The Ruminant (1) Flashcards
(208 cards)
1
Q
How many stomachs does a cow have?
A
4
2
Q
At what part of the tract does microbial digestion take place?
A
The beginning
3
Q
What happens once starch enters the rumen?
A
It will be digested by microbes
4
Q
What are all carbohydrates broken down into?
A
Glucose
5
Q
What is the primary monosaccharide?
A
Glucose
6
Q
Is glucose easy to break down?
A
yes, very
7
Q
Pyruvate
A
Quickly broken down and utilised by the the rumen into VFA’s
8
Q
What are the main VFA’s ?
A
Acetate, propionate and butyric
9
Q
What are the main waste products from a ruminant?
A
CO2 and methane
10
Q
What is produced when carbs are digested in the rumen?
A
Production of Acetate, Propionate and Butyric
11
Q
What is only sometimes produced in the rumen?
A
Lactate
12
Q
What happens when lactate builds up?
A
Acidosis
13
Q
Will all carbs that enter the rumen digested in the rumen?
A
No
14
Q
What does digestibility tell us?
A
How much feed is digested as it passes through
15
Q
Digestibility of silage?
A
70%
16
Q
What happens when cellulose is passed through the rumen undigested?
A
It has a very little chance of being digested
17
Q
What happens when maize passes through the rumen?
A
Becomes available to be digested in the large intestine
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
19
Q
What is the main source of energy?
A
VFA’s
20
Q
What is a ruminant?
A
Has the ability to use fermentation as a method of feed digestion
21
Q
Ruminants have a symbiotic relationship with what?
A
Microorganisms
22
Q
What is the rumen a habitat for?
A
Growth
23
Q
What are microbes?
A
Nutrients that would otherwise be unavailable
24
Q
How many types of ruminants are there?
A
Over 180
25
What types of ruminants are there?
- Concentrate selectors
- Intermediate types
- Grass/roughage eaters
26
Concentrate Selectors
- Don't have large rumen
- Eat small meals regularly
- Eat the most nutritious part
27
Intermediate types
- 8 hours grazing
- 8 hours ruminating
- 8 hours of either
28
Human edible protein output-input ratio for sheep and goats
- 25.5:1 return
- 24.5 gram of human edible protein output for 1 gram of protein
29
Human edible protein output-input ratio for cattle
- 15:1 return
- 15 grams of human edible protein output for 1 gram of protein
30
What part in the true stomach?
Abomasum
31
What stomach squeezes out water?
Omasum
32
What stomach is the 'reseeding jar'?
Reticulum
33
Functions of the rumen?
1. Storage
2. Structure of carbohydrates
3. Synthesis of microbial protein
4. Synthesis of essential micronutrients such as Vitamin B
34
Ruminant GI has 4 compartments
1. Storage
2. Mixes food with microbes
3. Reduces particle size
4. Eliminates gases and regulates flow of digesta to gut
35
Volume of rumen
80-100 L
36
What is the rumen lined with?
- Filiform and foliate epithelium layers
- Increased SA for VFA absorption
37
Rumen Pillars
- Contractions force digesta across pillars and mixes it
- Inoculates digesta with MO
- Transfer of VFA to papillae
38
Cranial pillar
- Holds digesta away from the oesophagus
- Allows new food to enter the rumen(no physical)
39
Why is it important to leave space for gases to be released in the rumen?
As if they are not released, there will be a build up of gases and this may cause bloat
40
What is the first compartment that food travels into from the oesophagus?
The reticulum
41
What does the reticulum hold?
-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
42
What structure is on the epithelium of the reticulum?
honeycomb
43
Why does the reticulum have an essential role in rumination?
Large particles are forced back into oesophagus and particle size is reduced
44
What does ruminants convert non-human edible carbohydrates into?
Human available nutrients
45
What do ruminants and their microbiome have the capacity to create?
