Rumination

Question 1

What is rumination?

Answer 1

The process of regurgitation, remastication and redeglutition

Question 2

Describe how regurgitation occurs

Answer 2

Thorax expands - increased negative pressure. 
Cardiac sphincter opens
Diaphragm contracts
Reverse peristalsis into oral cavity
Liquid immediately swallowed back down.

Question 3

Which parts of the stomach are the forestomach? Which is the true stomach?

Answer 3

omasum, rumen, reticulum

Abomasum

Question 4

What type of epithelium is found in the forestomach?

Answer 4

Stratified squamous

Question 5

Describe the size and lining of the reticulum

Answer 5

Small
Smooth muscle
Ridges

Question 6

What remains in the reticulum?

Answer 6

Very dense particles, stones

Question 7

Where does long grass/hay/straw float? Where does gas collect

Answer 7

Hay - bottom of dorsal sac

gas - top of dorsal sac

Question 8

Why are the stomach chambers less defined in browsers?

Answer 8

More rapid fermentation through rumen and reticulum

Question 9

How many times does rumination occur per day

Answer 9

6-10

Question 10

Which is the main fermentation chamber?

Answer 10

Rumen

Question 11

What separates the rumen into dorsal and ventral sac

Answer 11

Longitudinal groove

Question 12

What does the vertical groove seperate the rumen into?

Answer 12

Caudodorsa and ventral blind sac

Question 13

What increases the surface area of the rumen? Does it contain smooth muscle?

Answer 13

Papillae

No

Question 14

What regulates the contraction of the rumen?

Answer 14

Short reflexes\

Via vagus nerve

Question 15

Which side of the body is the omasum on? What structure does the omasum have?

Answer 15

Right

Multiple leaves with papillae

Question 16

What regulates the passage of fermented material from reticulum to omasum?

Answer 16

Reticulo-omasal orifice

Question 17

What type of cells line the abomasum?

Answer 17

Columnar epithelial cells

Glands

Question 18

There is a constant flow from the rumen to the abomasum. The pH is higher than the simple stomach, but is still acidic enough to kill microbes. Why is it less acidic?

Answer 18

Alkaline fermentation fluid

Question 19

What are the 2 types of rumino reticulum contractions?

Answer 19

Primary - mixing

Secondary - eructation

Question 20

During rumination, which contractions precede primary ones?

Answer 20

Extra reticular contactions

Question 21

What are the 4 stages of primary contractions?

Answer 21

First reticular contraction
Second reticular contraction
Dorsal rumen contraction
Ventral rumen contaction

Question 22

How many litres are eructed per day due to fermentation?

Answer 22

2000-4000

Question 23

When can eructation not occur?

Answer 23

When animal lying on side

Gastric torsion

Question 24

Describe the process which leads to eructation?

Answer 24

Thorax expands - negative pressure

Most gas inhaled, some escapes

Question 25

WHat happens if there is failure to eructate? What might cause this?

Answer 25

Bloating | Oesophageal obstruction, tumour, eating clover

Question 26

What is frothy bloat?

Answer 26

bloat caused by smaller bubbles that don’t group into larger bubbles

Question 27

What can the pressure of bloating cause?

Answer 27

Cardiac/respiratory distress

Question 28

Which NS regulates forestomach motility? WHich nerve? Where is the control centre?

Answer 28

Autonomic Vagus Medulla

Question 29

Which part of the stomach is developed at birth? When does the other part do stomach?

Answer 29

Abomasum | Forestomach develops when eating roughage, 2-3 weeks

Question 30

What stimulates fermentation microbes to develop?

Answer 30

Mothers licking | Ingestion

Question 31

How does milk bypass the fermentation chamber? What stimulates this?

Answer 31

Oesophageal groove. | Warm milk

Question 32

What happens if there is too much milk or oesophageal groove failure?

Answer 32

Lactose fermented to lactic acid | Upsets microbes

Question 33

What is microbial fermentation? What conditions is it in?

Answer 33

Chemical breakdown of food to VFAs by microbes

Question 34

What would happen if microbial fermentation was an aerobic process/

Answer 34

Food would be fully broken down to CO2 and H20 | No energy would be provided to host

Question 35

What does the ruminoreticulum do?

Answer 35

Provide environment for microbes | Slow down transit time

Question 36

How does oxygen gain entry into the stomach?

Answer 36

Through blood | Through swallowed air

Question 37

Microbial fermentation is only 90% efficient. Why is this?

Answer 37

10% lost by methane production

Question 38

What type of organisms are found in microbial fermentation

Answer 38

Bacteria - amylolytic, cellulolytic, proteolytic, methanogenic, lactate utilisers Large Protozoa - less efficient Fungi - aerobic

Question 39

Describe the movement of water, ammonium ions and VFAs in the stomach

Answer 39

Ammonium ions taken up by microbes Water enters rumen VFAs absorbed by host

Question 40

What is rumen acidosis? Why is this bad? How is it treated?

Answer 40

Sudden increase of H+ due to VFAs (too much hCHO) Damages epithelium, causes water absorption into rumen —> dehydration Alkaline IV fluid

Question 41

Which molecules are not available to the host, due to being taken up by microbes?

Answer 41

Monosaccharides Di/tri peptides AA

Question 42

Which is the only VFA that can be used in gluconeogenesis? how is it formed?

Answer 42

Propionate | Anaerobic glycolysis of pyruvate

Question 43

What can non-protein nitrogen be used for?

Answer 43

Protein synthesis via microbes

Question 44

Non protein nitrogen is essential. How much is found in grass? What about haylage?

Answer 44

15% | 70% due to fermentation