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Animal Nutrition 2 > The Ruminant (1) > Flashcards

The Ruminant (1) Flashcards

1
Q

How many stomachs does a cow have?

A

4

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2
Q

At what part of the tract does microbial digestion take place?

A

The beginning

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3
Q

What happens once starch enters the rumen?

A

It will be digested by microbes

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4
Q

What are all carbohydrates broken down into?

A

Glucose

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5
Q

What is the primary monosaccharide?

A

Glucose

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6
Q

Is glucose easy to break down?

A

yes, very

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7
Q

Pyruvate

A

Quickly broken down and utilised by the the rumen into VFA’s

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8
Q

What are the main VFA’s ?

A

Acetate, propionate and butyric

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9
Q

What are the main waste products from a ruminant?

A

CO2 and methane

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10
Q

What is produced when carbs are digested in the rumen?

A

Production of Acetate, Propionate and Butyric

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11
Q

What is only sometimes produced in the rumen?

A

Lactate

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12
Q

What happens when lactate builds up?

A

Acidosis

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13
Q

Will all carbs that enter the rumen digested in the rumen?

A

No

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14
Q

What does digestibility tell us?

A

How much feed is digested as it passes through

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15
Q

Digestibility of silage?

A

70%

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16
Q

What happens when cellulose is passed through the rumen undigested?

A

It has a very little chance of being digested

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17
Q

What happens when maize passes through the rumen?

A

Becomes available to be digested in the large intestine

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18
Q

Facts in relation to Corke Park?

A

-29% of the global surface is land
-Only 2/3 heritable
-50% is agricultural land
-70% for livestock
-30% for crops

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19
Q

What is the main source of energy?

A

VFA’s

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20
Q

What is a ruminant?

A

Has the ability to use fermentation as a method of feed digestion

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21
Q

Ruminants have a symbiotic relationship with what?

A

Microorganisms

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22
Q

What is the rumen a habitat for?

A

Growth

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23
Q

What are microbes?

A

Nutrients that would otherwise be unavailable

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24
Q

How many types of ruminants are there?

A

Over 180

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25
Q

What types of ruminants are there?

A
  • Concentrate selectors
  • Intermediate types
  • Grass/roughage eaters
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26
Q

Concentrate Selectors

A
  • Don’t have large rumen
  • Eat small meals regularly
  • Eat the most nutritious part
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27
Q

Intermediate types

A
  • 8 hours grazing
  • 8 hours ruminating
  • 8 hours of either
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28
Q

Human edible protein output-input ratio for sheep and goats

A
  • 25.5:1 return
  • 24.5 gram of human edible protein output for 1 gram of protein
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29
Q

Human edible protein output-input ratio for cattle

A
  • 15:1 return
  • 15 grams of human edible protein output for 1 gram of protein
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30
Q

What part in the true stomach?

A

Abomasum

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31
Q

What stomach squeezes out water?

A

Omasum

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32
Q

What stomach is the ‘reseeding jar’?

A

Reticulum

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33
Q

Functions of the rumen?

A
  1. Storage
  2. Structure of carbohydrates
  3. Synthesis of microbial protein
  4. Synthesis of essential micronutrients such as Vitamin B
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34
Q

Ruminant GI has 4 compartments

A
  1. Storage
  2. Mixes food with microbes
  3. Reduces particle size
  4. Eliminates gases and regulates flow of digesta to gut
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35
Q

Volume of rumen

A

80-100 L

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36
Q

What is the rumen lined with?

A
  • Filiform and foliate epithelium layers
  • Increased SA for VFA absorption
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37
Q

Rumen Pillars

A
  • Contractions force digesta across pillars and mixes it
  • Inoculates digesta with MO
  • Transfer of VFA to papillae
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38
Q

Cranial pillar

A
  • Holds digesta away from the oesophagus
  • Allows new food to enter the rumen(no physical)
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39
Q

Why is it important to leave space for gases to be released in the rumen?

A

As if they are not released, there will be a build up of gases and this may cause bloat

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40
Q

What is the first compartment that food travels into from the oesophagus?

A

The reticulum

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41
Q

What does the reticulum hold?

A

-Any foreign materials (stones) that enter
- If these travel down the tract further, it may puncture the tract of block it
- Small particles transferred to omasum. This controls the flow rate of digesta

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42
Q

What structure is on the epithelium of the reticulum?

