Dr. Limin Kung of the University of Delaware presented this information for DAIReXNET on February 17, 2014. The recorded webinar can be found at http://www.extension.org/pages/15830/archived-dairy-cattle-webinars#.UwPQJc4gvZc.

1. Forage Fermentation:
How to Make Good Silage
Limin Kung, Jr.
Dairy Nutrition & Silage Fermentation Lab

2. Definition of a high quality
silage/forage
Nutrient recovery
 High nutritive
concentration



(CP, starch, etc.)
High digestibility
by rumen microbes

3. Harvest Quality and Silo Management Have
Profound Effects on Silage Quality at Feeding
Poor quality forage from field->
Poor harvest and silo management ->
= Poor quality silage at feeding
Poor quality forage at harvest ->
Excellent harvest and silo management ->
= Poor quality silage at feeding
High quality forage at harvest ->
Poor harvest and silo management ->
= Poor quality silage at feeding
High quality forage at harvest ->
Excellent harvest and silo management ->
= Excellent quality silage at feeding
Kung, 2001

4. Value of Potential Forage Loss
in the Silo –$35/t for Corn Silage
Tons of
Silage/yr
----- DM Losses-----
<10%
15%
20%
1,000
3,500
5,250
7,000
2,000
7,000
10,500
14,000
3,000
10,500
15,750
21,000
Good
Poor Management
Expect losses in milk production and/or greater
concentrate costs when feeding poorer silage
L. Kung, Jr., University of Delaware

5. Challenges with Alfalfa Silage






High buffering capacity -> slow fermentation
Difficult to wilt quickly
Easily goes clostridial when DM is low (<30%)
Substrate for fermentation can be limiting
during cloudy weather, heavy rains, prolonged
wilts
Difficult to pack when dry
Easily heat damaged at higher DM (>50%)
L. Kung, Jr., University of Delaware

6. Help with Alfalfa Silage

Minimize wilting time (wide swath?)

Maximize dry down hours during daylight

Wilt to at least 35% DM

Avoid excessive DM (not more than 50%
DM)

Avoid being rained on

Avoid mowing and harvest under cloudy
conditions
L. Kung, Jr., University of Delaware

7. Consequences of Extreme DM on
Alfalfa and Grass Silages
Too Wet (<30%)
Too Dry (>45-50%)
-Clostridia
-Tough to pack
protein degradation
-Poor stability
DM/energy loss
-Heat damage CP
low digestibility
leading to low
butyric acid/amines
digestibility
-Seepage
L. Kung, Jr., University of Delaware

8. Consequences of Harvesting Corn
for Silage at Extreme DMs
Too Early
Optimum
Too Late
(<28-30% DM)
(>40% DM)
Low [starch]
Low starch digestion
Low [energy]
32-36% DM
Low acid production
Excess [acid]
Tough to pack
High acetic acid
Poor aerobic stability
Seepage
L. Kung, Jr., University of Delaware

9. Optimum Harvest Time for
Corn Silage
~32 to 36% whole plant DM
Good starch content and digestibility
Good fiber digestion
Good packing in the silo
L. Kung, Jr., University of Delaware

10. Effect of Corn Silage Maturity on Starch
Digestion in the Total Tract
adopted from Shaver, 2002
100
100
% Starch 95
Digestion
90
90
Unprocessed
80
80
48
.8
46
45
.6
45
44
43
42
.8
40
.6
39
.4
38
37
.2
35
40
Whole Plant Corn DM%
34
.6
33
.4
32
31
.2
30
36
65
.8
70
70
black layer
.4
½ milk line
.2
75
30
St arch dig. %
85
Dry Mat t er %
*Based on data of Bal et al., 2000; Dhiman et al., 2000; Rojas-Bourrillon et al.1987

11. Set Chop Length at Harvest!!
Item
C. Silage*
Processed**
Top
3-8%
5-15%
Middle
45-65
>50
Lower
20-30
<30
Pan
<5
<5
*Heinrichs, PSU **Hutjens, UI

12. Processing for Corn Silage
Cracks the kernel open
to expose starch -> +
digestion
Reduces TMR sorting
Improves silage
packing
L. Kung, Jr., University of Delaware

13. Fecal Starch and Digestibility
Goal is to have less than 3-4% fecal starch
1%-unit decrease in fecal starch ~ 1 pound more milk
Range in starch: 2.3 – 22.4%
(Ferguson, 2006)

14. Corn Silage Processing Score
% of starch passing
through a coarse screen
(>4.75 mm)
Processing
Rank
Greater than 70%
Optimum
70% to 50%
Average
Less than 50%
Inadequately
processed
Mertens, 2003

15. 4.75 mm is 1/5 of an inch

16. Thumb Rules for Assessing the
Degree of Processing
4.75 mm



> 95% of kernels cracked
(70% equal to or smaller
than 1/3 to ¼ kernel size)
Nicking and crushing are
not enough
Cob should be broken to >8
pieces
diameter hole
These pieces would
Not pass through a
4.75 mm hole….
Thus, they are not processed enough!
L. Kung, Jr., University of Delaware

17. Separate Kernels from Forage in a
Bucket of Water to Assess Kernel Processing
Kung, 2001

18. Post
Processor?
L. Kung, Jr., University of Delaware

19. The Goals of Making Silage
Front-end
Back-end
Rapid preservation for maximum
recovery of nutrients
Continued preservation of nutrients
and excellent “shelf life”