- Protein and synthesis other essential nutrients
46
What is required by microbes in the rumen to synthesis vitamin B12?
Cobalt
47
What do microbes utilise?
Protein for growth
48
Omasum structure
- Epithelium arranged in folds called laminae
- These filter digesta
49
What happens when the laminae contract?
- 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
50
Omasum shape
- Spherical
- Size of a football
- Muscular folds of tissue inside
51
Function of papillae
- Absorption
- Removes moisture from digesta as it moves down the digestive tract
52
Mineral leftover in the omasum
Reduced DM content
53
What does the omasum absorb?
Most minerals that aren't absorbed in the rumen
54
What does the omasum act as a buffer between?
The rumen and the abomasum
55
Is the gastric stomach low or high pH
Low
56
What is the only stomach with secretions
- Abomasum
- Protected by mucous from pepsin and HCl
- Only begins to take place in the abomasum
57
what stage is protein digestion in the abomasum
- The first
- Continued in the small intestine
58
What does the abomasum act as a buffer between?
- The high rumen pH and the low pH in the abomasum
59
What happens when there is a decrease in pH in the abomasum
Acidosis
60
What happens when there is an increase in pH in the abomasum
Diarrhea
61
What happens when acidosis gets into the blood
The animal dies
62
What does the mucous in the abomasum do?
Protects the lining of the stomach from HCl and from protein digesting enzymes
63
Microbial Protein in the Abomasum
-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
64
For microbial protein to be utilised in the abomasum, what must happen?
Bacteria must be killed
65
What is the small intestine of a ruminant compared to?
The small intestine of a monogastric
66
What does the small and large intestine contain?
- Secretions from the pancreas and liver
- Enzymatic digestion of protein, fats, sugars and starch
67
Where is water mainly absorbed?
Large intestine
68
What percentage fermentation takes place in the large intestine?
- <10-15%
- Some fermentation of carbohydrates, can be important in some cases
69
What happens when cows reach their peak fiber intake?
- The fiber is not digested in the rumen but instead in the small and large intestine
70
Is fermentation in the large intestine as effective as in the rumen?
No
71
Can animals utilise microbial protein in the small intestine?
- No
- They dont have a chance to
72
Where is the next stop after the intestines?
Faeces
73
What are the simple organisms that are the foundations of life?
Bacteria
74
Where have microbiomes never been cultured?
- Outside of the rumen
- The more we learn, the less we know
75
What do we want microbiomes to do?
Reduce the amount of methane being produced
76
What are microbiome very resistance to?
Change
77
What is bacteria needed for
- To break down grass different to digesting concentrates
78
How long does it take for microbiome to chance?
- 3-4 weeks
- Resilient
- Plastic identity
- Always springs back
79
What is rumen fluid dense in?
Bacteria
80
What is bacteria essential for?
Feed formation
81
What percentage of bacteria is bound to feed particles?
75%
82
What doe bacteria digest?
Sugar, starch, lipids, protein
83
How many bacteria per ml of rumen fluid?
1 billion
84
What bacteria are stuck to the lining and papillae
Epithelium bacteria
85
What type of environment is in the rumen?
- Anerobic
- Bacteria that utilise oxygen help
86
Where are fiber digesters most prolific on?
- Forage- based diets
- Very pH sensitive
- Do not tolerate high fat concentration in rumen (>5%)
87
What do fiber digesting bacteria primarily produce?
Acetate
88
What are the primary substrates for fiber digesting bacteria?
- Cellulose
- Hemi-cellulose
- Pectin
89
What do fiber digesting bacteria include?
- Ruminococcus flavefacians
- Ruminococcus albus
- Bacteriodes succinogens
- Butyrivibrio fibirisolvens
90
What do fiber digesting bacteria break down?
Cellulose and hemi cellulose
91
Does bacteria increase or decrease when fed cellulose rich diet?
Increase
92
Is spring grass digestible?
