W9- Lecture 26 &27 - Silage Flashcards
(120 cards)
1
Q
for how long has Silage has been used to conserve feedstuffs
A
more than 3000 years
2
Q
what is the most used method for conserving ruminant feed
A
silage
3
Q
what is the Largest harvested Ag crop in the world
A
silage
4
Q
how much of grassland is used in western europe for silage
A
10 million ha of grassland
- 25% of which is baled
5
Q
what is silage
A
Silage is the material produced by the controlled fermentation of a crop of high moisture content
6
Q
how are forage crops preserved
A
fermentation
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
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
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
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
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
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
13
Q
what happens to concentrates when DMD increases
A
concentrates/cow/day decreases
14
Q
silage DM yield
A
increase yield = reduced costs
15
Q
silage digestibility
A
increase yield = reduce digestibility
16
Q
animal performance
A
reduced digestibility = reduced LWG or yield
17
Q
Planning a grass silage strategy (8)
A
- Reduced concentrate supplementation
- Improved milk solids yield
- Improve cow/ ewe condition at calving/ lambing
- Better herd/ flock fertility
- Replacement heifers at target weight
- Improved daily gain
- Shorter finishing period
- Higher annual grass yield
18
Q
what are the objectives of planning a grass silage strategy (3)
A
- high tonnage/ha
- well preserved palatable feed
- required DMD
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
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
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
22
Q
what is forage preservation based on
A
Forage preservation based on spontaneous lactic acid fermentation under anaerobic conditions
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
24
Q
what happens pH in the ensiling process
A
pH decreases and spoilage organisms are inhibited
25
what are the 4 phases of ensiling process ***********
Phase 1: aerobic phase
Phase 2: fermentation phase
Phase 3: stable phase
Phase 4: feed-out phase
26
Phase 1 : aerobic phase (4)
- 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
27
what happens to O2 in phase 1
O2 present is respired by plant material, facultative aerobes and aerobic m/o’s
28
how long does phase 1 last
only a few hours
29
what are active during phase 1: aerobic phase
Enzymes, proteases and carbohydrases will be active during this period
30
Phase 2: fermentation phase (4)
- 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
31
when does phase 2 : fermentation phase start
Starts when the silage becomes anaerobic
32
how long does phase 2 : fermentation phase last for
Lasts a few days to a few weeks (BC - buffering capacity)
33
what happens in phase 2 : fermentation phase if fermentation successful
If fermentation is successful LAB (lactic acid bacteria) develop
34
what is the pH of silage in phase 2: fermentation process
pH decreases to 3.8 – 5.0 depending on DM
35
Phase 3: stable phase (3)
* Relatively inactive period provided air is excluded
* Bacteria decrease in number
* Some remain inactive or as spores
36
which phase is relatively inactive
phase 3: stable phase
- Relatively inactive period provided air is excluded
37
Phase 4: the Feed-out Phase(3)
- 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
38
when does phase 4: feed out phase begin
Begins as soon as the silage gets exposed to air
39
how many phases is phase 4: feed out phase broken into
2
40
what are the two phases of phase 4 : feed pout phase
- Degradation of preserving organic acids
- Rise in pH and activity of spoilage organisms such as bacilli, moulds and enterobacteria
41
does phase 4: feed out phase occur in all silages
Occurs in almost all silages but is dependent on the number and activity of spoilage m/o’s
42
Ensiling: Primary Fermentation
reduction in pH:
– DM
– Fermentable substrate (WSC)
– Buffering capacity (BC)
– Microorganisms present on the crop at ensiling
43
when is WSC increased
WSC is increased when the crop is harvested at a high DM content
44
