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GFP :0 > W9- Lecture 26 &27 - Silage > Flashcards

W9- Lecture 26 &27 - Silage Flashcards

1
Q

for how long has Silage has been used to conserve feedstuffs

A

more than 3000 years

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2
Q

what is the most used method for conserving ruminant feed

A

silage

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3
Q

what is the Largest harvested Ag crop in the world

A

silage

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4
Q

how much of grassland is used in western europe for silage

A

10 million ha of grassland
- 25% of which is baled

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5
Q

what is silage

A

Silage is the material produced by the controlled fermentation of a crop of high moisture content

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6
Q

how are forage crops preserved

A

fermentation

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7
Q

what % of all farms make silage

A

Over 85% of all farms making silage
– Beef systems 24-38% feed budget
– Dairy 20-25% feed budget

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8
Q

advantages of Silage vs Hay (4)

A
  • less weather dependent – flexibility
  • Reduced storage costs
  • Reduced field losses – particularly with leguminous crops
  • more feeding crops
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9
Q

disadvantages of Silage vs Hay (3)

A
  • Polyethylene - additional cost and must be disposed of correctly
  • Silage quality is highly dependent on
    maintaining an anaerobic environment
  • greater transport costs per tonne of DM
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10
Q

Dry matter yield – effect on silage cost

  • Cost €/ t DM silage
A

3 t/ha - €240
4 t/ha - € 182
5t/ha - € 147
6t/ha - €124
7t/ha - €107

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11
Q

Dry matter yield – effect on silage cost

Relative cost per t DM grown

A

3 t/ha - € 1.63
4 t/ha - €1.24
5 t/ha - €1.00
6 t/ha - €0.84
7 t/ha - €0.73

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12
Q

DMD % – effect on beef cattle weight gain Teagasc, 2016

A

75% DMD
- harvest date: 20 May
- Silage t DM/ ha: 4.6
- Intake kg/day: 9.0
- Live weight gain kg/ day: 0.83

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13
Q

what happens to concentrates when DMD increases

A

concentrates/cow/day decreases

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14
Q

silage DM yield

A

increase yield = reduced costs

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15
Q

silage digestibility

A

increase yield = reduce digestibility

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16
Q

animal performance

A

reduced digestibility = reduced LWG or yield

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17
Q

Planning a grass silage strategy (8)

A
  1. Reduced concentrate supplementation
  2. Improved milk solids yield
  3. Improve cow/ ewe condition at calving/ lambing
  4. Better herd/ flock fertility
  5. Replacement heifers at target weight
  6. Improved daily gain
  7. Shorter finishing period
  8. Higher annual grass yield
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18
Q

what are the objectives of planning a grass silage strategy (3)

A
  1. high tonnage/ha
  2. well preserved palatable feed
  3. required DMD
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19
Q

what is the target silage DMD for different classes of stock

  • Fresh Autumn- Calving dairy cows
  • Spring calving cows in milk/ Finishing cattle
  • Dairy young stock/ growing cattle
  • Dry dairy cow - poor BCS / suckler cow
  • Dry dairy cow good BCS
  • Dry suckler cows
A
  • Fresh Autumn- Calving dairy cows: 75+
  • Spring calving cows in milk/ Finishing cattle: 74
  • Dairy young stock/ growing cattle: 72
  • Dry dairy cow - poor BCS / suckler cow: 70
  • Dry dairy cow good BCS: 68
  • Dry suckler cows: 66
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20
Q

what are the 5 steps for planning your grass silage strategy

A

Step 1
➢Define the highest quality silage type required on the farm first

Step 2
➢Estimate the quantity of this silage quality needed

Step 3
➢Calculate area of first (and subsequent) cuts required to
produce this silage

Step 4
➢Mark this area on the farm map and set the target cutting date(s)

Step 5
➢Manage the remaining area to produce silage of standard quality

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21
Q

what is the definition of ensiling

A

Ensiling: ability of the forage to preserve well (fermentation) and not suffer high losses in yield and nutritive value during storage

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22
Q

what is forage preservation based on

A

Forage preservation based on spontaneous lactic acid fermentation under anaerobic conditions

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23
Q

what ferment the WSC in the crop and to what?