20. Microbes at work in silage – silage
making is like a war – good bugs must win!

“Good bugs”

Lactic acid bacteria
heterofermentative
 homofermentative


“Bad bugs”
Yeasts
 Molds
 Clostridia
 Enterobacteria

Kung, 2001

21. Conditions
Front end fermentation
No Air
sugars
Back end storage
No Air
Stable, high quality
lactic acid
acetic acid
pH
> 45 C
35 C
Days of Ensiling
Kung, 2001

22. However…

A good front end fermentation does not
automatically lead to stability during storage
and feed out (backend)

A high concentration of lactic acid and/or low
pH alone does not automatically equate to a
stabile if silage is exposed to air

23. Ideal Fermentation but Poor Storage Conditions
Front end fermentation Back end storage
No air
Exposure to Air
sugars
lactic acid
acetic acid
pH
>120 F
Days of Ensiling
Kung, 2001
105 F

24. The “Domino Effect” From Air
on Aerobic Spoilage – Bad Bugs
Silage is exposed to air
Yeasts ‘wake up’ and degrade lactic acid
Numbers of yeasts increase
Highly degradable nutrients are destroyed
Heat is produced
pH increases
Molds/bacteria ‘wake up’ causing
further spoilage
More heating
Massive spoilage
L. Kung, Jr., University of Delaware

25. The Negative Relationship Between
Number of Yeasts and Aerobic Stability
200
Hours
Of 160
Stability
Before
120
Spoilage
o o
o
o
80
o
o
o
o
o
o
40
0
1000
Kung, University of Delaware
o
o
o
10000
100000
Yeast, cfu/g
o
o
1000000

26. Changes in DMI When Heifers are Fed
Aerobically Spoiling Feed
Der Bedrosian et al., 2012
a
b
107,151 yeast/g

27. Undesirable Clostridial Fermentation
Front end fermentation
Back end storage
Poor quality forage
High NH3 and butyric acid
Forage too wet
Low sugars
Clostridia
pH
sugars
acetic acid
lactic acid
>120 F
105 F
Days of Ensiling
butyric acid

28. Silo Filling
•Fill quickly
•Pack tightly
•14-16 lb DM/ft3 CS
(225-260 kg DM/m3)
•15-17 lb DM/ft3 AS
(240-270 kg DM/m3)
•6-8 inch (15-20 cm)
layers
•Heavy tractors

29. Plastic on the Sidewalls
Greenfield, 2003

30. Cover With Plastic and Tires
Immediately




White plastic better than
black
6 is better than 4 mil
Small bunks – consider 2
layers? (thin layer on
bottom is best)
More weight on
seams/edges
L. Kung, Jr., University of Delaware

31. Oxygen Barrier Plastics
Kung and McDonell, 2005

32. No Chia-Pet Covers!!!
Kung, 2007

33. Check the teeth on your baggers
Sharp teeth =
-faster and tighter bagging
-cleaner cuts on forage (less juicing)
L. Kung, Jr., University of Delaware

34. Keep Plastic Down at the
Feeding Face
Kung, 2006
Kung, 2006

35. Face Management
- Remove a minimum ??? inch/d
- Remove more in hot weather and for
drier/poorly packed silages
- Keep face clean, minimize face damage
- Knock down only enough silage to feed

36. “The Management Disconnect”
This farm was so happy that they were using a face shaver!
Face Shavers
 (+) Most useful when density
is low and/or feed rate is slow
 May save 3% in DM
 Savings in animal
performance?
 (-) Longer feeding time
L. Kung, Jr., University of Delaware

37. Microbial Inoculants Can Improve Silage
Fermentation and Aerobic Stability

Help at the Front – Homolactic acid bacteria




Help at the Back – Lactobacillus buchneri




Faster fermentation
Reduce clostridia
Improved DM/energy recovery
Improved aerobic stability
Fresher feed
Less spoiling
Dual purpose – Combination of the above

38. Approaches For Using Silage Inoculants –
Tools For Maintaining Good Fermentations
1. Preventing a clostridial fermentation
- wet alfalfa and grasses
- quick attainment of a low pH
- conventional homolactic acid bacteria
2. Improving aerobic stability
- HMC and corn silages
- L. buchneri products
3. Making a good fermentation better
- improvements in DM recovery
Modified from Muck 2008

39. General Inoculant
Recommendations

By crop




Alfalfa and grasss -> Ho* (>40% DM -> LbC**)
Corn silage -> Ho or LbC (if aerobic challenges)
HMC -> LbC
By DM


< 30% DM -> Ho (avoid LB)
> 40% DM -> LbC
*Ho = homolactic acid bacteria based additive
**LbC = L. buchneri + homolactic acid bacteria

40. Managing Your Inoculants

Calibrate applicators frequently

Optimize distribution

Liquid applied is better in drier (>40% DM)
forages

Do not mix inoculants with hot water

Keep water temp in tanks < 95-100 F

41. Numbers of Viable Bacteria Were Lower in
Tanks with High Water Temperatures
r2 = 0.39
P < 0.01
16
Windle and Kung, University of Delaware, 2013
27
38
49

42. Summary





Forage quality and silo management have
profound effects on net farm income
Harvest forage crops at optimum maturity
Follow best management practices for
processing and storage
Use tools available to measure standards
Use inoculants best suited for your needs

43. THANK YOU!!!!
LKSILAGE@UDEL.EDU
http://ag.udel.edu/anfs/faculty/Kung.html