• TABLE OF CONTENTS
HIDE
 Introduction
 Composition of by-products
 Nutritional value - dry by-pro...
 Storage and feeding - wet...
 Economic value of distillery...
 Figure 1 - By-products of alcohol...
 Table 1 - Nutrient contents of...
 Table 2 - The energy, crude protein,...
 Table 3 - Economic value of distillers...
 Table 4 - Utilization of wet stillage...














Group Title: Department of Animal Science research report - Florida Agricultural Experiment Station ; AL-1981-9
Title: Nutritional value of distillers by-products
CITATION PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00073130/00001
 Material Information
Title: Nutritional value of distillers by-products
Series Title: Department of Animal Science report
Physical Description: 9 leaves : ill. ; 28 cm.
Language: English
Creator: Kunkle, William, 1947-
University of Florida -- Dept. of Animal Science
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1981
 Subjects
Subject: Distillers feeds -- Florida   ( lcsh )
Distilling industries -- By-products -- Florida   ( lcsh )
Animal nutrition   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: William E. Kunkle.
General Note: Caption title.
General Note: "September, 1981."
Funding: Animal science research report (University of Florida. Dept. of Animal Science) ;
 Record Information
Bibliographic ID: UF00073130
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 80952288

Table of Contents
    Introduction
        Page 1
    Composition of by-products
        Page 2
    Nutritional value - dry by-product
        Page 2
    Storage and feeding - wet by-products
        Page 3
    Economic value of distillery by-products
        Page 4
        Page 5
    Figure 1 - By-products of alcohol production
        Page 6
    Table 1 - Nutrient contents of corn, DDGS, DDG, DDs, and soybean meal
        Page 7
    Table 2 - The energy, crude protein, and amino acid requirements of swine and composition of feeds
        Page 8
    Table 3 - Economic value of distillers dried grains (dry basis)
        Page 9
    Table 4 - Utilization of wet stillage from a unit producing 100 gallons of alcohol daily
        Page 9
Full Text



Department of tAnimal Science
Report AL-1981 9
September, 1981


- 1 -


NUTRITIONAL VALUE OF DISTILLERS BY-PRODUCTS


William E. Kunklel

The production of ethanol from grains is a two-step process. The ground
grain is cooked in a water slurry to gelantinize the starch and then microbial
amylases are added to cleave the starch to glucose. In the second step, a
yeast is added to ferment the glucose to ethanol.

The ethanol is separated from the slurry by distillation. The whole stil-
lage remains after distillation of fuel alcohol and contains 6 to 12% solids.
Approximately 60% of the solids can be screened out of the whole stillage,
(wet grains), and 40% of the solids remain in suspension (thin stillage).
Figure 1 schematically illustrates the processing procedure for ethanol produc-
tion.

The definition of several of the by-products are as follows:

Dry By-Products

DDGS Distillers Dried Grains with Solubles includes the dried grains
(screened by-products) and the dry solubles.
DDG Distillers Dried Grains includes the dried coarse (screened) by-
product.
DDS Distillers Dried Solubles includes the dried soluble and suspend-
ed fractions of the by-product.


CDS Condensed
fractions
water),


Distillers Solubles includes the soluble and suspended
of the by-product condensed to a semi-solid (25-40%


Wet By-Products


Whole Stillage Fermentation residue after distillation containing
6-12% dry matter; approximately 200 Ibs (24 gallons)
containing 16 Ibs dry matter/bushel of corn processed.
Wet Grains grains and larger particles separated from whole stil-
lage by screening, filtering or pressing, containing
25-40% dry matter; approximately 10 lbs dry matter/
bushel of corn processed is recoverable by screening.
Thin Stillage suspended and soluble materials in the liquid after
removing wet grains contain 2-5% dry matter; approxi-
mately 6 lbs dry matter/bushel corn processed remains
in the liquid.



1Extension Beef Specialist, Department of Animal Science, University of Florida.






-2-


Composition of By-Products
A bushel of corn (56 pounds) yields approximately 2 gallons of ethanol
and 16 pounds of dry by-product. Corn contains approximately two-thirds starch
that is converted to alcohol leaving the other one-third (16 pounds) in the
whole stillage. The protein, fiber, fat and ash content of the by-product is
concentrated by approximately three times the level in corn grain. The nutrient
content of several corn distillers by-products is shown in Table 1.

The fiber content of DDGS is increased, but the net energy content is
similar to corn since the fat content is increased.