A

Epiphytic LAB ferment the WSC in the crop to lactic acid and acetic acid

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24
Q

what happens pH in the ensiling process

A

pH decreases and spoilage organisms are inhibited

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25
Q

what are the 4 phases of ensiling process ***

A

Phase 1: aerobic phase
Phase 2: fermentation phase
Phase 3: stable phase
Phase 4: feed-out phase

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26
Q

Phase 1 : aerobic phase (4)

A
  • From when the grass is cut in the field to when it is baled or pitted in a silo
  • O2 present is respired by plant material, facultative aerobes and aerobic m/o’s
  • Usually lasts only a few hours
  • Enzymes, proteases and carbohydrases will be active during this period
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27
Q

what happens to O2 in phase 1

A

O2 present is respired by plant material, facultative aerobes and aerobic m/o’s

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28
Q

how long does phase 1 last

A

only a few hours

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29
Q

what are active during phase 1: aerobic phase

A

Enzymes, proteases and carbohydrases will be active during this period

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30
Q

Phase 2: fermentation phase (4)

A
  • Starts when the silage becomes anaerobic
  • Lasts a few days to a few weeks (BC)
  • If fermentation is successful LAB develop
  • pH decreases to 3.8 – 5.0 depending on DM
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31
Q

when does phase 2 : fermentation phase start

A

Starts when the silage becomes anaerobic

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32
Q

how long does phase 2 : fermentation phase last for

A

Lasts a few days to a few weeks (BC - buffering capacity)

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33
Q

what happens in phase 2 : fermentation phase if fermentation successful

A

If fermentation is successful LAB (lactic acid bacteria) develop

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34
Q

what is the pH of silage in phase 2: fermentation process

A

pH decreases to 3.8 – 5.0 depending on DM

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35
Q

Phase 3: stable phase (3)

A
  • Relatively inactive period provided air is excluded
  • Bacteria decrease in number
  • Some remain inactive or as spores
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36
Q

which phase is relatively inactive

A

phase 3: stable phase
- Relatively inactive period provided air is excluded

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37
Q

Phase 4: the Feed-out Phase(3)

A
  • Begins as soon as the silage gets exposed to air
  • Broken into 2 phases
  • Degradation of preserving organic acids
  • Rise in pH and activity of spoilage organisms such as bacilli, moulds and enterobacteria
  • Occurs in almost all silages but is dependent on the
    number and activity of spoilage m/o’s
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38
Q

when does phase 4: feed out phase begin

A

Begins as soon as the silage gets exposed to air

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39
Q

how many phases is phase 4: feed out phase broken into

A

2

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40
Q

what are the two phases of phase 4 : feed pout phase

A
  • Degradation of preserving organic acids
  • Rise in pH and activity of spoilage organisms such as bacilli, moulds and enterobacteria
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41
Q

does phase 4: feed out phase occur in all silages

A

Occurs in almost all silages but is dependent on the number and activity of spoilage m/o’s

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42
Q

Ensiling: Primary Fermentation

A

reduction in pH:
– DM
– Fermentable substrate (WSC)
– Buffering capacity (BC)
– Microorganisms present on the crop at ensiling

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43
Q

when is WSC increased

A

WSC is increased when the crop is harvested at a high DM content

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44
Q

what do undesirable bacteria prefer

A

wetter crops

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45
Q

how can increase DM can be achieved by

A
  • delaying harvest
    – wilting
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46
Q

what is optimum DM

A

25-30% DM

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47
Q

how do crops lose water

A

through the stomata

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48
Q

what happens to the stomata after mowing

A

After mowing stomata close and the cuticle limits the rate of water loss from the plant

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49
Q

what helps to accelerate the loss of water

A

disruption of the cuticle

50
Q

what is this called
- After mowing stomata close and the cuticle limits the rate of water loss from the plant
- Disruption of the cuticle helps to accelerate the loss of water

A

conditioning

51
Q

what are the primary fermentable substrate in temperate grasses

A

– Glucose
– Fructose
– Sucrose
– Fructans

52
Q

Values are a product of water and WSC contents in the grass

A

(g/L aqueous extract)

53
Q

what is the difference between AM vs PM cutting

A

PM cutting is the preferred option

54
Q

when do WSC increase

A

increase WSC with afternoon cutting

55
Q

PM cutting

A
  • PM cutting is the preferred option.
  • increase WSC with afternoon cutting.
  • Better fermentation characteristics.
  • Less fibrous components.
  • Increased DMI, milk solids production, and nitrogen use efficiency (NUE)
56
Q

what effect do increasing LIGHT INTENSITY have on DM and WSC

A

Increasing light intensity increases DM and WSC

57
Q

What effect does increasing TEMP have on DM and WSC

A

Increasing temperature increases DM and reduces WSC

58
Q

what effect does increase Water supply have on DM & WSC

A

Increasing water supply reduces DM and WSC

59
Q

What is buffering capacity (BC)