A

honeycomb

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43
Q

Why does the reticulum have an essential role in rumination?

A

Large particles are forced back into oesophagus and particle size is reduced

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44
Q

What does ruminants convert non-human edible carbohydrates into?

A

Human available nutrients

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45
Q

What do ruminants and their microbiome have the capacity to create?

A
  • Protein and synthesis other essential nutrients
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46
Q

What is required by microbes in the rumen to synthesis vitamin B12?

A

Cobalt

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47
Q

What do microbes utilise?

A

Protein for growth

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48
Q

Omasum structure

A
  • Epithelium arranged in folds called laminae
  • These filter digesta
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49
Q

What happens when the laminae contract?

A
  • Acts as a vacuum to absorb nutrients and small particles
  • Water, VFA’s, bacteria, MP, particles (<1mm)
  • These are absorbed via reticulo-omasal orifice
  • Large particles trapped between laminae are flushed back into the rumen for rumination
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50
Q

Omasum shape

A
  • Spherical
  • Size of a football
  • Muscular folds of tissue inside
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51
Q

Function of papillae

A
  • Absorption
  • Removes moisture from digesta as it moves down the digestive tract
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52
Q

Mineral leftover in the omasum

A

Reduced DM content

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53
Q

What does the omasum absorb?

A

Most minerals that aren’t absorbed in the rumen

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54
Q

What does the omasum act as a buffer between?

A

The rumen and the abomasum

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55
Q

Is the gastric stomach low or high pH

A

Low

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56
Q

What is the only stomach with secretions

A
  • Abomasum
  • Protected by mucous from pepsin and HCl
  • Only begins to take place in the abomasum
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57
Q

what stage is protein digestion in the abomasum

A
  • The first
  • Continued in the small intestine
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58
Q

What does the abomasum act as a buffer between?

A
  • The high rumen pH and the low pH in the abomasum
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59
Q

What happens when there is a decrease in pH in the abomasum

A

Acidosis

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60
Q

What happens when there is an increase in pH in the abomasum

A

Diarrhea

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61
Q

What happens when acidosis gets into the blood

A

The animal dies

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62
Q

What does the mucous in the abomasum do?

A

Protects the lining of the stomach from HCl and from protein digesting enzymes

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63
Q

Microbial Protein in the Abomasum

A

-Bacteria synthesis AA’s
- Comprises AA’s in the bacterial cells
- Low pH kills bacteria
- When killed, they become another AA and are digested for example dead bacteria, protozoa etx

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64
Q

For microbial protein to be utilised in the abomasum, what must happen?

A

Bacteria must be killed

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65
Q

What is the small intestine of a ruminant compared to?

A

The small intestine of a monogastric

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66
Q

What does the small and large intestine contain?

A
  • Secretions from the pancreas and liver
  • Enzymatic digestion of protein, fats, sugars and starch
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67
Q

Where is water mainly absorbed?

A

Large intestine

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68
Q

What percentage fermentation takes place in the large intestine?

A
  • <10-15%
  • Some fermentation of carbohydrates, can be important in some cases
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69
Q

What happens when cows reach their peak fiber intake?

A
  • The fiber is not digested in the rumen but instead in the small and large intestine
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70
Q

Is fermentation in the large intestine as effective as in the rumen?

A

No

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71
Q

Can animals utilise microbial protein in the small intestine?

A
  • No
  • They dont have a chance to
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72
Q

Where is the next stop after the intestines?

A

Faeces

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73
Q

What are the simple organisms that are the foundations of life?

A

Bacteria

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74
Q

Where have microbiomes never been cultured?

A
  • Outside of the rumen
  • The more we learn, the less we know
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75
Q

What do we want microbiomes to do?

A

Reduce the amount of methane being produced

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76
Q

What are microbiome very resistance to?

A

Change

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77
Q

What is bacteria needed for

A
  • To break down grass different to digesting concentrates
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78
Q

How long does it take for microbiome to chance?

A
  • 3-4 weeks
  • Resilient
  • Plastic identity
  • Always springs back
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79
Q

What is rumen fluid dense in?

A

Bacteria

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80
Q

What is bacteria essential for?

A

Feed formation

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81
Q

What percentage of bacteria is bound to feed particles?

