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Lime-treated corn stover: How to
do it and its feed value
Dave Combs
University of Wisconsin-Madison
Higher yields come with more residue which can be used for feed
Sustainable removal creates a second crop for farmers
Courtesy of Steve Petersen, Monsanto Company
Livingston County, IL 28 May 2010
Strip till corn after corn
2009 corn yield 230 bu/ac
Alkali treatment of crop residues
• How to do it
• Safety issues
• Feeding trial
results
Pre-treated lignocellulosics for livestock:
Potentially more food and energy from existing cropland
Distillers
grains
Alkali treatmen
t
Treated
Stover
Source: modified from Cecava, ADM
Corn-belt Stover Production
Stover Production
Million Metric tons
% of U.S. total
Iowa
Illinois
Nebraska
Minnesota
Indiana
Wisconsin
36
31
23
19
15
8
18.3
15.8
12.0
9.9
7.8
4.1
Six state total
132
67.8
U.S.total
196
State
Source USDA. Assumes average harvest index of 0.5 & 9.2 billion bushels
Alkali treatment of crop residues is not
a new idea
Alkali treatment processes:
NaOH
NaOH + CaO
Ammonia
Advantages of Lime treatments over
NaOH and Ammonia
Cost (Chemical cost $20-30/ton of treated feed)
Safety (less caustic than NaOH)
Environmental (Ca has less impact on
soils than Na)
Lime Production Process
Combustion
1800° F
Limestone
Calcium carbonate
CaCO3
Add water
Quicklime
Hydrated Lime
CaO
Ca(OH)2
Calcium oxide
StoverCal O™
Calcium hydroxide
StoverCal H™
Quicklime or Hydrated lime can be used to treat corn stover
Limestone is not effective.
StoverCal O and StoverCal H are trademarked products of MS Lime
Quicklime vs Hydrated Lime
• Active chemical is calcium hydroxide (Ca(OH)2)
• Quicklime reacts with water to form Hydrated Lime
CaO + H20
Ca(OH)2 + Heat
• Quicklime or hydrated lime can be added to stover in
dry form or in water slurry. ADDITIONAL WATER is
needed to bring the final crop residue mixture to 50%
moisture or greater to optimize the reaction.
• Reaction takes at least 5-7 days
How Does It Work?
Alkaline Processing Disrupts Lignocellulosic Structure
Electron micrographs courtesy of MS Lime
Safety issues with Quicklime (CaO)
• If making slurry add Quicklime to large volume of
water and do it slowly to avoid boiling and/or
rupture of containers
• Store quicklime in dry locations.
• Worker safety: Quicklime dust will cause severe
irritation or burning of eyes, skin, respiratory and
GI tract
•
•
•
•
Dust will react with perspiration on skin.
Do not inhale dust.
Eye protection needed/do not wear contact lenses
Wash with soap and water to remove dust.
On-farm lime-treatment of corn stover
• Stover chopped to reduce particle size (3 to 6 “ screen) and increase surface
area.
• Add 5% wt:wt dry CaO and water to create Ca(OH)2 , or add Ca(OH)2 directly.
• Add water to make 50% DM feedstock.
• Store in Ag bags or bunker for at least 7 days
• Used in cattle feed as a replacement for corn grain and/or forage.
Stover Processing
Stover bales tub ground and pre-treated.
Stover ground in commercial grinder fitted
with 6” round-hole screen.
Lime slurry applied at discharge using patent
pending application system. Lime applied at
5% of dry weight of stover.
Back hoe used to pack treated stover in bunker
Stover stored for at least 7 days before feeding
Pre-treated stover added to ration
Source: ADM Commercial Demonstration Trials at Woodbine and Homestead, Iowa
Source: McCabe, www.farmprogress.com, Dec 2012.
Practical
application
Grinding
Adding CaO or
Ca(0H)2
Adding Water
Weight measures
Storage options
The Recipe to make 50% DM treated stover
Water
Stover DM
Lime
1000 lb
950 lb
50 lb
2000 lb (as fed) treated stover
Dry baled stover (90% DM)
As fed stover (950 ÷ .90)
Added water 1000 lb – (1055-950)
Lime
1055 lb
895 lb (112 gallons)
50 lb
2000 lb (treated stover)
To treat 50 tons of 90% DM Stover you need 10,600 gallons of water!