what do undesirable bacteria prefer
wetter crops
45
how can increase DM can be achieved by
- delaying harvest
– wilting
46
what is optimum DM
25-30% DM
47
how do crops lose water
through the stomata
48
what happens to the stomata after mowing
After mowing stomata close and the cuticle limits the rate of water loss from the plant
49
what helps to accelerate the loss of water
disruption of the cuticle
50
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
conditioning
51
what are the primary fermentable substrate in temperate grasses
– Glucose
– Fructose
– Sucrose
– Fructans
52
Values are a product of water and WSC contents in the grass
(g/L aqueous extract)
53
what is the difference between AM vs PM cutting
PM cutting is the preferred option
54
when do WSC increase
increase WSC with afternoon cutting
55
PM cutting
* 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
what effect do increasing LIGHT INTENSITY have on DM and WSC
Increasing light intensity increases DM and WSC
57
What effect does increasing TEMP have on DM and WSC
Increasing temperature increases DM and reduces WSC
58
what effect does increase Water supply have on DM & WSC
Increasing water supply reduces DM and WSC
59
What is buffering capacity (BC)
The equivalents of acid per unit DM required to lower crop pH from 6 to 4
60
What is the typical BC in grass range from
250 to 350 mEq/kg DM
61
how is BC measured
mEq/kg DM
62
when is BC higher /lower
BC is
- higher in legumes
- lower in maize than grass
63
Microorganisms - Epiphytic m/o’s
* Pseudomonads
* Enterobacteria
* Actinomycetes
* Filamentous fungi
* Yeasts
* Clostridia spores
* Acetic acid bacteria
* Homofermentative lactic acid bacteria
* Heterofermentative lactic acid bacteria
* Propionic acid bacteria
64
what is homofermentative bacteria
Homofermentative – ferment 1 mole of glucose or fructose to 2 moles of lactic acid
65
what is heterofermentative bacteria
Heterofermentative – produce lactic acid plus acetic acid, ethanol or mannitol
66
what are most lactic acid bacteria associated with silage
Most LAB associated with silage are capable of fermenting sucrose, hexose's and pentoses
67
what does clostridia inhibit
Clostridia – inhibited growth in the presence of oxygen, acidic pH, low temp or low water activity
68
what does wet silage result in
poor fermentation
69
what does Saccharolytic clostridia ferment
sugars and LA to produce butyric acid
70
what does Proteolytic clostridia ferment (undesirable microorganism)
amino acids producing amines and ammonia (undesirable microorganism)
71
what does enterobacteria spp ferment
Ferment carbohydrates to short chain organic acids – acetic acid, ethanol, hydrogen
72
what sort of activity has Enterobacteria spp
weak proteolytic activity
73
what does Enterobacteria spp produce
produce ammonia and nitrous oxide
74
what does Enterobacteria spp increase but also decrease
May increase early in ensilage but decrease rapidly with declining pH
75
Fermentation equations
Enterobacteria or coliform
- Glucose + 3ADP + P Acetate + Ethanol +2CO2 + 2H2 + 3ATP + 2H2O
76
fermentation equation - yeast
Yeasts
Glucose + 2ADP + 2P 2 Ethanol +2CO2 + 2ATP
77
fermentation equation - Homofermentative LAB
Glucose or Fructose + 2ADP + 2P 2 Lactate + 2ATP + 2H2O
78
Fermentation equations- Heterofermentative LAB
Glucose + ADP + P Lactate + Ethanol +CO2 + ATP + H2O
3 Fructose + 2ATP + 2P Lactate + Acetate + Mannitol + CO2 + 2ATP + H2O
79
fermentation equation: clostridia
2 Lactate + ADP + P Butyrate + 2CO2 + 2 H2 + ATP + 2H2O
80
definition of additives
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
what is the aim to achieve when related to additives
Aim to achieve a low and stable pH as quickly as possible with LA the primary fermentation product
82
what can additives improve
the fermentation quality of silage
83
additive types (7)
* Acid based additives
* Sugar based additives
* Enzymes
* Enzyme/salt mixtures
* Salt mixtures
* Inoculants
* Absorbent
84
3 classes of additive
1. Fermentation promoters/stimulants
2. Fermentation inhibitors
3. ‘Shelf-life’ enhancers
85
what does Fermentation
promoters/stimulants provide
Provide/produce extra fermentable substrate to/from the crop
- must have sufficient WSC
