Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
The Final Step: Covering the Bunker
Michelle Windle, PhD Forage Products and Dairy Technical Service Specialist
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Topics • Fermentation 101
• Spoilage: A brief overview
• Silo covers – Plastic and beyond
• Preventing spoilage from happening
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Silage Microbiology 101 • In the field, plants are covered in microorganisms. Per gram:
• Microorganisms have ideal environments for growth – Some need oxygen; some need a lack of oxygen
– Some need a low pH; some need a high pH
– Typically, the “bad guys” like a high pH and lots of oxygen
– Therefore, the goal of ensiling: a low pH and no oxygen
Aerobic bacteria >10,000,000
Lactic acid bacteria ~1,000,000
Enterobacteria ~1,000,000
Yeasts ~100,000
Molds ~10,000
Clostridia ~10,000
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Aerobic Phase
Up-Front Fermentation
Storage Feedout
Phases of Ensiling:
Aerobic Aerobic
Begins once silage is exposed to oxygen;
Also known as “spoilage”
• Crop is still respiring, using sugars and proteins
• Aerobic bacteria are alive and well, and they use sugars and protein; produce heat
• Fermentation cannot begin until oxygen is gone
Begins once the silo is covered and oxygen is gone;
Continues so long as oxygen is absent
Oxygen
Anaerobic
pH acids
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How does the initial aerobic phase affect feedout stability?
Prolonged aerobic phase
Less sugars for
fermentation
Less acetic acid;
Higher silage pH
More yeast More
spoilage
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
What does spoilage look like?
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How spoilage occurs: A “Domino Effect”
Silage is exposed to air
Oxygen wakes yeasts up; they grow in numbers and degrade lactic acid raising pH
Highly degradable nutrients ($) are destroyed; loss of DM ($)
Heat is produced
The increase in pH “wakes up” molds/bacteria, causing massive spoilage
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Spoilage changes the nutrient profile of feeds
Item Fresh TMR Spoiling TMR
pH 4.16 5.17
WSC (Sugars), % 2.46 1.85
Lactic acid, % 4.17 2.59
Acetic acid, % 0.97 0.64
Ethanol, % 5.82 6.07
Yeasts, cfu/g 107,151 66,069,345
2013 Windle and Kung
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Summary of Negative Effects of Spoilage • DM losses
• Heated feed
• Nutrient losses
• Decreased digestibility
• Decreased feed quality/value
• Decreased palatability and intake
• Reproductive problems
• Sick animals (potential for toxins)
• Reduced milk production
• Lost money!
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How to avoid spoilage: A cheat sheet
• Harvest at the proper moisture level
• Pack to achieve optimum density
• Cover promptly, with good quality plastic
• Manage the silo
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How to avoid spoilage: A cheat sheet
• Harvest at the proper moisture level
• Pack to achieve optimum density
• Cover promptly, with good quality plastic
• Manage the silo
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How does moisture at harvest affect spoilage almost a year later, during feedout?
• Porosity: A measure of the air spaces
• A lower number (<0.40) is good
• Porosity increases…
– As density decreases
– As DM content of the crop increases
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
What is the ideal moisture content?
Crop DM Content Moisture Content
Corn Silage 32 – 35% 65 – 68%
Snaplage 58 – 64% 36 – 42%
High-Moisture Corn 64 – 72% 28 – 36%
Haylage 40 – 45% 55 – 60%
Baleage 45 – 55% 45 – 55%
Ryelage/Wheatlage 35 – 40% 60 – 65%
Note that these are dependent on the silo structure – For example, horizontal bag silos are typically drier than bunkers
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How to avoid spoilage: A cheat sheet
• Harvest at the proper moisture level
• Pack to achieve optimum density
• Cover promptly, with good quality plastic
• Manage the silo
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
• Pack tightly
• 6-8 inch layers
• Heavy tractors
• Keep tractor on the pile
Packing well excludes oxygen and jump-starts fermentation
Pack tractor wt ÷ 800 = tons/hr
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Not enough weight!
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How to avoid spoilage: A cheat sheet
• Harvest at the proper moisture level
• Pack to achieve optimum density
• Cover promptly, with good quality plastic
• Manage the silo
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Silos that are not promptly sealed….
• Have less silage in them once opened (poor DM recovery due to prolonged aerobic phase and inefficient fermentation)
• Have less sugars for fermentation
• Have a higher pH – More prone to Clostridia
• Have less total acids produced
– Silage acids are healthy! – Lactic acid has great DM recovery – Acetic acid prevents spoilage
• Have more spoilage yeasts
• Are more prone to spoilage upon opening
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Silo Covers: What’s out there? • Plastic covers
– Standard Polyethylene (PE) – Oxygen barrier – Two-in-one
• One-step • Reinforced one-step • Both bonded together • Both rolled together
• Reusable tarps
• Edible covers
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Polyethylene plastic: Background
• Use of black and white (PE) plastic probably originated in Europe as repurposed fumigation plastic
• Tires help to exclude oxygen and prevent it from spreading if there is a hole
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
What have we learned?
