SILAGE MAKINGSILAGE MAKING Assoc. Prof. Dr. István HULLÁR (2010.)Assoc. Prof. Dr. István HULLÁR (2010.)

FORAGE PRESERVATIONFORAGE PRESERVATION

AIM:

to make forage storable;

inhibition of nutrient loss caused by

action of plant enzymes microbes.

METHODS OF PRESERVATIONMETHODS OF PRESERVATION

1. Haymaking:preservation is based on drying;

2. Silage Making:preservation is based on an acidification.

SILAGE MAKINGSILAGE 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.

TERMSTERMS

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 MAKINGMETHOD 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 PRESERVATIONPRICIPLES 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 FERMENTATIONPHASES 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 FERMENTATIONPHASES 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 ensilageSome fermentation pathways in ensilage

Lactic acid bacteria production of lactic acid1. Homofermentative1 mol glucose 2 mol lactic acid

(Lactobacillus plantarum, L. casei, Pediococcus cerevisiae, etc.)

2. Heterofermentative1 mol glucose 1 mol lactic acid + ethanol + CO2

(L. brevis, L. buchneri, etc.).

Some fermentation pathways in ensilageSome 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 ensilageSome 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 ensilageSome fermentation pathways in ensilage

Yeasts (pH opt. 5.0);

Substrates:

- Lactic acid,

- sugars;

Products:

alcohol + CO2 + H2O.

Some fermentation pathways in ensilageSome fermentation pathways in ensilage

Moulds

Substrates:

- carbohydrates,

- proteins;

Consequences:

- waste of nutrients,

- lower feed intake.

Factors influencing the fermentationFactors 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 fermentationFactors 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 MakingLosses 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 SILOSTYPES of SILOS

1. Horizontal Silos.

2. Tower (upright) Silos.

3. Plastic Bag Silos.

SILAGE ADDITIVESSILAGE ADDITIVES

1. FERMENTABLE CARBOHYDRATES

Molasses,

Dried sugar beet pulp,

Cereal grains.

SILAGE ADDITIVESSILAGE 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 ADDITIVESSILAGE ADDITIVES

3. BIOLOGICAL ADDITIVES

Bacteria cultures (lactic acid producers)

(e.g. Lactobacillus acidophilus, Streptococcus faecium).

EVALUATION OF SILAGE QUALITYEVALUATION 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 QUALITYEVALUATION 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 SILAGENUTRITIVE VALUE OF CORN SILAGE

Corn silage

DM (%) 30-35

CP (%, on DM basis) 10

NEl (MJ/kg, on DM basis) 6-7

CF (%, on DM basis) 20.

Quantities of Silage Fed to Animal SpeciesQuantities of Silage Fed to Animal Species

Corn silage

kg/animal/day

Cattle 25-30

Sheep 5

Horse 10-15

Sow 5-6.