Source: Leubbe, Shreck, Nebraska Dept Anim. Sci. 2011
Composition and digestibility of Stover Diets in Steers
(Shreck et al. 2013 NE Beef Cattle Report)
Ingredient, % of DM
Dry rolled corn
Roughage
Untreated corn stover
CaO treated corn stover
WDGS
Supplement
Control
46
10
0
0
40
4
Untreated Stover
31
0
25
0
40
4
Treated Stover
31
0
0
25
40
4
Diet Intake and Digestibility
DM intake, lb/d
DM digestibility, %
21.6
70.3a
22.9
63.2b
20.7
74.5a
NDF intake, lb/d
NDF digestibilty, % of NDF
4.8c
43.9b
8.1a
44.8b
6.8b
68.1a
Renewed interest in alkali treated crop residues
Biomass
to
animal
feed
–
Rather than sending corn to animal
feed, can we replace corn starch
another paradigm
with treated biomass to produce a
balanced livestock ration?
If we can, less corn is fed to
animals, more is available for
processing and just as much meat
is produced
Treated
Biomass
DDG
Starch and Biomass
By treating and feeding
biomass to ruminants, we feed
the animals a diet similar to
their historical rations and
likely reduce cost to the
producer
Added benefit: Starch and
biomass come from same land
Source: Cecava, ADM
One approach: Utilizing distillers grains and treated stover as a
‘Corn Replacement Feed’ (CRF)
Distillers
grains
Alkali treatmen
t
Treated
Stover
Source: Cecava, ADM
IA State Study: Using Treated Stover and Distillers
Grains as a ‘Corn Replacement Feed’ in Beef Feedlot Diets
Ingredient % DM
Corn
Ration
CRF
Ration
Corn grain
Untreated corn stover
Ca(OH)2 treated corn stover*
70
5
0
Modified distillers grains
20
35
0
20 “CRF”
40
Supplement
5
5
*ag bag stover with alkaline treatment.
Steers fed either (1) Grain Diet or (2) CRF Ration for entire 183 day trial.
Russell et al. 2011, Iowa State Animal Industry Report. A.S. Leaflet R2586
Corn can be profitably displaced in ruminant rations with processed biomass
and corn-ethanol coproducts such as distillers grains
30 bushels less
corn versus high
grain control
ration
Weight gain, lb/d
4.50
Distiller’s
grains
4.00
3.50
3.90
3.84
$90.54
$118.58
Returns per
Steer
3.00
2.50
2.00
1.50
1.00
Processed
stover
0.50
0.00
Distiller’s
grains
Corn Ration
CRF Ration
Processed stover and co-products displaced grain and roughage
Similar cattle performance and better returns per steer
Russell et al. 2011, Iowa State Animal Industry Report. A.S. Leaflet R2586 (Source: Cecava ADM AFR 09-20 )
University of Nebraska Feeding Trials: Replace about
10-15 % units of corn with treated stover in feedlot
diets (2011 NE Beef Cattle Report)
Ingredient, % of
DM
Dry rolled corn
Roughage
Untreated corn
stover
CaO treated
corn stover
WDGS
Supplement
Control
46
10
Untreated
Stover
36
0
Treated Stover
36
0
0
20
0
0
40
4
0
40
4
20
40
4
Shreck et al. 2011 NE Beef Cattle Report
Lime-treated Stover for Feedlot Beef
Cattle
• Can be fed to yearlings through finishing
• 2:1 ratio of Distillers grains and treated stover
(CRF) can replace up to half the ground corn in
feedlot diets (Iowa State University results)
• 10 to 15% units of corn grain can be replaced
with lime-treated stover without affecting
DMI, ADG or feed efficiency in background
and finishing feedlot diets. (University of
Nebraska results)
Treated Stover for Lactating Dairy
Cattle
• Purdue University: Processed corn stover as a
replacement feed for corn silage in lactating
dairy cattle.
• UW-Madison and USDA-ARS: Effect of CaOtreated corn stover on dairy cattle
performance when substituted for corn grain.
Purdue Research
(Donkin et al., 2012 ADSA meeting abstracts)
• Control diet containing 37.5% of diet DM as
corn silage
• CaO (5%) treated stover inclusion at 12.5 or
25% of ration DM in place of corn silage.
Treated Stover replaced 1/3 or 2/3 of diet corn
silage.
