Nutrition II Flashcards
What is fermentation
A method of feed digestion
Oxidative
how many type of ruminants are there
over 180
capacity of the rumen
80-100 L
What is the rumen lined with
Filiform and Foliate epithelium for increased SA for VFA absorption
Function of Cranial Pillar
Holds digesta away from oesophagus, allows eruction of gases
Appearance of reticulum
honeycomb structure
function of reticulum
controls flow rate of digesta
omasum
filters digesta in folds called laminae and flushed back into rumen for rumination
what protects abomasum
mucus from pepsin and HCLM
Where does the first stage of protein digestion occur ?
abomasum
3 types of rumen microbiota
bacteria, eukaryota, archaea
what % of rumen bacteria bind to feed particles
75%
function of rumen bacteria
Digest starch, Sugars, Lipids, Proteins
2 types of rumen bacteria
Fibre digestion ( Cellulolytic)
Starch & Sugar Digesters( Amalytic)
What % of the rumen do Amylolytic bacteria take up
25%
Fibre digesters work greatest on forage diets but don’t suit high fat diets above what
%
no greater than 5%
Fibre digesters primarily work on what?
Cellulose, Hemicellulose, Pectin
What is an example of a lactate using bacteria in the rumen
Megasphaera elsdenii
What % of the rumen do Protozoa take up
50%
What are the advantages of Rumen Protozoa
Single cell Eukaryote
Long residency time in the rumen
Attach to feed particles
How long does it take rumen protozoa to grow
15+ hrs
location of rumen protozoa
fibre mat of the rumen
How can rumen protozoa benefit the rumen?
They can eat large amounts of starch at one time and store it in their bodies which in turn
slows down the production of acids that lower the PH of the rumen.
optimum pH for:
cellulose digestion
formation of VFA
synthesis of protein
lactate production
cellulose digestion 6-6.8
formation of VFA 6.2-6.6
synthesis of protein 6.3-7.4
lactate production 5.9-6.2
Nitrogen is essential for what
Producing microbial protein in ruminants
How can we reduce N losses from dairy cows
Either by reducing dietary N or increasing N use by rumen microorganisms
What is a solution excess N being produced
Forages with lower concentrations of N and less soluble protein
An example of a structural carbohydrate
lignin
How is degradability of forages measured
In vitro gas production technique or via in sacco nylon bag technique
Wheat and barley straw have a soluble fraction of what
15%
PRG & white clover have a soluble DM of
30-40%
What sort of a process is fermentation
Oxidative process
fermentation
It is a metabolic process in which an animal converts a carbohydrate into an acid or an
alcohol.
What is a major constituent of plant cell walls
Cellulose. Made up of B(1-4) Linkages
What is cellulose starch and sugars broken down into
hexose
What are 3 main factors affecting fibre fermentation
Rumen PH
Diet Digestibility
Rumen Passage rate.
What causes the Ph of the rumen to decline
When VFA absorption is faster than VFA production
What is meant by rumen passage rate
Flow of digesta out of the rumen
What influences Passage rate
Complex CHO - Slow passage rate due to high structural content
Simple CHO - Fast passage rate as the small particles are rapidly broken down in the
rumen.
degradability
Degrading of feedstuff in the rumen
digestibility
How much of the nutrients consumed are absorbed and digested in the G.I (Reticulum &
Abomasum)
What are other methods of measuring digestibility
NDF, ADF and DM
What is the key functions of metabolizable protein
Growth, Lactation, Pregnancy
Two types of Rumen Protein
Rumen Digestible protein
Rumen Degradable Protein
What is the primary source of protein supplied to the S.I by
Microbial protein synthesis accounting for 50-80% of total absorbable protein
What is the purpose of energy systems
Bring together information on energy requirements of animals as well as providing info on the energy supplied by diets.