A

75%

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82
Q

What doe bacteria digest?

A

Sugar, starch, lipids, protein

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83
Q

How many bacteria per ml of rumen fluid?

A

1 billion

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84
Q

What bacteria are stuck to the lining and papillae

A

Epithelium bacteria

85
Q

What type of environment is in the rumen?

A
  • Anerobic
  • Bacteria that utilise oxygen help
86
Q

Where are fiber digesters most prolific on?

A
  • Forage- based diets
  • Very pH sensitive
  • Do not tolerate high fat concentration in rumen (>5%)
87
Q

What do fiber digesting bacteria primarily produce?

88
Q

What are the primary substrates for fiber digesting bacteria?

A
  • Cellulose
  • Hemi-cellulose
  • Pectin
89
Q

What do fiber digesting bacteria include?

A
  • Ruminococcus flavefacians
  • Ruminococcus albus
  • Bacteriodes succinogens
  • Butyrivibrio fibirisolvens
90
Q

What do fiber digesting bacteria break down?

A

Cellulose and hemi cellulose

91
Q

Does bacteria increase or decrease when fed cellulose rich diet?

92
Q

Is spring grass digestible?

A
  • Yes
  • leaf tissue
    -Sugars
    -less cellulose and hemi cellulose
  • Microbial profiles differ per grass fed
93
Q

What is the normal pH of the rumen?

94
Q

Examples of a dairy cow diet

A
  • Feed 5kg of concentrates ontop of grass, pH drops closer to 6
  • Feeding 12-14kg concentrates to indoor young bulls, pH drops to 5.4-5.5 (almost no cellulose in the diet)
95
Q

What diets are mainly associated with acidosis?

A

Starch based diets

96
Q

What are bacteria sensitive to?

A
  • Lactic acid
  • Prefer a neutral pH
  • Also sensitive to fat
  • 6% DM inclusions of fats
  • Can have a negative impact of this bacteria, particularly where these are poluunsaturated
97
Q

Is fat energy dense?

A
  • Yes
  • A lot of energy in a small quantity of feed
98
Q

What do fiber digesting bacteria primarily produce?

A
  • Acetate
  • Propionate
  • Butyrate
99
Q

Normal VFA proportions in the rumen

A
  • Acetate: 70%
  • Propionate: 20%
  • Butyrate: 10%
    Grass doesn’t contain VFA’s
100
Q

Can VFA proportion be changed with diet?

A
  • Yes
  • With the exception of silage, the feed does not contain VFA’s. They are produced in the rumen
  • Add starch or sugar will change the VFA proportion
  • More propionate, less acetate. Enhances performance
101
Q

Does feeding concentrates enhance performance?

A
  • Yes
  • Provides with more energy
  • More energy dense diet
  • More energy per kg of concentrate than forage
102
Q

What is the most energy dense VFA?

A
  • Butyrate
  • Too much is toxic
103
Q

How many carbons does each VFA have?

A
  • Acetate: 2 carbon atoms
  • Propionate: 3 carbon atoms
  • Butyrate: 4 carbon atoms
104
Q

Another name for fiber digesting bacteria?

A

Cellulolytic Bacteria

105
Q

Another name for Starch and Sugar digesting Bacteria?

A

Amylolytic Bacteria

106
Q

What percentage do starch and sugar digesters make up in the rumens bacterial population?

A

Around 25%

107
Q

What do sugar and starch fermenting bacteria ferment?

A
  • Starch, sugars, peptides and AA’s
  • Sensitive to pH
108
Q

Names of starch and sugar digesting bacteria?

A
  • Bacteriodes ruminocola
  • Bacteriodes amylophilus
  • Selenomonas ruminatium
  • Streptococcus bovis
  • Succinomonas amylolytica
109
Q

What do some amylolytic bacteria produce?

A
  • Lactata
  • Streptococcus bovis
  • Very strong VFA
  • Rapidly drops rumen pH if produced in large quantites
110
Q

When is the risk of S.Bovis high?

A
  • When on high grain diets/ starch rich diets or when there is a high concentration of sugar in the diet
  • Acidosis risk
111
Q

What do amylolytic bacteria produce?

A

Amylase to breakdown amylose

112
Q

What pH do amylolytic bacteria prefer?