A

The equivalents of acid per unit DM required to lower crop pH from 6 to 4

60
Q

What is the typical BC in grass range from

A

250 to 350 mEq/kg DM

61
Q

how is BC measured

A

mEq/kg DM

62
Q

when is BC higher /lower

A

BC is
- higher in legumes
- lower in maize than grass

63
Q

Microorganisms - Epiphytic m/o’s

A
  • Pseudomonads
  • Enterobacteria
  • Actinomycetes
  • Filamentous fungi
  • Yeasts
  • Clostridia spores
  • Acetic acid bacteria
  • Homofermentative lactic acid bacteria
  • Heterofermentative lactic acid bacteria
  • Propionic acid bacteria
64
Q

what is homofermentative bacteria

A

Homofermentative – ferment 1 mole of glucose or fructose to 2 moles of lactic acid

65
Q

what is heterofermentative bacteria

A

Heterofermentative – produce lactic acid plus acetic acid, ethanol or mannitol

66
Q

what are most lactic acid bacteria associated with silage

A

Most LAB associated with silage are capable of fermenting sucrose, hexose’s and pentoses

67
Q

what does clostridia inhibit

A

Clostridia – inhibited growth in the presence of oxygen, acidic pH, low temp or low water activity

68
Q

what does wet silage result in

A

poor fermentation

69
Q

what does Saccharolytic clostridia ferment

A

sugars and LA to produce butyric acid

70
Q

what does Proteolytic clostridia ferment (undesirable microorganism)

A

amino acids producing amines and ammonia (undesirable microorganism)

71
Q

what does enterobacteria spp ferment

A

Ferment carbohydrates to short chain organic acids – acetic acid, ethanol, hydrogen

72
Q

what sort of activity has Enterobacteria spp

A

weak proteolytic activity

73
Q

what does Enterobacteria spp produce

A

produce ammonia and nitrous oxide

74
Q

what does Enterobacteria spp increase but also decrease

A

May increase early in ensilage but decrease rapidly with declining pH

75
Q

Fermentation equations

A

Enterobacteria or coliform
- Glucose + 3ADP + P Acetate + Ethanol +2CO2 + 2H2 + 3ATP + 2H2O

76
Q

fermentation equation - yeast

A

Yeasts
Glucose + 2ADP + 2P 2 Ethanol +2CO2 + 2ATP

77
Q

fermentation equation - Homofermentative LAB

A

Glucose or Fructose + 2ADP + 2P 2 Lactate + 2ATP + 2H2O

78
Q

Fermentation equations- Heterofermentative LAB

A

Glucose + ADP + P Lactate + Ethanol +CO2 + ATP + H2O

3 Fructose + 2ATP + 2P Lactate + Acetate + Mannitol + CO2 + 2ATP + H2O

79
Q

fermentation equation: clostridia

A

2 Lactate + ADP + P Butyrate + 2CO2 + 2 H2 + ATP + 2H2O

80
Q

definition of additives

A

Additives are designed to ensure that the ensiling process stays within predictable boundaries, to promote a rapid lactic acid fermentation, to reduce losses during storage,
and to improve the feeding value of the stored product

81
Q

what is the aim to achieve when related to additives

A

Aim to achieve a low and stable pH as quickly as possible with LA the primary fermentation product

82
Q

what can additives improve

A

the fermentation quality of silage

83
Q

additive types (7)

A
  • Acid based additives
  • Sugar based additives
  • Enzymes
  • Enzyme/salt mixtures
  • Salt mixtures
  • Inoculants
  • Absorbent
84
Q

3 classes of additive

A
  1. Fermentation promoters/stimulants
  2. Fermentation inhibitors
  3. ‘Shelf-life’ enhancers
85
Q

what does Fermentation
promoters/stimulants provide

A

Provide/produce extra fermentable substrate to/from the crop

  • must have sufficient WSC
86
Q

examples of Fermentation
promoters/stimulants

A

Examples:
➢Sugar based compounds e.g. molasses
➢Enzymes
➢Inoculants

87
Q

2 main enzymes

A

Cellulases and hemicellulases

88
Q

why are enzymes used instead of sugars

A

Used instead of sugars to generate extra substrate by breaking down cellulose and hemi-cellulose

89
Q

what are enzymes used with

A

Used with crops of low ensilability esp. low WSC

90
Q

what are inoculants based on

A

Based on Lactobacillus plantarum

91
Q

when are inoculants effective

A

Only effective when there is adequate WSC

92
Q

what should inoculants outnumber

A

Inoculants should outnumber the native bacteria 10:1 (add 106 CFU/g)

