Transcript POULTRY BREEDING

SILAGE MAKING
Assoc. Prof. Dr. István HULLÁR (2010.)
FORAGE PRESERVATION
AIM:
to make forage storable;

inhibition of nutrient loss caused by


action of plant enzymes
microbes.
METHODS OF PRESERVATION
1. Haymaking:
preservation is based
on drying;
2. Silage Making:
preservation is based
on an acidification.
SILAGE MAKING
Why?
Preservation of forage high in moisture
without drying;
How to do that?
Based on an acidification due to lactic acid
fermentation under anaerobic conditions.
TERMS
Silage: forage of high moisture content
conserved by anaerobic fermentation (DM:
30-35%);
Haylage: low-moisture silage (wilted forage) (DM: 40-50%);
Ensilage: silage making (process);
Silo: the place for herbal fermentation.
METHOD OF SILAGE MAKING
1. Harvesting, chopping
2. Filling of the silo
3. Pressing to exclude air (oxygen).
4. Covering to
- achieve and maintain anaerobic conditions,
- exclude aerobic microbes,
- develop lactic acid bacteria.
PRICIPLES OF PRESERVATION
Microbial fermentation of soluble carbohydrates

Production of organic acids
(1.5% Lactic acid, 0.5% Acetic acid, less than 0.1% Butiric acid)

Acids produced reduce the pH up to 4.2 (corn silage)

Acidity inhibits further fermentation

Silage is ready.
PHASES OF FERMENTATION
1st phase
- plant respiratory enzyme activity as long as
conditions are aerobic,
- production of CO2 decreases the pH,
- destruction of plant tissues,
- loss of cell integrity and turgor.
PHASES OF FERMENTATION
2nd phase (phase of fermentation: 10-20 days)
- aerob micro organisms are replaced by anaerobs,
- number of lactic acid bacteria is increasing,
- mobilization of soluble carbohydrates,
- production of lactic acid,
- decrement of the pH;
3rd phase (phase of standstill)
- pH is standard,
- no more microbial activity.
Some fermentation pathways in ensilage
Lactic acid bacteria 
production of lactic acid
1. Homofermentative
1 mol glucose  2 mol lactic acid
(Lactobacillus plantarum, L. casei, Pediococcus cerevisiae, etc.)
2. Heterofermentative
1 mol glucose  1 mol lactic acid + ethanol + CO2
(L. brevis, L. buchneri, etc.).
Some fermentation pathways in ensilage
Coli-Aerogenes-Group (optimum pH: 7.0)
- fakultative anaerobes,
- fermentation of carbohydrates  acetic acid +
CO2

- less palatable,
- waste of carbohydrates.
Some fermentation pathways in ensilage
Clostridia (pH opt. 7.0-7.5)  Butiric acid;
Substrates:
- Carbohydrates  Butiric acid  waste of
carbohydrates,
- Lactic acid  Butiric acid  worse dissociation (higher
pH);
- Amino acids  NH3 (buffer)  higher pH + toxic
amines (Lys → Cadaverine; Arg → Putresscine; Tyr → Tyramine).
Some fermentation pathways in ensilage
Yeasts (pH opt. 5.0);
Substrates:
- Lactic acid,
- sugars;
Products:
alcohol + CO2 + H2O.
Some fermentation pathways in ensilage
Moulds
Substrates:
- carbohydrates,
- proteins;
Consequences:
- waste of nutrients,
- lower feed intake.
Factors influencing the fermentation
1. DM content of green forages
- Corn silage: 30-35%
- Haylage: 40-50% (wilted forage)
2. Amount of easily fermentable carbohydrates
- corn silage: 290 g/kg (easily fermentable),
- grass silage: 120 g/kg (moderately fermentable),
- alfalfa silage: 65 g/kg (difficultly fermentable);
3. Crude fibre → elastic (pressing is difficult);
4. Temperature (27-38oC).
Factors influencing the fermentation
5. Buffering capacity (Bc)
Amount of Lactic acid (g) required to reduce pH
of 1 kg DM to 4.0;
- BcCorn silage: 40 g/kg DM;
- BcAlfalfa: 90 g/kg DM;
Factors increasing the Buffering capacity
a) high level of CP  NH3,
b) alkali metals (Ca, Mg).
Losses in Silage Making
a) Oxidation losses
Action of plant and microbial enzymes on
substrates;
b) Fermentation losses: harmful microbes;
c) Effluent losses (seepage):
- initial moisture content of the crop;
- rain (uncovered silo).
TYPES of SILOS
1. Horizontal Silos.
2. Tower (upright) Silos.
3. Plastic Bag Silos.
SILAGE ADDITIVES
1. FERMENTABLE CARBOHYDRATES
Molasses,
Dried sugar beet pulp,
Cereal grains.
SILAGE ADDITIVES
2. PRESERVATIVES
Mineral acids (hydrochloric, sulfuric, and
phosphoric acids or the mixture of them),
 setting up the required pH;
Organic acids: formic acid, propionic acid,
Disadvantages of their use:
- can disturb the mineral metabolism of the host,
- danger in their use (corrosive, difficult to
handle).
SILAGE ADDITIVES
3. BIOLOGICAL ADDITIVES
Bacteria cultures (lactic acid producers)
(e.g. Lactobacillus acidophilus,
Streptococcus faecium).
EVALUATION OF SILAGE QUALITY
1. Subjective methods (visual appearance)
(colour, smell, taste, texture)
- colour: green vs. brown (darker colour indicates
heat damage),
- smell: aromatic (butyric acid is stinking),
- taste: sweet vs. acidic (acetic acid causes acidic
taste, reduces the feed intake),
- texture: firm, preservation of particle’s
structure.
EVALUATION OF SILAGE QUALITY
2. Objective methods
- chemical compositions (DM, CP, EE, CF,
NFE, NDF, ADF, ADL),
- acidity (pH),
- organic acid composition (1.5% lactic
acid, 0.5% acetic acid, less than 0.1%
butyric acid).
NUTRITIVE VALUE OF CORN SILAGE
DM (%)
CP (%, on DM basis)
NEl (MJ/kg, on DM basis)
CF (%, on DM basis)
Corn silage
30-35
10
6-7
20.
Quantities of Silage Fed to Animal Species
Cattle
Sheep
Horse
Sow
Corn silage
kg/animal/day
25-30
5
10-15
5-6.