What energy system is adopted in ireland
French system
What are the two main losses from DE
urine & methane
Losses from DE can be put down to:
Inefficient feed digestion
How is Gross energy measured
bomb calorimetry
What is the typical GE content of most feeds
18-20 Mj of GE/kg DM
What is the formula for digestibility
Digestibility = Feed intake - faeces output / Feed intake
Calculate the following
Cow eats 25KgDM and produces 7.5 kg DM. What is digestibility
0.7
What losses does Metabolizable energy account for?
Losses through urine and gases lost from the rumen
Methane typically makes up what % of GE
8-9%
Methane typically takes up what % of DE
10-11%
Urine typically takes up what % of GE
3-5%
How is NE calculated
ME - HI
How is HI calculated
Indirect calorimetry
What is indirect calorimetry
A method estimating heat production through oxygen consumed, carbon dioxide produced and N in the urine.
Two types of respiration chambers
Open and closed circuits
What is the maintenance requirement for a 600 kg cow
M= 1.4(0.6BW)/100
M=1.4(0.6600)/100
M=5.04 UFL
WHat is the requirement for milk of a cow producing 25kg milk and 3.8% fat
Requirement for milk = 0.44(0.4+0.15FC)
= 0.44(0.4+0.153.8) = 0.43
Per 25kg = 250.43 = 10.75 UFL
What is the formula for 1 kg BW loss
3.5 x BW loss
What is the formula for BW gain
4.5 x BW gain
A loose housed animal will have an increased requirement of what
10%
A Pasture based animal will have an increased requirement of what
20%
Outline the energy requirements for pregnant cows in order of months and UFL
0.9 7 month
1.6 8 months
2.6 9 months
Feed intake is a function of what?
Meal size and meal frequency
What is one of the best indicator of ill health in ruminants
Decrease in DMI
When an animal reaches their rumen capacity it is called
Distension
When Distention occurs the brain detects high levels of what?
High levels of digestion end products in the liver and the animal will stop intake until the concentration decreases
What is the Thermoneutral zone of a dairy cow
Minus 15 degrees to plus 25 Degrees
What are 3 characteristics influencing Ruminant feed intake
Food Factors, Animal factors, Environmental factors
Every 100 kg increase in BW will result in
3KG increase in DMI
Overly fat animals will produce what hormone
Leptin which reduces intake
The 5 Key nutrients in ruminants in order
Air Water Energy Protein Vitamins minerals
5 factors affecting Energy requirements of ruminants
Maintenance Growth Health Lactation Reproduction gestation
What is the most important factor influencing performance
Dry matter intake DMI
What directly controls the amount of energy consumed and available for metabolism
DMI
Sub optimal DMI can result in
Metabolic disease and reduced performance
What % of BW does DMI typically take up in a diet
2-4%
Two important Hormones in feed regulation are what?
Neuroendocrine system and hormonal secretion
What stimulates feeding behaviour
Orexigenic signals
What is inhibits feeding behaviours
Anorexigenic signals
What are examples of Inhibitory signals
Rumen distention
Rumen Osmolality
Gut peptides
Pancreatic hormones
Adipokines
The main characteristics affecting intake in ruminants
Rumination and fermentation of fibrous feeds
Retention time
Rumen capacity
As digestibility of a forage increases so too does intake, due to
faster passage rate
4 key minerals to ensure a ruminant is not deficient in
S P Na Co
What are the main environmental factors affecting feed intake
Heat , Rain , Grazing factors , Temp , Day length , Parasite infestation, ill health
