Silage

Conservation of fodder

Silage making

Vishnu Vardhan Reddy.PTVM/2015-029

What is Conservation of fodder

• Conservation of fodder means preservation and careful

maintenance of certain quantities fodder unchanged

during chemical reactions or physical transformations

of fodder when it is excessively available for future

needs.

What for Conservation of fodder

• To preserve feed when it is available in excess.

• To maintain optimum nutritional value of fodder.

• To shift available feed from the present to the future.

• To move feed from one location to another location.

• To assist pasture management.

Methods of Conservation

• Hay and silage are the main methods of conserving

forage

• Hay is preserved by drying and will generally keep while

it is kept dry.

• Silage involves natural fermentation, which produces

lactic and other acids, which ‘pickle’ or preserve the

forage.

What is silage

Silage is the green material produced by controlled

fermentation of the green fodder crop retaining the

high moisture content.• Contain 20-40% DM and 14-16% CP

Advantages of silage making

• Silage can be prepared from green fodder when

the weather does not permit for haymaking.

• Silage can be prepared from plants having thick

stems and are generally not very suitable for

haymaking like sorghum, maize

Advantages cont.…• Weeds can also be utilized along with main fodder

crops for silage making. Silage making kills majority of

weed seeds.

• It is highly palatable.

The organic acids produced in the silage are similar

to those normally produced in the digestive tract of the

ruminants and therefore are used in the same manner.

Principle of Silage making• Anaerobic condition is first and foremost requirement

for silage making, as it allows lactic acid bacteria to

grow, which converts sugars into lactic acid, a strong

organic acid.

• As pH declines, the degrading actions of plant enzymes

and undesirable bacteria are inhibited and at pH 3-4,

most degrading enzymes are inhibited and the growth

of lactic acid bacteria is also inhibited.

Principle cont.….

Sugars+Oxygen Carbon dioxide+Water+Heat

this reaction is prevented and nutrient loss is reduced.

• And in simple words the principle of silage is the same

as that in making pickles.

Selection of crops for silage making

It is easier to ensile forages that have:

• High level of fermentable sugar.

• Low level of protein.

• Low buffering capacity.

• Should have about 35 per cent dry matter at the

time of ensiling.

Selection of crops cont.…• Pasture grasses: Elephantgrass (Napiergrass), Guineagrass,

Rhodesgrass, Sudangrass, Setaria, Ruzigrass, etc.

• Pasture legumes: Stylo.

• Fodder tree: Leucaena, etc.

• Straws: rice straw, wheat straw, soybean chaff, peanut

hulls, etc.

• Corn, Sorghum.

• Farm by-products.

Site for construction of silo

• The place where we intended to construct silo should be

elevated from other places.

• The place must be free from water clogging.

• Walls of silo pit must be leak proof.

• It should at least six feet away from form animal shed.

• If it is possible construct the silo south side of the animal

shed.

Size of a silo

• The silo size is determined by a herd size, the amount of daily feed, the number of feeding days and packed density of the raw materials.

Making of Silage

Harvesting of fodder.

• Pasture grasses: From early heading to heading stage.

• Pasture legumes: From budding to early flowering stage.

• Corn: Yellow ripening stage.

• Sorghum: Dough stage.

Making of Silage cont.… Moisture Testing 65-70 % moisture level in green

fodder is ideal for silage making (if moisture level is

high Wilting is required).

High moisture content leads to poor fermentation.

Chopping of forage to short length (1-3 cm).

so that the packing density is kept higher, lactic acid

fermentation takes place in good condition.

Making of Silage cont.…

Spreading chopped fodder to make a bed of 2 feet

height in Silo-Pit.

Compact forage as tightly as possible with help of

tractor or hand roller or any heavy object.

Sprinkle Molasses solution over it at 2-3% of the

material weight.

If the moisture content of the raw material is high,

molasses addition may have no effect.

Making of Silage cont.… Addition of bran and other silage additives.

When the moisture content of the raw materials is 80% or

higher, brans are evenly sprayed at about 10% of material

weight.

Sprinkle Silage SAVOR solution uniformly over the fodder bed.

