management involved in making quality silage

1. Management involved in making quality silage
Basim Refat

2. Outline
First part
- Introduction
- Advantages and disadvantages of different silo types
Second part
Importance of excluding air in silos
1. Packing
2. covering

3. Introduction
• Storage losses during ensiling process:
• type of silo
• species, stage of maturity
• moisture content of the ensiled crop
• the efficiency of excluding air and water from the silage.
• This feed loss is made up of the following:
• Surface Spoilage
• Ensiling Losses
• Seepage losses

4. SILO
proper
environment
for ensiling
Exclusion of air from the
ensiling mass
Reducing
feed loss

5. There are several ensilinge methods that will
accomplish the ensiling process
All methods have advantages and disadvantages, and
have widely ranging capital costs.

6. 1. Vertical Silos
(a) open to the atmosphere on top i.e. open- top; or
(b) (b) sealed to control the internal atmosphere - i.e. - oxygen-limiting.
2-Horizontal Silos
• There are two types of horizontal silos –
• Below ground level (i.e., pit or trench)
• Above ground
• Bunker
• Pile or stack or heap or clamp
• Plastic silage bags
• baled silage The main advantage of horizontal silos is their low capital cost
and suitability to feeding livestock in widely separated pens.

7. Vertical silos
built of either concrete or steel
• open to the atmosphere on top i.e.
open- top; or
• sealed to control the internal
atmosphere - i.e. - oxygen-limiting

8. Horizontal silos
1. Below ground level (i.e., pit or trench)
• Trench silos are usually dug into a slope with the "downhill" end open for
drainage and access.

9. 2- Aboveground horizontal silos
• Stack Silage; (Pile) Stack
• Silage Bunker
• Silage Bag
• Baled Silage

10. DM
filling Seepage Gaseous top surface feed out total
---------------------------DM Loss (%) ------------------------------
conventional
tower
80 1-2 7 9 3 1-5 21-26
70 1-2 1 8 4 1-5 15-20
65 1-3 0 8 3 1-5 13-19
60 1-3 0 6 3 1-5 11-17
50 2-4 0 5 3 1-5 11-17
Gas-tight tower
70 0-1 1 7 0 0-3 8-12
60 1-2 0 5 0 0-3 6-11
50 2-3 0 4 0 0-3 6-12
40 2-4 0 4 0 0-3 6-13
Dry matter loss for filling, storage and emptying a variety of silage storages
Based on Forages: The Science of Grassland Agriculture, 4th ed. See Bickert et al (1997).

11. ---------------------------DM Loss (%) -----------------------------
trench or bunker
no cover
80 2-5 6 10 6 3-10 27-37
70 2-5 1 9 9 3-10 24-34
60 3-6 0 10 12 5-15 30-43
trench or bunker
cover
80 2-5 4 9 2 3-10 20-30
70 2-5 1 7 3 3-10 16-23
60 3-6 0 6 4 5-15 18-31
Stack, no cover
80 3-6 7 10 11 3-10 34-44
70 3-6 1 11 19 3-10 37-47
60 4-7 0 12 24 5-15 45-58
Stack, covered
80 3-6 5 8 2 3-10 21-31
70 3-6 0 7 4 3-10 17-27
60 4-7 0 6 6 5-15 21-34
Wrapped Silage
bales
60-70 1-2 0 8 5 1-5 15-20
50-60 2-3 0 6 6 1-5 15-20
DM filling Seepage Gaseous top surface feed out total
Based on Forages: The Science of Grassland Agriculture, 4th ed. See Bickert et al (1997).