Nutritional Value Dry By-Product
The value of dried distillers by-products has been researched extensively
over the past 30 years. Distillery by-products contain 25-30% crude protein,
but their use as a major protein supplement is limited mainly to ruminants.
Low levels of essential amino acids (lysine, methionine, tryptophan) limits
the use of distillery by-products in poultry and swine feeds.

Beef. Distillery by-products (dry) used as protein supplements in beef
diets have given results similar to soybean meal and cottonseed meal in numerous
trials. Recent research has shown that a mixture of 93% DDG and 7% urea result-
ed in cattle performance equal to a soybean meal supplement, when fed at equal
protein levels and the mixture was less expensive. A smaller proportion of DDGS
protein is degraded in the rumen allowing more urea to be utilized by the rumen
bacteria, DDGS has a higher economic value for lighter calves that require na-
tural protein supplements but a lower value for finishing cattle that can uti-
lize higher levels of urea to provide supplemental nitrogen.

Dairy, Several trials have shown that DDGS is a good protein source for
milking cows. Cornell research has shown that DDGS can replace soybean meal
on a protein equivalent basis in dairy rations without a significant change
in milk production. The wet by-products need further research to confirm
their use in dairy rations. An additional benefit of DDGS is their 9.3% fiber
content that may be of special significance when fiber sources are in short
supply, In high grain diets, DDGS have been shown to maintain fat test better
than soybean meal.

Swine, The value of distillery by-products as a protein source for swine
is limited by the low level of lystne (Table 2). The lysine comprises only
2,2% of the protein in DDGS but a 50 lb pig needs a protein containing 4.4%
lysine in a 16% protein diet to meet its requirement, Utilizing DDGS to pro-
vide a major portion of the protein in the diet will result in a reduced
growth rate unless supplemental lystne is added.

Growing and finishing pigs fed diets containing 10% DDGS had performance
similar to pigs receiving a control diet but performance was decreased when
20% was added to the diet. Gestating sows fed.diets containing up to 40% DDGS
performed similar to those fed a control diet, Distillers Dried Solubles have
a hiher lystne content and lower "Ter content than DDG (Table 1) and are better
utilized as a source of protein in swine diets.






-2-


Composition of By-Products
A bushel of corn (56 pounds) yields approximately 2 gallons of ethanol
and 16 pounds of dry by-product. Corn contains approximately two-thirds starch
that is converted to alcohol leaving the other one-third (16 pounds) in the
whole stillage. The protein, fiber, fat and ash content of the by-product is
concentrated by approximately three times the level in corn grain. The nutrient
content of several corn distillers by-products is shown in Table 1.

The fiber content of DDGS is increased, but the net energy content is
similar to corn since the fat content is increased.

Nutritional Value Dry By-Product
The value of dried distillers by-products has been researched extensively
over the past 30 years. Distillery by-products contain 25-30% crude protein,
but their use as a major protein supplement is limited mainly to ruminants.
Low levels of essential amino acids (lysine, methionine, tryptophan) limits
the use of distillery by-products in poultry and swine feeds.

Beef. Distillery by-products (dry) used as protein supplements in beef
diets have given results similar to soybean meal and cottonseed meal in numerous
trials. Recent research has shown that a mixture of 93% DDG and 7% urea result-
ed in cattle performance equal to a soybean meal supplement, when fed at equal
protein levels and the mixture was less expensive. A smaller proportion of DDGS
protein is degraded in the rumen allowing more urea to be utilized by the rumen
bacteria, DDGS has a higher economic value for lighter calves that require na-
tural protein supplements but a lower value for finishing cattle that can uti-
lize higher levels of urea to provide supplemental nitrogen.

Dairy, Several trials have shown that DDGS is a good protein source for
milking cows. Cornell research has shown that DDGS can replace soybean meal
on a protein equivalent basis in dairy rations without a significant change
in milk production. The wet by-products need further research to confirm
their use in dairy rations. An additional benefit of DDGS is their 9.3% fiber
content that may be of special significance when fiber sources are in short
supply, In high grain diets, DDGS have been shown to maintain fat test better
than soybean meal.

Swine, The value of distillery by-products as a protein source for swine
is limited by the low level of lystne (Table 2). The lysine comprises only
2,2% of the protein in DDGS but a 50 lb pig needs a protein containing 4.4%
lysine in a 16% protein diet to meet its requirement, Utilizing DDGS to pro-
vide a major portion of the protein in the diet will result in a reduced
growth rate unless supplemental lystne is added.