What is the ideal bite size for a dairy cow
0.6 g DM
What is the ideal bite rate for a dairy cow
60/min
What is the target time spent grazing per day by a dairy cow
8-10hrs
What will be a result of excessively hot weather
reduced intake
What will be a result of cold weather
increased intake
What are the main animal factors that can affect intake in ruminants
over fat animals
Very thin animals
Pregnant animals
Physiological status
What is the correct fill units for the following
Dairy cattle
Beef cattle
Sheep
Dairy cattle - LFU
Beef Cattle - CFU
Sheep - SFU
Maintenance takes up what % of energy that goes into a cow
60-80%
What effect will wet grass have on intake
Lower intake as water is filling up the rumen
Higher intake is associated with what
Short fibers
What is PDIMN
Microbial protein that could be synthesised when Nitrogen is limiting
What is PDIME
Microbial protein that could be synthesised when fermentable energy is limiting
Where does the main energy supply for Ruminants come from
Carbohydrates and Fats
What is the max inclusion rate for fats in a ruminant’s diet
No more than 5%
WHat is the results if a diet has more than a 5% fat inclusion rate
Depression in intake
Two types of structural carbohydrates
Cellulose and hemicellulose
What are the end products of digestion
VFA
What are examples of VFA
Acetic, propionic, Butyric
Where are VFA absorbed
Rumen wall
What is meant by physically effective fibre
Ruminants require fibre in a coarse physical form
WHat content should NDF be of dietary dry matter
30% with at least 21% forage
What is a problem with the ME system
ME values are not necessarily related to an animal’s maintenance or production
ME overestimates the available energy of forages relative to concentrates
The dietary CP requirements of cattle are
Minimum >7%
Young /Growing 13-15%
Finishing cattle 11-12%
Lactating dairy cows 14-17%
What is non protein nitrogen
Refers to components such as urea, biuret, and ammonia which are not proteins but can be converted into proteins by microbes in the ruminant stomach
Name 4 common types of forages used in ruminant diets
Grass
Legumes
Herbs
Brassicas
A type of grass very toxic to horses
vetch
What is true about legumes
They are rarely grazed on their own by ruminants bar sheep
Two examples of herbs
Chicory and plantain
What influences nutrient availability
Degradability
Grass silage has what % CP content
~12%
An example of a feed deficient in calcium
cereals
What is the most common cereal used in diets
barley
What is the max recommended inclusion rate of starch in a diet
max 50%
What is the CP content of Barley
10-12%
What is the OMD content of Barley
81-88%
What is the starch content of Wheat
65-70%
WHat is the max recommended inclusion rate of wheat
Max 40%
Wheat contains what
gluten
What is the CP content of wheat
10-16%
What is the max inclusion rate of wheat in sheep diets
max 50%
What are examples of high fibre energy supplements
Molassed beet pulp
Unmolassed beet pulp
Soya hulls
Molasses
Molassed beet pulp is rich in what
digestible cellulose
Molassed beet pulp has sugar content of what
20%
Examples of Cereal by products
Pollard/wheat bran
Maize gluten feed
Maize distillers
Examples of oil seed by products
Palm kernel meal
What is the fibre content of palm kernel meal
80-85%
What is the crude protein content of palm kernel meal
20-25%
Give two examples of protein supplements
Rapeseed meal
Soyabean meal
The fraction of fibre that stimulates chewing activity is called what ?