A
  • Low pH (close to 6)
113
Q

When do anylolytic bacteria increase?

A
  • When there is an increase of starch and sugar in the diet
  • Smaller with grass
  • Increases with concentrates
  • Base line population in the rumen all the time
  • Increases/decreases depending on quantity of concentrates
114
Q

What acid do Amylolytic bacteria produce?

A
  • Lactic acid
  • Strong acid
  • Rapid impact on pH
115
Q

How can acidosis be prevented?

A

Feeding management

116
Q

Lactate using bacteria name?

A
  • Mehasphaera elsendii
  • Uses lactic acid as a substrate for growth
  • Helps stabilize rumen pH
  • Aids cellulolytic bacteria
  • pH sensitive
117
Q

Common methanogens

A
  • Methanobrevibacter ruminatium
  • Methanomicrobium mobile
118
Q

What does archaea hydrogen using bacteria produce?

A
  • Hydrogen and CO2 as a substrate for growth
  • Equation
119
Q

What is the primary by-produce of methanogens ?

A
  • Methane
  • Produced to stabilise rumen conditions
120
Q

What percentage do methanogens make up in the rumen?

A

less than 3%

121
Q

Are methanogens efficient?

A
  • Yes
  • Utilise 50% of energy used by animal
  • Very good at capturing energy
122
Q

What percentage of energy intake is lost by methane?

123
Q

What do methanogens utilise?

A
  • Hydrogen
  • Use as a growth medium
124
Q

What function do archae hydrogen using bacteria have in the rumen?

A

If there is a large amount of hydrogen, there will be a reduction in pH

125
Q

What is the largest microorganism in the rumen?

A
  • Protozoa
  • Physically the largest
  • 50% of rumen mass
  • Ciliate protozoa
126
Q

Single-cell eukaryote

A
  • Attached to feed particles
  • Long residency time in the rumen
127
Q

Are rumen protozoa fast or slow growing?

A
  • Slow
  • 15+ hours
  • Long time to be replaced
  • Bacteria can multiply in minutes
128
Q

Where are rumen protozoa located within the rumen?

A
  • Usually in the fiber mat
  • Archae often attached to protozoa
  • Easy access to H2
129
Q

What do rumen protozoa eat large amounts of?

A
  • Starch
  • Eats large amounts at one time and can store it in their bodies
  • Can help slow down the production of acids that lower rumen pH
  • This benefits the rumen
130
Q

What is rumen protozoa an important source of?

A

Microbial protein

131
Q

Functions of rumen protozoa?

A
  • Two contradictory functions
    1. Present in large quantites in large fiber and starch diets
132
Q

Relationship between archae and protozoa

A
  • Interspecies transfer of hydrogen-> means that archae will live on/in protozoa
  • Protozoa release hydrogen, archae have a ready source of hydrogen by being close
133
Q

Optimal pH range for cellulose digestion?

134
Q

Optimal pH range for formation of VFA’s

135
Q

Optimal pH range for synthsis of protein

136
Q

Optimal pH range for lactate production?

137
Q

What type of process is fermentation?

A
  • Oxidative process
  • Anaerobic metabolic process in which an organism converts a carbohydrate to an alcohol of an acid
138
Q

Where are VFA’s produced?

139
Q

What are the two phases of fermentation in the rumen?

A
  1. Glycolysis
  2. Fermentation of pyruvate
140
Q

What is broken down during fermentation in the rumen?

A
  • Breakdown of substrates, predominately acids
  • can undergo respiration, anaerobic glycolysis and fermentation
141
Q

Another name for carbohydrates

142
Q

Types of carbohydrates?

A
  • Monosaccharides
  • Disaccharides
  • Oligosaccharides
  • Polysaccharides
143
Q

Monosaccharides

A
  • Simple sugars with multiple OH groups
  • Based on the number of carbons (3,4,5,6)
  • A monosaccharide is a triose, tetrose, pentose or hexose
144
Q

Disaccharide

A

2 monosaccharides covalently linked

145
Q

Oligosaccharides

A

A few monosaccharides covalently linked

146
Q

Polysaccharides

A
  • Polymers consisting of chains of monosaccharide or disaccharide units
147
Q

What is the majority type of carbohydrates in ruminants?

A
  • Polysaccharides
  • Energy stored in carbon bonds
148
Q

What does Pyruvate do?