12. Effect of storage systems on composition alfalfa
silage
Bunker O2-Limiting Tower p- value
DM, 36.8b 54.0a 49.6a <0.001
CP,% of DM 19.4 20.7 19.7 0.305
NPN, % of Total N 62.3a 55.4b 55.0b 0.014
NH3, % of Total N 13.11a 6.79b 7.14b 0.008
Total AA, % of Total N 32.3 32.2 33.3 0.269
ADF,% of DM 40.5a 34.9b 35.9b <0.001
NDF,% of DM 45.8a 41.5b 41.8b 0.02
Lactate 3.67ab 2.86b 4.42a 0.028
Acetate 2.87a 1.16b 1.46b <0.001
pH 4.84 4.87 4.69 0.34
Luchini et al., 1997

13. Advantage and disadvantages

14. • Silo tower
• Have a smaller surface area exposed to the elements and therefore less
spoilage than horizontal silos
• Horizontal tower
• Horizontal silos generally cost less per stored ton than upright silos
• more adaptable to mobile mixing and feeding systems than vertical silos.
• They can be filled and emptied with conventional farm equipment and
require less energy to move the forage
• Tend to have the greatest losses of dry matter

15. • Drive-over piles
• require low capital investment relative to bunkers
• piles may be constructed with conventional farm equipment, and
fast unloading rates.
• Plastic bags
• low capital investment
• flexible storage system (qualities and types)
• low DM loss if properly managed,
• small feed out face to manage
• Easy to feed out

16. • The stack system
• greatest loss of dry matter during storage, (30-35% ) of the total forage
harvested.
• large amount of surface area exposed to the air
• the stack cannot be packed as densely to exclude oxygen.
• not recommended for long-term storage.
• Bales
• Susceptible to aerobic deterioration owing to their relatively high ratio of
(surface area: volume)
• Chop length typically is longer and density lower for baled crops than for
forage-harvested crops
(Wilkinson, 2005).

17. Silage Bag
• Plastic bags are not reusable
• DM loss can be high if bags are ripped or torn
• specialized equipment is necessary,
• more land area than bunkers or piles,
• small feed out face may be difficult to manage on large dairies feeding high
volumes of silage

18. Importance of excluding air in silos
• Packing
• Covering

19. Packing

20. Packing
Density
DM concentration
permeabilityAerobic
Deterioration
during
Storage

21. 1- Density
• Density and dry matter content determine the porosity of the
silage
• Porosity, in turn, sets the rate at which air moves into the silo
• subsequently the amount of spoilage which occurs during storage and
feed-out.
• The higher the density, the greater the capacity of the silo.
• thus, Higher densities generally reduce the annual cost of storage
per ton of crop by both increasing the amount of crop entering the
silo and reducing losses during storage.
• Tractor weight and packing time are the most important
factors affecting density.
Ruppel et al. (1995)

22. Estimated Dry Matter Density (Est.DMD)
• Est. DMD (lbs DM/ft3 ) = (8.5 + PF × 0.0155) × (0.818 + 0.0136 × D)
• (D) average depth
• (PF) packing factor are calculated as:
• D = average silage depth (ft) = (height at wall + height at center) / 2.
• PF = (W ÷ 𝐿)√𝑁 × 𝐷𝑀 ÷ 𝐶
• W = Proportioned average tractor weight (lbs) for all tractors packing silage.
• L = Layer thickness (inches) of the spread but unpacked crop in the silo prior to driving over it
during the first packing pass.
• N = Number of tractor-packing equivalents, w
• DM = Dry matter content (decimal).
Holmes, 1999

23. Effect of density on silage aerobic stability:
The relationship was influenced by DM
concentration
• DM loss decreased with increasing DM
concentration at higher DM densities (more
than 240 kg DM m−3)
• Lower DM densities (<210 kg DM m−3), DM
loss increased markedly at higher silage DM
concentrations (350–390 kg DM kg FW−1).
(Griswold et al., 2009)

24. • Silage density varied within the silo in which is low top thirds and high
in middle and bottom thirds.
• Density is typically lower at the edges of walled bunkers and unwalled
clamps
• The DM density in 113 silos filled with whole-crop maize was on
average 8% lower close to the outer walls than in the centre of the
silage mass
(Craig et al., 2009)
Effect of density on silage aerobic stability

25. •Fill quickly (no more than 3 days)
•Pack tightly
•Corn silage : (240 kg DM/m3)
•Alfalfa silage: (255 kg DM/m3)
•Grass silage: (210 kg DM/m3)
•6-8 inch (15-20 cm) layers
•Heavy tractors
Holmes and Muck, 2007
Adesogan, 2009
Kung, 2010
Recommendation

26. 2- Silage permeability and porosity
• Porosity is a measure of the voids between the solid particles
• Proportional porosity (ø) can then be calculated as:
ø = 1 − (ρ/ρmax)
• ρ = silage FW density (kg m−3)
• ρmax = maximum silage FW density when all voids are removed.
• (ρmax, kg m−3) = ρmax = [3/(3 − DM)]×1000.