Repeat steps no. 4-7 at least 6 to 10 times till the Silo-Pit is

completely filled up.

Making of Silage cont.…

Seal the pit airtight with plastic cover.

Plastic covers should be pressed with heavy objects like

bricks or tire.

Maintain sealing for 45 days.

Once silo-pit will be open, it should be finished within 45-

60 days to avoid fungal contamination.

Silage additives

Silage additives should

1.increase DM (nutrient) recovery,

2.improve animal performance

3.decrease heating and molding during storage and feed

out.Direct acidifiers• inorganic/organic acids –decreases pH • E.g. Sulphuric and formic acids.

Silage additives cont.…Fermentation inhibitors

• Immediately decreases pH

• Sterilents to inhibit micro flora

• e.g. formaldehyde, Maxgrass, Add safe, sorbic acid salts

Fermentation stimulants

• provide substrates for fermentation e.g. molasses

• enzymes -speed-up fermentation e.g.. cellulase

Silage additives cont.…

Inoculants -microbial cultures

• E.g. homofermentative lactobacille.

Others

• Specific antibiotics/ to nutritive value (NaCl, starch,

CaCO3etc)

Silage inoculants

• The primary purpose for adding bacterial inoculants

is to increase the number of lactic acid-producing

bacteria. Most commercial inoculants for silage

include

• Homo- fermentative lactic acid bacteria

e.g. Lactobacillus plantarum, Enterococcus

faecium and Pediococcus spp.

• Hetero-fermentative LAB is include, L. buchneri

Effect of inoculants on silageIntake (kg day-1) Uninoculated Inoculated

Dry matter 8.82b 8.82a

Crude protein 1.10b 11.04a

Neutral detergent fiber 5.63b 1.40a

Non fiber carbohydrate 2.56b 5.18a

Ether extract 0.55b 0.65a

Ash 0.26b 0.33a

Digestibility (%)Dry matter 75.03b 79.91a

Crude protein 72.30b 76.35a

Neutral detergent fiber 62.50b 70.56a

Non fiber carbohydrate 85.66b 89.68a

Ether extract 66.71b 83.26a

Ash 48.08b 65.37a

Fermentation of Silage

Types of fermentation in Silage formation

Homolactic fermentation (homofermentative pathway)

• Very desirable, common in high sugar grasses,

• sugars fermented to lactic acid, low pH nutrient loss

• mediated by Lactobacillus plantarum, L acidilacti etc.

Heterolactic fermentations (heterofermentative pathway)

• Less desirable, occurs when limited sugars are available,

• Mediated by Lactobacillus brevis, L. buchneri.

• Sugars mainly fermented to acetic acid, & alcohols.

• Less efficient than Homolactic fermentation.

Secondary fermentation

• Very undesirable.

• Degradation of lactate by clostridial bacteria to Ac & Bu

• Facilitated by high moisture contents & high pH

Fermentation pathwaysFermentation Substrate

(Microbe) Product Nutrient Losses

Homolactic fermentation

Glucose (L. plantarum)

2 x Lactic acid(Low pH) Low

Heterolacticfermentation

Glucose (L. buchneri)

1 x Lactic & acetic acids,

ethanol & CO2 (Moderate pH)

Moderate

Secondary fermentation

Lactic acid(Clostridia)

Butyric acid + CO2(High pH) High

Aerobic spoilage Glucose, lactic acid (Yeasts & molds) Ethanol, CO2 Very high

Fermentation process of silage

The first stage (Respiratory stage)

• The packed raw materials are still respiring

immediately after chopped and consumes oxygen.

• The temperature will rise to about 32ºC around 4 days

after packing.

The second stage (Early fermentation)

• Production of acetic acid, formic acid and other organic

acids as a result of the growth of facultative aerobic

bacteria such as Enterobacteria.

• The silage pH slowly changes from about 6.0 to 4.0

The third stage (Lactic acid fermentation)

• Lactic acid fermentation begins by lactic acid bacteria

witch are strictly anaerobic about 3 days after packing

chopped materials. and acetic acid production declines.

