate: forage)

Question 32

If amylolytic flora die at an extremely low ph, what occurs in the rumen?

Answer 32

No starch fermentation, so no VFA production

Question 33

How can we know that ruminal acidosis is occurring?

Answer 33

Diarrhea is present because VFAs are being produced in the large intestine

Question 34

What animals are at highest risk of acidosis?

Answer 34

Animals one week pre-calving and in the first few months post-calving

Question 35

What factors increase the risk for acidosis?

Answer 35

High concentrate diet, high DMI, feed method

Question 36

What are some ways we can manage acidosis?

Answer 36

By allowing time to adjust to a new diet,feeding adequate quantities of roughage, and managing consumption