- Yes
- leaf tissue
-Sugars
-less cellulose and hemi cellulose
- Microbial profiles differ per grass fed
93
What is the normal pH of the rumen?
6.4 - 6.7
94
Examples of a dairy cow diet
- 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
What diets are mainly associated with acidosis?
Starch based diets
96
What are bacteria sensitive to?
- 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
Is fat energy dense?
- Yes
- A lot of energy in a small quantity of feed
98
What do fiber digesting bacteria primarily produce?
- Acetate
- Propionate
- Butyrate
99
Normal VFA proportions in the rumen
- Acetate: 70%
- Propionate: 20%
- Butyrate: 10%
Grass doesn't contain VFA's
100
Can VFA proportion be changed with diet?
- 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
Does feeding concentrates enhance performance?
- Yes
- Provides with more energy
- More energy dense diet
- More energy per kg of concentrate than forage
102
What is the most energy dense VFA?
- Butyrate
- Too much is toxic
103
How many carbons does each VFA have?
- Acetate: 2 carbon atoms
- Propionate: 3 carbon atoms
- Butyrate: 4 carbon atoms
104
Another name for fiber digesting bacteria?
Cellulolytic Bacteria
105
Another name for Starch and Sugar digesting Bacteria?
Amylolytic Bacteria
106
What percentage do starch and sugar digesters make up in the rumens bacterial population?
Around 25%
107
What do sugar and starch fermenting bacteria ferment?
- Starch, sugars, peptides and AA's
- Sensitive to pH
108
Names of starch and sugar digesting bacteria?
- Bacteriodes ruminocola
- Bacteriodes amylophilus
- Selenomonas ruminatium
- Streptococcus bovis
- Succinomonas amylolytica
109
What do some amylolytic bacteria produce?
- Lactata
- Streptococcus bovis
- Very strong VFA
- Rapidly drops rumen pH if produced in large quantites
110
When is the risk of S.Bovis high?
- When on high grain diets/ starch rich diets or when there is a high concentration of sugar in the diet
- Acidosis risk
111
What do amylolytic bacteria produce?
Amylase to breakdown amylose
112
What pH do amylolytic bacteria prefer?
- Low pH (close to 6)
113
When do anylolytic bacteria increase?
- 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
What acid do Amylolytic bacteria produce?
- Lactic acid
- Strong acid
- Rapid impact on pH
115
How can acidosis be prevented?
Feeding management
116
Lactate using bacteria name?
- Mehasphaera elsendii
- Uses lactic acid as a substrate for growth
- Helps stabilize rumen pH
- Aids cellulolytic bacteria
- pH sensitive
117
Common methanogens
- Methanobrevibacter ruminatium
- Methanomicrobium mobile
118
What does archaea hydrogen using bacteria produce?
- Hydrogen and CO2 as a substrate for growth
- Equation
119
What is the primary by-produce of methanogens ?
- Methane
- Produced to stabilise rumen conditions
120
What percentage do methanogens make up in the rumen?
less than 3%
121
Are methanogens efficient?
- Yes
- Utilise 50% of energy used by animal
- Very good at capturing energy
122
What percentage of energy intake is lost by methane?
15%
123
What do methanogens utilise?
- Hydrogen
- Use as a growth medium
124
What function do archae hydrogen using bacteria have in the rumen?
If there is a large amount of hydrogen, there will be a reduction in pH
125
What is the largest microorganism in the rumen?
- Protozoa
- Physically the largest
- 50% of rumen mass
- Ciliate protozoa
126
Single-cell eukaryote
- Attached to feed particles
- Long residency time in the rumen
127
Are rumen protozoa fast or slow growing?
- Slow
- 15+ hours
- Long time to be replaced
- Bacteria can multiply in minutes
128
Where are rumen protozoa located within the rumen?
- Usually in the fiber mat
- Archae often attached to protozoa
- Easy access to H2
129
What do rumen protozoa eat large amounts of?