Growing and finishing pigs fed diets containing 10% DDGS had performance
similar to pigs receiving a control diet but performance was decreased when
20% was added to the diet. Gestating sows fed.diets containing up to 40% DDGS
performed similar to those fed a control diet, Distillers Dried Solubles have
a hiher lystne content and lower "Ter content than DDG (Table 1) and are better
utilized as a source of protein in swine diets.






- 3 -


Poultry. The low quality of DDGS protein also limits its use in poultry
diets. Lysine, methionine and tryptophan have been shown to be limiting.
Levels of DDGS up to 10-20% of the diet have been added to poultry rations
without depressing performance in several trials.

Storage and Feeding Wet By-Products

The increased costs of energy have increased the interest in feeding wet
distillers by-products, especially if the by-products are available on the
farm. Approximately 40% of the energy used in the distillery process is used
to dry the by-product.

A major problem in feeding the wet distillery by-products is storing them
until feeding. The pH of the by-products from most processes is 3.7 to 4.0
because sulfuric acid is added prior to the fermentation phase to prevent the
growth of undesirable microorganisms.

The low pH prevents bacterial fermentation or ensiling but the by-products
will mold rapidly when exposed to air. The storage and feeding of the whole stil-
lage, wet grains and thin stillage will be discussed separately, since each has
different limitations.

Whole Stillage. The high water content limits its use in rations and makes
settling during holding a problem. The surface will mold rather rapidly, especial-
ly with high temperatures and whole stillage is best utilized when fresh. The
molds are usually on the surface, and excluding air with carbon dioxide or
ammonia can prevent the molding. Propionic acid is also an effective mold inhibi-
tor. Recent research indicates that a small amount of residual ethanol may de-
crease the surface molding. Whole sttllage could also be used to reconstitute
grains or forages. The acidity tn the stillage will likely need to be neutraliz-
ed with lime, ammonia or another base, to allow fermentation after reconstitution.

Whole stillage was fed routinely prior to 1950, near the distilleries in
Kentucky,-Garrtgus, Untverstty of Kentucky, reported yearling steers gained up
to 1.9 pounds/day when fed 5/lbs/hd/day of hay and fresh whole stillage free
choice. The steers consumed over 20 gallons of whole stillage daily. Garrigus
concluded growing cattle required 4-5 pounds/hd/day of roughage to slow the rate
of passage and eliminate bloat. The cattle also required 2-4 ounces of salt, 1.5-
2 ounces of limestone and 10,000 r.U. of Vitamin A per head daily. Irregular
feeding and sour stillage were cited as causes of digestive upset. Older grow-
thter cattle with more capacity made better gains and the value of stillage de-
clined as the steer approached market weight. The cattle required a month to get
on feed and lost weight the first few days they were fed wet stillage. The long
adaptation period stresses the importance of having a fresh supply available
regularly. The high water content limits the usefulness of a diet high in whole
stillage, for calves or finishing cattle and these diets are best used to grow
yearling cattle or in maintaining beef cows. Limiting whole stillage in the
diet to levels needed to supply the supplemental protein should allow near
maximum gains in growing and finishing beef cattle.

Wet Distillers Grains. The wet grains will mold very rapidly throughout when
exposed to air. The grains should be fed fresh for best results. Storage of wet
grains in a sealed structure gassed with carbon dioxide or ammonia, or treated
with proptonic acid should allow storage of this by-product. Nebraska researchers






- 4 -


have increased the pH by adding lime and this resulted in a fermentation and
ensiling of the wet grains. The fermentation produced high levels of butyric
acid and high levels of butyric acid have resulted in poor consumption with
other silages, but additional research is needed to confirm the feeding value
of the ensiled by-product.

The wet grains are usually 25% or higher in dry matter and can be fed
and handled similar to silage. Nebraska researchers fed wet distiller's
grains containing 25% dry matter at levels up to 64% of the ration dry matter,
and found that yearling cattle performed similar to those receiving a high
corn diet. In this trial wet grains had a feeding value equal to corn on a dry
matter basis delivered to the feed bunk.

Iowa researchers increased the dry matter in whole stillage from 10%
to 18% by allowing it to settle in a tank and removing the top liquid. They
were able to store the drained stillage up to 7 days without noticeable
spoilage but the material contained approximately 1% ethanol.
Thin Stillage. The storage of thin stillage is similar to whole stillage.
Thin stillage has limited value as a feed ingredient unless condensed or con-
centrated. It could be utilized to reconstitute grains or forages or used as
the water source for cattle if settling problems can be overcome. Concentrat-
ing thin stillage in settling ponds or with centrifuges needs further research.

Aflatoxin will be present in by-products of grains that contain aflatoxin
before fermenting. Research shows part of the aflatoxin is degraded but 25-50%
was found in the by-products.

