GI Nutrition- The rumen complex

Question 1

What is the purpose of fermentation?

Answer 1

Fermentation transform forage into simple sugars that rumen microorganisms can use for growth

Question 2

What are the by-products of fermentation?

Answer 2

Volatile fatty acids

Question 3

What do microbes provide to ruminants?

Answer 3

digestion of cellulose, amino acids, protein, vitamin B

Question 4

What are calfs?

Answer 4

monogastrics

Question 5

Oesophageal groove

Answer 5

closed tube that allows milk to bypass the rumen and go straight to the abomasum, this prevents milk from being fermented

Question 6

What effects the growth rates of calfs?

Answer 6

energy and protein contents of milk, volume and frequency that the milk is supplied

Question 7

What should calves have first after colostrum?

Answer 7

Milk replacer-it is digested in the abomasum and bypasses the rumen

Question 8

When should concentrates be fed?

Answer 8

From 3-4 days old, they produce butyrate and propionate which increases papillae size and number which increases the overall size of the rumen

Question 9

Why should you not feed fibre from birth?

Answer 9

rumen is undeveloped so they cannot digest it, digesting milk and forages does not help papillae to grow

Question 10

What age should you be concentrate feeding?

Answer 10

3-4 weeks

Question 11

What is the benefit of feeding fibre?

Answer 11

stimulates rumination and saliva production, increases pH, produces acetate, reduces keratinisation

Question 12

Why are VFA’s important?

Answer 12

size and length of ruminal papillae respond to VFA’S

Question 13

What are the benefits of feeding forages?

Answer 13

Increases size of rumen, encourages calf to ruminate

Question 14

Why do calves need water?

Answer 14

increases intake of grain, reduces incidence of diarrhoea, reduces acidosis

Question 15

What is the structure of fibre?

Answer 15

a polysaccharide which forms straight chains (B-glucans), mammalian enzymes cannot break it down

Question 16

What is the ruminant stomach?

Answer 16

4 chambers, 3 of which do not contain digestive enzymes- contains huge number of microorganisms that ferment fibre

Question 17

How does the rumen work?

Answer 17

Cycles of contractions, belching removes gases every second contraction

Question 18

What is the function of the rumen?

Answer 18

(the largest chamber, on the left of the stomach) storage site and fermentation, absorbs VFA’s and nutrients

Question 19

What is the function of the reticulum?

Answer 19

traps large feed particles to make sure they don’t enter the next section of the stomach before they are digested, regurgitation of ingesta followed by re-mastication and re-swallowing

Question 20

What is rumination?

Answer 20

Eating low quality fibre that requires mechanical breakdown

Question 21

How does chewing the cud occur?

Answer 21

Swallow fibre whole, rip it up using the tongue- regurgitating and chewing/ruminating the food- maximises intake of food then moves it to an area of safety

Question 22

How much saliva do ruminants produce during rumination?

Answer 22

150-250 Litres

Question 23

What occurs during rumination?

Answer 23

Bacteria ferment fibre, fibre is digested by bacteria and used to grow- by-products of fermentation are released into the rumen (By-products are VFA’s)

Question 24

What happens to plant carbohydrates?

Answer 24

Bacteria bind to the plant cell wall and break them down into smaller monosaccharides, glucose and other monosaccharides are released which are then rapidly absorbed by microbes

Glycolysis releases pyruvate which is transformed into VFA’s

Question 25

What happens to protein in the rumen?

Answer 25

bacteria break down protein and fibre into amino acids, some of them are used by the bacteria to grow

Question 26

What are the bacterial byproducts of protein digestion?

Answer 26

Ammonia and VFA’s

Question 27

What happens to plant protein?

Answer 27

bacteria pass into small intestines and protein digestion provides amino acids for the cow, ammonia and VFA’s are required to make bacterial protein

Question 28

what is RDP?

Answer 28

rumen degradable protein, feeds the rumen bacteria and ensures an adequate supply of microbial protein, microbial protein is the highest quality available

Question 29

what is RUDP?

Answer 29

undegradable protein, passes through the rumen unchanged and is digested in the small intestine