• Thicker is better (especially on baleage) – Less oxygen permeability
– More puncture resistant
• Color matters for UV purposes
• Oxygen-barrier technology is useful and worth the extra work – Oxygen barrier plastics have an additive – polyamide/EVOH
– Less oxygen gets through the plastic
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
0
5
10
15
20
Control Treated
%
DM Losses in Bunker Silos
0
2
4
6
8
10
Control Treated
%
DM Losses in Balage
02
4
68
10
12
Control Treated
%
Inedible Silage
0
50
100
Control Treated
ho
urs
Aerobic Stability
Oxygen barrier plastics: Meta analysis of 51 trials (Wilkinson and Fenlon, 2013)
B+W B+W with OB
B+W B+W with OB
B+W B+W with OB
B+W B+W with OB
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Black and White Plastic with OB properties • Pros:
– Saves labor
– Thicker plastic
– May be reinforced with cross-hatching fibers
– Oxygen barrier
• Cons: – May be pricey
– May lack the “cling” factor that eradicates oxygen quickly
– May flap in the wind during feedout if face isn’t managed properly
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Two-in-One Covers • May be physically connected, or simply
rolled together
• Appeal: Convenience
• If connected, do they actually separate?
• Research?
• Quality of the “oxygen barrier” film?
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Not All “Oxygen Barrier” Plastics are Equal
23.2 84 154 545 650
2691
4039 4146 4304
6388
8303 8769
0
2000
4000
6000
8000
10000
OTR
, cc/
m2
/day
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
SiloStop (23 cc/m2/d)
KSI (154 cc/m2/d)
Plastic Comparison
Polydress (8769 cc/m2/d)
HiTec (8303 cc/m2/d) Clear Up North (6388 cc/m2/d)
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Reusable tarps
• Woven or nonwoven
• Pros – Less waste – No tires (may be less labor) – Stronger than plastic, protecting
against animals/weather – Can save money
• Cons – Pricey up-front investment – In winter, can be a challenge – People may cut/ruin them
www.farmshow.com
www.securecovers.co.uk
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Edible coverings
• Plastic covers are: – Convenient and effective
– Wasteful: Non-biodegradable plastics (including silo plastics) make up as much as 30% of municipal solid waste in the US
– Labor-intensive
– Expensive
• Edible covers may alleviate all of this; may bond to forage particles making tighter seal
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Edible silo covers
• What are they made of? – Starch/salt mixture, covered with a thin layer of molten paraffin wax
– Fat
– Peanut butter
– Apple pulp
– Molasses
– Small grains
– Sod
– Sawdust
– Chopped Straw
– Composted manure solids
– Zein proteins
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Reality of edible covers • Labor intensive (need to mix the components, heat them while
mixing, etc.)
• New equipment required (i.e. a commercial concrete pump)
• May require ingredients to be held/applied at high temperatures
• Uneven application
• Edible cover may be edible by pests, too (vermin and/or bacteria)
• Cost
• Ingredients may not be good for the rumen (i.e. unsaturated fats)
• Ingredients may take up room in the diet
• How resistant is it REALLY? – Weight of snow
– Slow drizzle over days may degrade it
– May get brittle in the cold and crack, letting oxygen in
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
How to avoid spoilage: A cheat sheet
• Harvest at the proper moisture level
• Pack to achieve optimum density
• Cover promptly, with good quality plastic
• Manage the silo
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Bagging tips
Check bags and covers regularly for holes
Kung, 2004
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Face Management
• Keep face clean
• Knock down only enough silage to feed in a day
• Remove more for drier and poorly packed silages to stay ahead of spoilage
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
• Minimum 6”/d in winter and 12”/d in summer
• Recommended feedout rates for bag silos:
Feed Out at the Proper Rate
Bag Size Winter Rates (ft/d) Summer Rates (ft/d)
8’ 1 2
9’ 1 2.25
10’ 2 2.5
11’ 2.25 2.75
12’ 2.5 3
Ag Bag recommendations
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Additives to help with spoilage:
• Managing already spoiled silage – Dilution (but this may decrease feedout rate and
exacerbate the problem)
– Probiotics/Yeasts?
– Binders?
• Prevention is the best route – After ensiling: Acids
– Before ensiling: Inoculants
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
It’s More Efficient to Treat at Ensiling Then at the Wagon
0
50
100
150
200
250
300
350
400
CS TMR
Hours of Stability
Ctrl LB TMR mate 5 lb/t TMR mate 10 lb/t
Added to TMR
Schmidt and Kung 2006
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Recommendations from Limin Kung:
Should We Inoculate All Silages with L. buchneri?
No!
When is L. buchneri Most Useful?
• Silages with high starch:
HM corn, corn silage, cereal
grain silages
• Poor bunk life, heating TMR
issues
• Silages with slow feed-out
rates/big faces
• Silages with multiple faces
• Drier silages
• Silage that will be moved
• Summer feed
• Prolonged storage
• Silages that are poorly
packed
• Any silage with oxygen
challenges
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
In Summary, The Ideal Silo….
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
0
5
10
15
20
25
10 13 15 16 17 20
Is packed well… D
M lo
ss, %
Packing Density Lb/cu ft. (Ruppel, 1992)
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Uses stretch
marks to help
with packing…
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Has only one face…
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Manages the plastic during feedout
• Keep the face down on the leading edge
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Fits the Structure…
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Can be driven over from all
directions
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Summary
• Spoilage is best measured/identified by yeast counts and temperature
• To prevent spoilage, focus on – Limiting oxygen – Limiting yeast growth – Management – Using the best inoculant
Stepping Forward December 9 & 10 | Dairy Summit 2015 | Baraboo, Wis.
Thank you!