Physically effective NDF
What effect does physically effective NDF have on the animal
Enhances saliva flow
Increases milk fat levels
Maintains rumen PH
What is net energy primarily used for in ruminants
Production and maintenance
WHat are two main maintenance values
UFL and UFV
What does UFL relate to
Maintenance and production in dairy cows and sheep
WHat does UFV relate to
Maintenance and weight gain in fattening animals
Barley is best fed in what form
Rolled and dried
WHat supplement is essential to balance peNDF in the diet
Wheat
What is pearson’s square
A tool used to calculate energy and protein supply
Why is methane produced
To use up H+ in the rumen of animals
What is a useful role of methane in ruminants
Helps maintain a microbial population
What % of methane come from enteric fermentation
57%
How many more times potent is methane than carbon
28 times more potent
Methane is best described as
A short lived gas
Co2 has a GWP of
1
An example of a gas short lived in the atmosphere and released from the use of
Fertilisers
nitrous oxide
Nitrous oxide is said to have a GW potential of
298
What % of irish water has unsatisfactory or poor quality due to free draining soils
43%
How long does methane live in the atmosphere
12yrs
Examples of nutrient dense products
Milk and meat
Since 1990 and 2017 there has only been a what % increase in methane emissions
1.7%
What is glycolysis
The breakdown of feedstuff into glucose
What is butyrate formed from
acetate
Where more acetate is produced so to is what
methane
What is the MJ/kg of energy provided by methane
55
What % of total microbes does archaebacteria make up
0.5 - 3.0%
What will help reduce CH4
By providing an alternative sink for H2
What is the capacity of the rumen of a cow
100 - 120 Litres
What is the PH of the rumen
5.5-6.5
Mastication accounts for what % of gas released from cows
90-95%
A proven method of reducing methane emissions
Oil inclusion in the diet
How is microbial protein formed
Ammonia + Energy
Main function of the rumen
Carbohydrate digestion
What most accurately describes methane production
Methane production is a function of the animal, the diet and the microbial population in the rumen
Where is most methane excreted by hind gut fermenters
Excreted through the breath from the lungs
What is one management strategy that can help reduce methane
Selection of animals with less of a genetic capacity to produce methane
Where are protozoa found
The fibre mat of the rumen
The removal of protozoa is responsible for
Significant proportion of methane production
Two minerals that have the potential to reduce methane emissions
fats and oils
The use of linseed oil has found what
A methane per day production decrease of 17%
Methane reduction per kg milk solids of 20%
What is ether extract
Total crude oil content of a forage
To reduce methane we can
Breed , Feed and supplement
WHat VFAs are involved in the production of methane
Acetate, Butyrate, Propionate.
What VFA is least energy dense
acetate
What VFA is most energy dense
butyrate
WHy is methane produced in the rumen
The rumen is a large energy making mechanism for certain groups of microbes which live in the rumen. Methane is formed as aby product of VFA fermentation by
What is the formation of methane known as
Methanogenesis
What % of methane is released as a result of belching
90%
What % of methane is released anally
5-10%
Methane accounts for what % of energy intake in animals
10-12%
A high concentrate diet will lower emissions in comparison to
a grass based diet
What are the advantages of including fat in a diet of a cow
Increases energy & reduces methane production
WHat is the max inclusion rate of fat in a diet
max 6%
What are the consequences of including fat above 6%
Inhibits CHO digestion
For every 1% of fat given to a cow, what % decrease in methane yield is observed
5-6%
Plant oils all have
High concentrations of polyunsaturated fats
Why is fat not included at high rates in diets
It has the ability to inhibit CHO digestion
Linseed oil has shown what % reduction in methane
17% daily
What is defaunation
The inhibition or removal of methanogens & protozoa using plant oils.
Seaweed has the ability to increase ADG by
22%
Seaweed can reduce enteric fermentation by what %
50%
What % of irish rivers have unsatisfactory nitrate concentrations
43%
What % of ireland’s ammonia emissions does agriculture account for
99%
Agriculture accounts for what % of total emissions
37.5%
Enteric fermentation accounts for what %
56%
What are some of the requirements for derogation 2022
Low emission spreading after 15th April
Clover inclusion in reseeds
Crude protein limit at 16% from 1st april to 15th september
Commonage fert limit 50 kg N ha
Grass measuring and nutrient management plan
Protein is available in two forms. What are they
Rumen degradable protein
Rumen undegradable protein
RDP is degraded to what
ammonia
What creates microbial protein
Energy + Ammonia
True protein can be regarded as?
Microbial protein
Give the three functional groups
Grass
Legumes
Herbs
What is Multispecies forages
Forages that contain 2 or more plant species from at least two functional groups
WHat are some of the most common types of legumes
White clover
Red clover
Vetch
What are some of the benefits of Multispecies swards
High Nutritive value
Increased animal performance
Increased summer growth rates
Reduced chemical N use
Increased biodiversity