27. Silage porosity is influenced
•FW density,
•the DM content of the crop
•by rate of harvest
(Wilkinson and Davies 2012)

28. Silage permeability and porosity; Density &DM
• Porosity ranges from
0.1 for silage of
• 300 g DM kg−1 FW
• 1000 kg m−3 FW density
0.7 for silage of
• 700 g DM kg−1 FW
• 400 kg m−3 FW density
(Holmes and Bolsen, 2009)

29. Silage permeability and porosity; Harvest rate
Harvest
rate
DM
content
porosity
Holmes and Muck (2007)

30. Covering

31. Losses of DM in pit silages stored either unsealed or sealed

32. Film cover
• The quantity of film applied to bales, usually expressed as number of
layers, and has marked effect on the loss of silage production and
subsequently the subject of evaluation.
• For example using 8 layers instead 6 reduced the mold production
significantly
• So by increasing the number of layer the production of mold would
decrease.
(Jacobosson, 2002).

33. Effect of bale density and number of layers of plastic film on the quality
of baled silage
Adapted from O’Kiley et al (2000)

34. The effect of film colour on silage compostion and mould
growth
Forristal et al. 1999
White plastic is preferable, due to its superior UV
resistance, reduced silage temperatures beneath it, and
reduced freezing problems during winter.
Countries with high sunshine level generally use white
or light-colored film which reduce film temperature and
heat transfer.

35. Covering silage
• Polyethylene cover
• weighted with truck tires,
• the protection provided is highly variable and often changes during storage
• Oxygen barrier film (OB film)
• Alternative to polyethylene seal
• 45µm in thickness,
• Increase the preservation efficiency and nutritional quality of silage within 0.5
to 1.0 m of the surface in bunker silos and drive-over piles.

36. Correlation between the permeability of a film to oxygen and
silage quality
• DM losses due to LD-PE film permeability in relation to film thickness
• losses from 24.4 to 3.2 g kg−1 DM per 30 day period of conservation for film
thicknesses that increased from 25 to 200 µm.
• Oxygen barrier polymers + LD-PE, allow oxygen impermeability to be
increased to values that can only be achieved by LD-PE films that are
thicker than 2000 µm.
Borreani et al. (2013)

37. Oxygen barrier film (OB film) VS Conventional film
Orosz et al. (2012)
Temperature changes of maize silages
during exposure to air

38. Oxygen barrier film (OB film) VS Conventional film

39. Economics of sealing corn silage in bunker silos with standard (Std) plastic and OB film
Variables Std plastic OB film
Silage value. $/tonne 44 44
Silage density in top 0.9 m. kg/m3 624 624
Silage density below top 0.9 m. kg/m3 768 768
Silo depth. m 3.66 3.66
Silo width. m 12.2 12.2
Silo length. m 45.7 45.7
Silage lost in the original top 0.9 m:
unsealed. % of the crop ensiled 50 50
sealed. % of the crop ensiled 20 10
Cost of covering sheet, ¢/m2 50 140
Silage in the original top 0.9 m. tonnes $313 $313
Value of silage in original top 0.9 m. $ $13778 $13778
Value of silage below original top 0.9 m. $ $52000 $52000
Value of silage lost if unsealed. $ $6889 $6889
Value of silage lost if sealed. $ $2755 $1378
Sealing cost. $ $937 $1387
Net value of silage saved by sealing. $ $3196 $4124 1
Values are from the data by Bolsen et al.
(1993) and Berger and Bolsen (2006).