Purdue University Trial Results
• Mid-lactation Holstein dairy cows
• Stover replaced part of the corn silage
• Short term trial to test palatability - diets were fed for 21 days
Control
Treated stover
% of dry ration wt
DMI, lbs/d
Milk, lbs/d
Efficiency
% Milk Fat
% Milk Protein
% Milk Lactose
0
52.9
64.5
1.22
3.92
2.99
4.71
“On-farm” treated
12.5
49.3
61.0
1.24
3.64
3.06
4.62
25
47.7
63.6
1.33
4.00
3.06
4.63
Extrusion treated
12.5
48.9
65.1
1.33
3.89
3.13
4.63
25
49.3
67.1
1.36
3.98
2.96
4.5
 Cows consumed less feed when treated stover was fed
 Cows fed extruded stover were more efficient than control cows
 Composition of milk (fat, protein, lactose) similar
 Results are promising for advanced processing being superior to “on-farm”
USDA-ARS and UW-Madison Research
(Cook, Combs and Hall 2013)
• Objective: Determine the production and
digestion responses of lactating dairy cows to
dietary substitution of CaO- treated corn
stover for corn grain
• 64 cows
• Four treatments:
– Control ( 19% Corn, 0 stover)
– 4, 8 or 12 % of diet DM as CaO treated stover
– Corn stover replaced corn grain
Wisconsin Dairy Trial
Trial used “on-farm” treated stover made by batch processing in mixer wagon
Question: Can treated stover be used as a corn grain substitute for lactating cows?
The batch “recipe”
LBS
GROUND STOVER
WATER
1111
939
CALCIUM OXIDE
TOTAL
50
2100
Diets: Substitution of corn grain with
CaO-treated corn stover
Item, % of diet DM
CaO stalklage
Dry ground corn
Corn silage
Alfalfa silage
Distillers grains
Soybean meal
Soyhulls
Vit & Min
Limestone
Control
0
19
32
20
10
10.7
4.4
2.5
1.4
4 stover
for corn grain
4
15
32
20
10
11.2
4.4
2.5
0.9
8 stover
for corn grain
8
11
32
20
10
11.6
4.4
2.5
0.5
12 stover
for corn grain
12
7
32
20
10
12.1
4.4
2.5
0
(Cook, Combs and Hall, 2013)
Substitution of corn grain with CaOtreated corn stover for lactating cows
Item
CaO stalklage
Dry Ground
Corn
Dry matter
intake, lb/d
Milk yield, lb/d
Milk fat, %
3.5% FCM, lb/d
Control
4 stover
for corn grain
8 stover
for corn grain
12 stover
for corn grain
0
4
8
12
19
15
11
7
59.0a
92.9a
4.31a
105.6a
56.8b
90.0b
4.18ab
101.3a
53.7c
86.8c
4.06b
95.5b
51.7d
81.4d
4.05b
90.8b
(Cook, Combs and Hall, 2013)
Substitution of corn grain with CaO-treated corn
stover for lactating cows
120
3.5% FCM, lb/d
100
80
60
40
20
0
0
2
4
6
8
10
12
Inclusion rate of CaO treated Stover, % of diet DM
(Cook, Combs and Hall, 2013)
14
Substitution of corn grain with CaOtreated corn stover for lactating cows
Item
CaO stalklage
Dry Ground
Corn
Dry matter
intake, lb/d
NDF %
NFC%
Starch%
Control
4 stover
for corn grain
8 stover
for corn grain
12 stover
for corn grain
0
4
8
12
19
15
11
7
59.0a
56.8b
53.7c
51.7d
25
45
29
27
43
26
30
41
24
32
38
21
(Cook, Combs and Hall, 2013)
Lime-treated Stover for Lactating Dairy
Cattle
• Purdue research: CaO treated corn stover
replaced 1/3 or 2/3 of diet corn silage without
affecting milk yield or intake of cows
producing approximately 65 lb milk/d
• Wisconsin research: Milk and FCM yield
declined linearly as CaO-treated stover
replaced corn grain in diets of cows producing
approximately 100 lb of 3.5% FCM
The bottom line
• Quicklime or hydrated lime can significantly
improve fiber digestibility of corn stover.
• Treatment process requires tub grinder or
chopper, adequate water supply and bunkers
or ag bags for storage.
• For growing cattle, CaO treated stover can
replace a significant amount of corn grain,
especially if fed with distillers grains.
The bottom line: continued
• CaO-treated stover may be a viable alternative
for up to 2/3 of ration corn silage for mid to
late lactation cows.
• CaO-treated stover does not appear to replace
corn grain in high producing cow diets as
effectively as for feedlot steers.
• CaO-treated stover as forage for heifers?
Thank You!
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