93
Q

what do inoculants produce

A

a more rapid pH decline

94
Q

what do fermentation inhibitors do

A

Restrict the fermentation and prevent the development of undesirable bacteria

  • Reduces pH as the crop enters the silo
95
Q

examples of fermentation inhibitors

A

Examples:
➢Acids
- formic acid and sulphuric acid
➢Acid salts
- calcium formate and sodium nitrate

96
Q

what do shelf life enhancers reduce

A

Reduces the aerobic spoilage and therefore increase shelf life once it is exposed to air in the feed out phase

97
Q

examples of shelf life enhancers

A

➢Propionic acid, sorbic acid and salts and sulphites of these acids
➢Absorbent – pulp and hulls

98
Q

Some commercially available
inoculants

A
  • Sil-All 4x4 – Alltech
  • 4 types of LAB, cellulase, hemicellulase, amylase and pentosanase
  • Silo king – Agriking
  • L. plantarum, pedicoccus spp., anti-oxidants, mould inhibitors, enzymes
  • Agros clamp – Vola
  • L. plantarum, cellulase, hemicellulase
99
Q

what % of sugars in grass

A

2-3%

100
Q

secondary fermentation

A

If the pH decline is not sufficient to inhibit the coliform and clostridia bacteria then pH may rise again

101
Q

what do coliform and clostridia bacteria begin to ferment

A

These bacteria then begin to ferment the lactic acid to produce weaker acids including acetic and butyric acid

102
Q

when should silage tested be carried out and why

A

at around 90 days
- as secondary fermentation wont be detected before 60 days

103
Q

how is secondary fermentations risks increased

A

– Low DM (< 200g/kg fresh)
– Low WSC (< 30g/kg fresh)
– High BC (> 400mEq/kg DM)

104
Q

consequences of secondary fermentation

A
  • decreased levels of DM
  • decreased levels of Digestibility
  • decreased levels of intake
  • decreased levels of protein and energy supply
105
Q

what are the main losses during silage making (3)

A

Main losses are
1. In the field
- 1-2%………extended wilt 6-10%

  1. In the silo
    * Poor fermentation >5%
    * Effluent ≥ 10%
  2. Aerobic deterioration
    * Poor sealing >1%
    * At feed out
106
Q

what are 4 factors affecting losses during silage making

A

Crop
Silage making system
Standard of management
Prevailing weather conditions

107
Q

Factors affecting YIELD of grass silage (7)

A
  • Soil fertility and nutrient availability
  • Pre-closing management
  • Date of harvest
  • Pasture species
  • Pasture age
  • Climatic conditions
  • Losses – utilisable yield
108
Q

factors affecting QUALITY of grass silage (8)

A
  • Soil fertility and nutrient availability
  • Pre-closing management
  • Dead grass
  • Date of harvest
  • Pasture species
  • Pasture age
  • Weeds
  • Climatic conditions
109
Q

what does spring grazing do

A

spring grazing reduced silage yield but increase the total forage yield per ha

110
Q

How does grass growth stage at cutting affect silage quality?

A

slide 65

111
Q

why is silage analysis done

A
  • To access the likely feed value and animal performance
  • To allow ration formulations
  • Identify issues early e.g. Stability or animal health
112
Q

when should you silage sample

A

At least 6 weeks post harvest

113
Q

what are the nutritional qualities when interpreting silage result

A

Nutritional qualities
➢ Dry matter
➢ Dry matter digestability
➢ Metabolisable energy (ME)
➢ Crude protein
➢ NDF and ADF

114
Q

what are the fermentation qualities when interpreting silage result

A

Fermentation qualities
➢ pH
➢ Ammonia nitrogen
➢ VFAs
➢ Lactic acid

115
Q

what is the optimum ph for silage fermentation

A

3.8-4.2

116
Q

what is the optimum ammonia N for silage fermentation

A

Less than 10% (100g/kg)
Preferably round 5%

117
Q

what is the optimum lactic acid for silage fermentation

A

5-30g/kg FW

118
Q

what is the optimum Butyric acid or silage fermentation

A

low as possible

119
Q

what is the optimum VFA’S (Acetic and Butyric acid) for silage fermentation

A

20-40%

120
Q

what are key challenges for the future (4)

A
  • The development of lower cost, reduced labour harvesting systems
  • Increase quality/quantity of feed out product
  • Improved prediction of silage feeding value based on the analysis of the standing crop
  • The development of feeding strategies to improve the efficiency of nutrient capture in silage-based
    systems

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