- 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
What is rumen protozoa an important source of?
Microbial protein
131
Functions of rumen protozoa?
- Two contradictory functions
1. Present in large quantites in large fiber and starch diets
132
Relationship between archae and protozoa
- 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
Optimal pH range for cellulose digestion?
6 - 6.8
134
Optimal pH range for formation of VFA's
6.2 - 6.6
135
Optimal pH range for synthsis of protein
6.3 - 7.4
136
Optimal pH range for lactate production?
5.9 - 6.2
137
What type of process is fermentation?
- Oxidative process
- Anaerobic metabolic process in which an organism converts a carbohydrate to an alcohol of an acid
138
Where are VFA's produced?
Rumen
139
What are the two phases of fermentation in the rumen?
1. Glycolysis
2. Fermentation of pyruvate
140
What is broken down during fermentation in the rumen?
- Breakdown of substrates, predominately acids
- can undergo respiration, anaerobic glycolysis and fermentation
141
Another name for carbohydrates
Glycans
142
Types of carbohydrates?
- Monosaccharides
- Disaccharides
- Oligosaccharides
- Polysaccharides
143
Monosaccharides
- 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
Disaccharide
2 monosaccharides covalently linked
145
Oligosaccharides
A few monosaccharides covalently linked
146
Polysaccharides
- Polymers consisting of chains of monosaccharide or disaccharide units
147
What is the majority type of carbohydrates in ruminants?
- Polysaccharides
- Energy stored in carbon bonds
148
What does Pyruvate do?
- Broken down into VFA's, occasionally lactic acid
- The more carbons that are present, the more energy that is produced
149
Factors affecting fibre fermentation
1. Rumen pH
2. Rumen passage rate
3. Diet digestibility
150
How does rumen pH affect fibre fermentation?
- 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
How does rumen passage rate affect fiber fermentation?
refer to notes
152
How does diet digestibility affect fiber fermentation?
- Not broken down in the rumen
153
If the rate of VFA production higher than the rate of VFA absorption, what happens?
pH will decline
154
In diets that are rich in starch/NFC, what happens to VFA's?
- More will be produced in a short space of time
155
What happens when there is less buffering capacity (saliva)?
Lower mastication due to degradability
156
Does a low pH impact carbohydrate fermentation?
- 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
What is the flow of digesta in the rumen controlled by?
The GI (digestive tract, reticulum and abomasum)
158
Passage rate of complex carbohydrates (high structural fibre content)?
- High structural content
- Long residency time in the rumen
- Lower passage rate
159
Passage rate of simple carbohydrates (sugars) ?
- Rapidly broken down in the rumen
- Small particle size/ soluable
- Rapid passage rate
160
Why is it important to maintain optimum rumen passage rate?
- To allow time for microbial fermentation and absorption of VFA's etc to occur
161
Is NDF essential in diets? What percentage?
- Yes
- 30% of DM by dairy cows shouls be NDF
162
How to obtain a higher passage rate?
- Let the animal feed long enough for VFA absorption
- Achieved by having a target in the diet
163
What does NDF stand for?
Neutral detergent fiber
164
What percentage of DM by dairy cows should be NDF?
30%
165
Does straw slow down or speed up passage rate?
- Slow down
- Long fibres
166
Degradability definition
How rapidly is feedstuff degraded in the rumen
167
Digestibility definition
How much of the nutrient consumed (eg NDF) is digested and absorbed in the GI
168
Is protein degradable?
- Yes
- Usually rapidly degradable
- Turns into ammonia
169
What happens when ammonia is captured?
- There must be energy avaliable to microbes
170
How can digestibility and degradability be measured?
- In Sacco ( using rumen fistulated animals/ animas with cannulas in the rumen)
- In vitro (in a lab)
- NIR (infrared)
171
Negative factors with degradability
- Invasive with animals
- Time- consuming
- Costly
172
What measures can indicate digestibility?