A
  • Broken down into VFA’s, occasionally lactic acid
  • The more carbons that are present, the more energy that is produced
149
Q

Factors affecting fibre fermentation

A
  1. Rumen pH
  2. Rumen passage rate
  3. Diet digestibility
150
Q

How does rumen pH affect fibre fermentation?

A
  • Homeostatic responses to maintain desired conditions in the rumen
  • Microbial fermentation produces heat in the rumen
    -Fibre digesting microbes like higher pH- neutral
  • When the pH drops, microbes dont act as well
151
Q

How does rumen passage rate affect fiber fermentation?

A

refer to notes

152
Q

How does diet digestibility affect fiber fermentation?

A
  • Not broken down in the rumen
153
Q

If the rate of VFA production higher than the rate of VFA absorption, what happens?

A

pH will decline

154
Q

In diets that are rich in starch/NFC, what happens to VFA’s?

A
  • More will be produced in a short space of time
155
Q

What happens when there is less buffering capacity (saliva)?

A

Lower mastication due to degradability

156
Q

Does a low pH impact carbohydrate fermentation?

A
  • Yes
  • Microbial growth is reduced
  • Energy normally used for the production of microbial protein is instead diverted to maintain a neutral pH in bacterial cells (reduced microbial N flow)
157
Q

What is the flow of digesta in the rumen controlled by?

A

The GI (digestive tract, reticulum and abomasum)

158
Q

Passage rate of complex carbohydrates (high structural fibre content)?

A
  • High structural content
  • Long residency time in the rumen
  • Lower passage rate
159
Q

Passage rate of simple carbohydrates (sugars) ?

A
  • Rapidly broken down in the rumen
  • Small particle size/ soluable
  • Rapid passage rate
160
Q

Why is it important to maintain optimum rumen passage rate?

A
  • To allow time for microbial fermentation and absorption of VFA’s etc to occur
161
Q

Is NDF essential in diets? What percentage?

A
  • Yes
  • 30% of DM by dairy cows shouls be NDF
162
Q

How to obtain a higher passage rate?

A
  • Let the animal feed long enough for VFA absorption
  • Achieved by having a target in the diet
163
Q

What does NDF stand for?

A

Neutral detergent fiber

164
Q

What percentage of DM by dairy cows should be NDF?

165
Q

Does straw slow down or speed up passage rate?

A
  • Slow down
  • Long fibres
166
Q

Degradability definition

A

How rapidly is feedstuff degraded in the rumen

167
Q

Digestibility definition

A

How much of the nutrient consumed (eg NDF) is digested and absorbed in the GI

168
Q

Is protein degradable?

A
  • Yes
  • Usually rapidly degradable
  • Turns into ammonia
169
Q

What happens when ammonia is captured?

A
  • There must be energy avaliable to microbes
170
Q

How can digestibility and degradability be measured?

A
  • In Sacco ( using rumen fistulated animals/ animas with cannulas in the rumen)
  • In vitro (in a lab)
  • NIR (infrared)
171
Q

Negative factors with degradability

A
  • Invasive with animals
  • Time- consuming
  • Costly
172
Q

What measures can indicate digestibility?

A
  • NDF and ADF: fiber density measures
  • DMD = 88.9 - [0.779 X %ADF (on a dry matter basis)]
173
Q

What is the less digestible part of fiber, cellulose and lignin?

174
Q

NDF, ADF and ME of straw?

A
  • 85% NDF
  • 55% ADF
  • 6 - 6.5 ME
175
Q

NDF, ADF and ME of maize meal?

A
  • 10% NDF
  • 3% ADF
  • 13.5 ME
176
Q

NDF, ADF and ME of soya hulls?

A
  • 60% NDF
  • 50% ADF
  • 11.5 ME
177
Q

Functions of molasses

A
  • Adds energy and binds diet together
  • Highly digestible, digestion immediately
  • If given too much, can cause scour ets
178
Q

What happens to straw in the diet?

A
  • Low digestibility
  • Most ends up in dung but takes long time to achieve this
179
Q

What happens to VFA’s, acetic acid, propionic acid and butyric acid when the level of concentrates fed goes up?

A
  • VFA’s go up
  • Acetic acids goes down
  • Propionic acid levels go up
  • Butyric acid levels remain constant
180
Q

What happens when the VFA proportion changes in the diet?