The fourth stage (Cont.… of Lactic acid fermentation)

• Lactic acid production continues for about 2 weeks.

• The temperature goes down slowly to about the normal

atmospheric temperature. and pH is maintained at 4.0

The fifth stage (Stabilization phase)

• Due to the presence of lactic acid, further degradation is

inhibited, as bacterial and fungal growths are checked.

• The lactic acid fermentation completes in about 20 days,

and the silage product is finished.

Fermentation at glance

If the lactic acid production is insufficient, butyric acid

fermentation begins and quality deterioration occurs.

Phases of silage conservation

Pre-

ensi

ling • Aerobic

• Plant respiration

• Protease activity

• Epiphytic organisms

• pH 5.5-6.5

Ensi

ling • Anaerobic

• Sugar fermentation

• LAB dominance

• Lactate & VFA formation

• pH 3.8 -5 Feed out

Feed

out

• Aerobic• Fungal

resurgence• Acetic

bacteria, yeasts, molds

• pH 6 –9• <47% DM

loss

Chemical changes during fermentation

• Sugars are fermented into volatile fatty acids (VFA) like

lactic, acetic, propionic & butyric)acids by anaerobic

microorganisms.

• The formation of the acids reduces the pH (target = 4)

• Protein is degraded into ammonia and NPN (target

=<100g ammonia/kg total Nitrogen)

Chemical changes during fermentation

Day 1-10 Day 11-20 Day 21-30 Day 31-40 Day 41-50

SugarsCPAmmoniaButeric acidAcetic acidLactate

Grass Silage

Grass & silage protein fractions

Grasses Silage0%

20%

40%

60%

80%

100%

120%

AmmoniaNitrateAminesPeptidesNuclic acidsFree amino acidsTrue Protien

Kinds of silos1) Stack silo

• Simplest type of silo.

• A plastic sheet of 0.1 mm thickness is spread over the ground, and

similarly chopped silage materials on the sheet are entirely covered

with a plastic sheet. Proper tread pressure and complete sealing are

required.

2) Bunker silo

• A bunker silo is generally built on the ground but there

are other building methods to build a silo using the

configuration of the ground (slope 3-5%) or a semi

underground type, which is half below from the

ground level.

• Side walls made of wood and concrete are needed, and

the interior is preferably sealed by plastic sheets.

Proper tread pressure has to be applied, and complete

sealing is required.

• Supports are needed so that the side walls do not fall

outside.

• The width of the front should be such that the total

amount of silage per day can be taken out with a

thickness of 20-30 cm to prevent aerobic deterioration.

3) Pit/Trench silo

• A trench silo can be built by simply digging the ground,

but it is better to place plastic sheets inside to prevent

loss.

• A trench silo whose interior is coated with concrete can

be used for a long time

4) Plastic bag silo

• In this type plastic bags with thickness of 0.1 mm are

taken and fill bags with chopped raw materials,

compressed as much as possible to remove the

internal air and then sealed completely.

5) Fenced silo (framed silo)

• The frame is made of bamboo, wooden, iron materials,

etc., the shape of cross section may be circular or

rectangular. and inside is sealed with plastic sheets.

6) Tower silo

• In this type storage silos are

cylindrical structures, typically

10 to 90 ft. (3 to 27 m) in

diameter and 30 to 275 ft. (10

to 90 m) in height .

• Tower silos containing silage

are usually unloaded from the

top of the pile.

Judging the quality of silage

The quality of silage can be judged by its color, smell,

taste and touch.

• Color: In general, pale yellow indicates good quality. If

the color is from dark brown to dark green, the silage

underwent bad fermentation and is of bad quality.

• Smell: Acidic or a sweet-sour pleasant smell indicates

good quality. On the other hand, if there is a manure

smell or putrid smell and it is so repugnant that one

cannot put the silage near one's nose, the quality is

poor.

• Taste: If the silage tastes sour and there is no problem

in putting it in one's mouth, the quality is good. On the

other hand, if the silage tastes bitter and one cannot

put it in one's mouth, the quality is poor.