- NDF and ADF: fiber density measures
- DMD = 88.9 - [0.779 X %ADF (on a dry matter basis)]
173
What is the less digestible part of fiber, cellulose and lignin?
ADF
174
NDF, ADF and ME of straw?
- 85% NDF
- 55% ADF
- 6 - 6.5 ME
175
NDF, ADF and ME of maize meal?
- 10% NDF
- 3% ADF
- 13.5 ME
176
NDF, ADF and ME of soya hulls?
- 60% NDF
- 50% ADF
- 11.5 ME
177
Functions of molasses
- Adds energy and binds diet together
- Highly digestible, digestion immediately
- If given too much, can cause scour ets
178
What happens to straw in the diet?
- Low digestibility
- Most ends up in dung but takes long time to achieve this
179
What happens to VFA's, acetic acid, propionic acid and butyric acid when the level of concentrates fed goes up?
- VFA's go up
- Acetic acids goes down
- Propionic acid levels go up
- Butyric acid levels remain constant
180
What happens when the VFA proportion changes in the diet?
- Rumen pH drops
- More propionic acid produced
181
What happens to VFA's when bacteria in the rumen digest carbs to VFA's?
- Acetate increases in forage diets
- Propionate increases in starch diets
- Butyrate is formed from acetate
182
What happens to the rate of VFA production in fiber fermentation?
- Feedstuff ie. maize vs grass silage
- Rumen pH is low- reduces fiber digestion (6 - 6.2)
- Forage degradability
183
What is the challenge associated with fibre fermentation?
To provide forage which balances rapidly and slowly degradable carbohydrates to maintain rumen function and production
184
Can ruminants change their AA profile in the diet to what they require in their system?
Yes
185
Microbial protein synthesis
- 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
What happens when there is a lack of synchrony between energy and protein?
Protein wastage in the ruminant
187
Is rumen undegradable protein beneficial?
Can sometimes be beneficial for some protein to pass through the rumen without being degraded
188
What is the main intermediate compound?
Pyruvate
189
Why is it almost impossible to find AA's in the rumen?
They are broken down into ammonia
190
What happens to ammonia in the rumen?
- 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
For protein to be utilised, what firstly needs to happen?
Protein needs to be degraded to AA's
192
What is the main processing centre in the body?
The liver
193
What type of biodegradability does microbial protein have?
Exceptionally high
194
What percentage of nitrogen is digested in the digestive tract?
80-90%
195
Where is the second source of P excreted?
Faeces
metabolic nitrogen
(These are proteins that were part of the animal eg cells)
196
Is ammonia volatile in the rumen?
Yes, very
197
Why is metabolisable protein important in the diet of ruminants?
- Required to meet the physiological demand of ruminants
- Growth, lactation and pregnancy
198
Three primary functions of RDP?
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
What is secreted by rumen bacteria?
- Proteolytic enzymes
- Degrade RDP to peptides, AA's and NH3
200
What are deaminated in the rumen?
- BCAA
- Branches chain VFA/ PDVFA = by-products
- Iso-butyric, iso-valeric and valeric acid
201
What are essential for growth of cellulolytic bacteria in the rumen?
- 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
What is the primary source of protein supplied to the small intestine?
- Microbial synthesis by rumen microbes
- Accounts for 50-80% of total absorbable protein
203
Microbial protein equation
Energy + NH3 = Microbial protein
- Dependant on CHO availability
204
What is combined with carbohydrates to form microbial protein?
NH3
205
What are rumen cellulolytic bacterias preference as their N source
NH3
206
What happens when CHO supply is limited?
- AA's are instead deaminated
- Carbon skeletons fermented to PDVFA
207
Where do ruminats mainly utilise nutrients?
- 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
How is maximum benefit to overall fermentation achieved?
- If the availability of energy and nitrogen are synchronised