86
examples of Fermentation
promoters/stimulants
Examples:
➢Sugar based compounds e.g. molasses
➢Enzymes
➢Inoculants
87
2 main enzymes
Cellulases and hemicellulases
88
why are enzymes used instead of sugars
Used instead of sugars to generate extra substrate by breaking down cellulose and hemi-cellulose
89
what are enzymes used with
Used with crops of low ensilability esp. low WSC
90
what are inoculants based on
Based on Lactobacillus plantarum
91
when are inoculants effective
Only effective when there is adequate WSC
92
what should inoculants outnumber
Inoculants should outnumber the native bacteria 10:1 (add 106 CFU/g)
93
what do inoculants produce
a more rapid pH decline
94
what do fermentation inhibitors do
Restrict the fermentation and prevent the development of undesirable bacteria
* Reduces pH as the crop enters the silo
95
examples of fermentation inhibitors
Examples:
➢Acids
- formic acid and sulphuric acid
➢Acid salts
- calcium formate and sodium nitrate
96
what do shelf life enhancers reduce
Reduces the aerobic spoilage and therefore increase shelf life once it is exposed to air in the feed out phase
97
examples of shelf life enhancers
➢Propionic acid, sorbic acid and salts and sulphites of these acids
➢Absorbent – pulp and hulls
98
Some commercially available
inoculants
* 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
what % of sugars in grass
2-3%
100
secondary fermentation
If the pH decline is not sufficient to inhibit the coliform and clostridia bacteria then pH may rise again
101
what do coliform and clostridia bacteria begin to ferment
These bacteria then begin to ferment the lactic acid to produce weaker acids including acetic and butyric acid
102
when should silage tested be carried out and why
at around 90 days
- as secondary fermentation wont be detected before 60 days
103
how is secondary fermentations risks increased
– Low DM (< 200g/kg fresh)
– Low WSC (< 30g/kg fresh)
– High BC (> 400mEq/kg DM)
104
consequences of secondary fermentation
- decreased levels of DM
- decreased levels of Digestibility
- decreased levels of intake
- decreased levels of protein and energy supply
105
what are the main losses during silage making (3)
Main losses are
1. In the field
- 1-2%.........extended wilt 6-10%
2. In the silo
* Poor fermentation >5%
* Effluent ≥ 10%
3. Aerobic deterioration
* Poor sealing >1%
* At feed out
106
what are 4 factors affecting losses during silage making
Crop
Silage making system
Standard of management
Prevailing weather conditions
107
Factors affecting YIELD of grass silage (7)
* Soil fertility and nutrient availability
* Pre-closing management
* Date of harvest
* Pasture species
* Pasture age
* Climatic conditions
* Losses – utilisable yield
108
factors affecting QUALITY of grass silage (8)
* Soil fertility and nutrient availability
* Pre-closing management
* Dead grass
* Date of harvest
* Pasture species
* Pasture age
* Weeds
* Climatic conditions
109
what does spring grazing do
spring grazing reduced silage yield but increase the total forage yield per ha
110
How does grass growth stage at cutting affect silage quality?
slide 65
111
why is silage analysis done
- To access the likely feed value and animal performance
- To allow ration formulations
- Identify issues early e.g. Stability or animal health
112
when should you silage sample
At least 6 weeks post harvest
113
what are the nutritional qualities when interpreting silage result
Nutritional qualities
➢ Dry matter
➢ Dry matter digestability
➢ Metabolisable energy (ME)
➢ Crude protein
➢ NDF and ADF
114
what are the fermentation qualities when interpreting silage result
Fermentation qualities
➢ pH
➢ Ammonia nitrogen
➢ VFAs
➢ Lactic acid
115
what is the optimum ph for silage fermentation
3.8-4.2
116
what is the optimum ammonia N for silage fermentation
Less than 10% (100g/kg)
Preferably round 5%
117
what is the optimum lactic acid for silage fermentation
5-30g/kg FW
118
what is the optimum Butyric acid or silage fermentation
low as possible
119
what is the optimum VFA'S (Acetic and Butyric acid) for silage fermentation
20-40%
120
what are key challenges for the future (4)
* 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