• Touch: When squeezing the silage tightly in a hand and

then opening the hand, if the silage breaks slowly into

two, that silage is of good quality. If the silage breaks

into small pieces separately, the silage is deficient in

moisture content. If water is dripping, the moisture

content of the silage is too high.

Feeding of silage

2 - 3 year old cattle 11-13 kg

3 - 8 year old cattle 13-22 kg

sheep 1-1.5 kg per 45 kg. live wt.

goats 1-1.5 kg per 45 kg. live wt.

Nutrient losses in silage

Energy losses in silage and causative factorsProcess Classification Approximate

loss (%) Causative factors

Residual respiration Unavoidable 1-2 Plant enzymes

Fermentation Unavoidable 2- 4 Microorganisms

Effluent Mutually 5 -7 Dry matter content is too low

Wilting losses unavoidable 2- 5 Weather, technique, crop

Secondary fermentation Avoidable 0 - 5 Buffering capacity, Dry

matter content is too low

Aerobic deterioration

during storageAvoidable 0 -10

Delayed filling and compaction, sealing, crop

susceptibility

Aerobic deterioration after

unloading Avoidable 0 -15

As above, DM content, season, unloading technique and rate

Total 7- 40

Factors enhance the nutrient quality of silage

Add dry matter to reduce moisture content:

To reduce seepage losses and

To provide a more suitable medium for the

fermentation process.

• Generally, grasses and legumes are wilted or dried to

an average of about 65% moisture or less depending

on the type of storage used.

• If in any case, forage crops are harvested at too wet

for silage, the following guideline for dry matter

addition may be used.

Coarsely ground cereal grains or chopped grasses are

used @ for 5% reduction moisture about 150 to 200

pounds of material is added per ton of wet forage

weight.

Add water to increase moisture content:

• If forage crops to be stored as silage are too dry,

then packing to exclude air is difficult.

• Under such conditions, water must be added to raise

the moisture content to the desired level to increase

forage moisture content 1% unit approximately 5 to 6

gallons/ ton of ensiled material.

Rate, amount and kind of acid production:

• The rate, amount and kind of acid produced is

influenced by the moisture content of the chopped

forage and the readily available carbohydrate content

of the forage.

• Acid production is essential in the keeping qualities of

silage.

Adding of molasses

• Molasses is an excellent carbohydrate or sugar source

for legumes and grasses containing 75 to 80%

moisture.

• For legumes, about 80 pounds of molasses per ton is

required, and for grasses 40 pounds is generally used.

Acidifying the silage:

• Acidifying silage, using a strong acid, generally

practiced in Europe on high-moisture grass silage.

• The purpose was to produce an immediate acid

condition rather than waiting for the silage to produce

its own acid.

• This practice is not recommended in the USA because

of its high cost, the corrosive nature of the acids and

low forage palatability.

Inhibition of bacteria and mold growth:

• Generally formic and propionic acids are commonly used

as preservative to prevent bacterial and mold growth.

• The major benefit of adding these acids to silage is

reduce the spoilage in open storage structures.

• Formic acid is added to hay crop silages @ 0.45% of the

wet weight or 2.25% of the DM weight.

• Propionic acid is added @ 0.5 to 1.0% of the wet forage

weight.

Increasing the nutrient content of silage

• To increase the nutritive value of silages, Materials

such as cereal grains, molasses, dry forages, limestone,

urea and anhydrous ammonia etc., are added to silage.

• Commercial products are also available that contain

one or more of the above materials.

• Limestone (calcium carbonate) is sometimes added to

corn silage to increase the calcium content and extend

the fermentation process @ 10 to 20 pounds per ton of

corn silage.

• To increase the protein content of silage, Sometimes

Urea and anhydrous ammonia, NPN sources are also

added.

• Usually they increase the forage protein content about

4% units on a dry matter basis.

NPN Sources Form % Nitrogen Application Rate

(lbs./wet ton)

Urea dry 45 10

Mono-ammonium phosphate dry 11 202

Pre-mixed ammonia-water liquid 20-30 17-25

Anhydrous ammonia gas 81 6-7

Ammonia, cold flow gas-liquid 81 6-7

THANK YOU

Vishnu Vardhan Reddy.PTVM/2015-029