A
  • Rumen pH drops
  • More propionic acid produced
181
Q

What happens to VFA’s when bacteria in the rumen digest carbs to VFA’s?

A
  • Acetate increases in forage diets
  • Propionate increases in starch diets
  • Butyrate is formed from acetate
182
Q

What happens to the rate of VFA production in fiber fermentation?

A
  • Feedstuff ie. maize vs grass silage
  • Rumen pH is low- reduces fiber digestion (6 - 6.2)
  • Forage degradability
183
Q

What is the challenge associated with fibre fermentation?

A

To provide forage which balances rapidly and slowly degradable carbohydrates to maintain rumen function and production

184
Q

Can ruminants change their AA profile in the diet to what they require in their system?

185
Q

Microbial protein synthesis

A
  • Bugs in the rumen synthesis AA’s and then become available to the animal
  • End product of the digestion of bugs by the cow
  • For synthesis, bacteria must have access to nitrogen and energy
186
Q

What happens when there is a lack of synchrony between energy and protein?

A

Protein wastage in the ruminant

187
Q

Is rumen undegradable protein beneficial?

A

Can sometimes be beneficial for some protein to pass through the rumen without being degraded

188
Q

What is the main intermediate compound?

189
Q

Why is it almost impossible to find AA’s in the rumen?

A

They are broken down into ammonia

190
Q

What happens to ammonia in the rumen?

A
  • Some is absorbed and transferred to the liver
  • We don’t want this to happen, ends up being released into the environment
  • Ammonia captured by bacteria to produce microbial protein then travels into the small intestine
191
Q

For protein to be utilised, what firstly needs to happen?

A

Protein needs to be degraded to AA’s

192
Q

What is the main processing centre in the body?

193
Q

What type of biodegradability does microbial protein have?

A

Exceptionally high

194
Q

What percentage of nitrogen is digested in the digestive tract?

195
Q

Where is the second source of P excreted?

A

Faeces
metabolic nitrogen
(These are proteins that were part of the animal eg cells)

196
Q

Is ammonia volatile in the rumen?

197
Q

Why is metabolisable protein important in the diet of ruminants?

A
  • Required to meet the physiological demand of ruminants
  • Growth, lactation and pregnancy
198
Q

Three primary functions of RDP?

A
  1. To meet the RDP requirements of rumen microbes for maximum carbohydrate digestion and maximal microbial protein synthesis
  2. Provide the protein needed for host animal maintenance, growth, optimal health and reproduction with minimal RUP intake
  3. Fulfil the AA requirements of highly productive ruminants using minimal dietary CP
199
Q

What is secreted by rumen bacteria?

A
  • Proteolytic enzymes
  • Degrade RDP to peptides, AA’s and NH3
200
Q

What are deaminated in the rumen?

A
  • BCAA
  • Branches chain VFA/ PDVFA = by-products
  • Iso-butyric, iso-valeric and valeric acid
201
Q

What are essential for growth of cellulolytic bacteria in the rumen?

A
  • Branched chain VFA or protein derived VFA (PDVFA)
  • Vital for efficient fibre digestion and microbial protein synthesis to occur
  • Undersupply of dietary protein= impacted production, DMI etc
202
Q

What is the primary source of protein supplied to the small intestine?

A
  • Microbial synthesis by rumen microbes
  • Accounts for 50-80% of total absorbable protein
203
Q

Microbial protein equation

A

Energy + NH3 = Microbial protein
- Dependant on CHO availability

204
Q

What is combined with carbohydrates to form microbial protein?

205
Q

What are rumen cellulolytic bacterias preference as their N source

206
Q

What happens when CHO supply is limited?

A
  • AA’s are instead deaminated
  • Carbon skeletons fermented to PDVFA
207
Q

Where do ruminats mainly utilise nutrients?

A
  • Tissues
  • But have another metabolic system- microbial metabolism in the rumen
  • The rumen microbial population gets first access to any feed eaten by the cow
  • Therefore, most of the cows absorbed nutrients are the result of microbial fermentation or modification, not what the cow actually eats
208
Q

How is maximum benefit to overall fermentation achieved?

A
  • If the availability of energy and nitrogen are synchronised

Animal Nutrition 2 (2 decks)

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