Economic Value of Distillery By-Products

The value of distillery by-products is highest when used as a source of
protein for cattle (Table 3).

DDGS was worth $216,/ton as a protein feed for beef when it replaced soy-
bean meal priced at $300,/ton. However the supplemental crude protein in the
finishing diets of heavier weight cattle could be effectively supplied with
urea based supplements that are less expensive, therefore the $216. protein re-
placement value will be too high for most cattle diets. The comparative economic
values do not consider the costs of storing, handling and feeding the wet by-
products,

Feeding Systems
The dry distillery by-products are readily marketable feedstuffs. The wet
by-products are expensive to haul and the storage period is limited. Wet stillage
could be best utilized for its highest potential value as a protein feed for
dairy and beef cattle. Wet stfllage could also be marketed at a potentially lower
value as an energy feed for dairy and beef cattle, and gestating swine. An exam-
ple of the number of animals required for three systems is shown in Table 4.
The table shows that a large livestock operation will be needed to utilize the
by-product unless it is fed at levels above that needed to meet the protein require-
ments,

Although very little information is available, neither system described for







5-

the growing steer may be optimum. A yearling steer averaging 900 pounds during
the finishing period (700-1100 Ibs.) would consume approximately 20 Ibs. dry
matter. A ration of 3 pounds hay, 1 pound supplement, 8 pounds corn and 8
pounds stillage dry matter (100 Ibs. whole stillage), should not limit gains
and may market the wet stillage at a higher value compared to feeding higher
levels of stillage. This system would require 85 steers to utilize the by-
product from a 100 gallon/day plant.

This is a summary of present knowledge on the utilization of distillery
by-products. More research is needed to determine the best systems of handl-
ing, storing and feeding distillery by-products.







-6-


FIGURE 1. BYPRC








Ferment



Condensed
Solubles Syru
(25-40% DM) %



Dried -. |
Grains Drier


)DUCTS OF ALCOHOL PRODUCTION


Alcohol


le Stillage
(6.5% DM)


Screen & Press
or Centrifuge


Press or centrifuge
Cake (30-45% DM)


Source: Ethanol Production and Utilization For Fuel, University of
Nebraska, Cooperative Extension Service, 1979





-7-


Table 1. Nutrient Contents of

Shelled
Nutrient Corn

TDN, % 91

Crude Protein, % 10

Lysine, % of Protein 2.7

Crude Fiber, % 2.2

Fat, % 3.5

Ash, % 1.2

Calcium, % .02

Phosphorus, % .32


Corn, DDGS, DDG, DDS and Soybean


DDGS

85

29.6

2.5

9.3

8.8

4.9

.10

.95


DDG

83

29.5

2.2

12.8

8.0

2.2

.10

.37


DDS

86

29.8

3.3

4.2

9.8

7.3

.30

1.60


2
Composition reported is tn dry matter,


Meal ,2

Soybean
Meal

82

52.4

6.6

5.9

1.3

6,5

.30

.70


Selected Values from University of Nebraska, Distillers Feed Research
Council and National Research Council


----







-8-


Table 2. The Energy, Crude Protein and Amino Acid Requirements of Swine and
Composition of Feedsa


Requirements Composition
Gestating Soybean b
Nutrient 50 lb. Pig Sow Corn Meal DDGS
Metabolizable d d
Energy 4740c 5760 3325 3485 2790

Crude Protein (%) 16 12 8.8 48.5 27.2

Lysine
% of diet .7 .43 .24 3.18 .60
% of protein 4.4 3.6 2.7 6.6 2.2

Tryptophan
% of diet .12 .09 .05 .67 .19
% of protein .75 .75 .57 1.38 .70

Methionine And
Cystine
% of diet .45 .23 .40 1.40 .90
% of protein 2.8 1.9 4.5 2.9 3.3


aNRC 1979


bDried Distillers Grains with Solubles

CKcal/day


dKcal/kg







- 9 -


Table 3. Economic Value of Distillers Dried Grains (Dry Basis)a


Use of DDG
Protein Energy
Beef $216b ($1.73)c $112 ($.90)

Swine $114 ($ .91) $ 96 ($.77)
Market Price $200 ($1.60)


value calculated using following prices: corn, $3.50/bu.: soybean meal,
$300./ton; dicalcium phosphate, $350/ton
$/ton, dry

c(Value, $/bu )


Table 4. Utilization of Wet Stillage from a Unit producing 100 Gallons
of Alcohol Datlya


Animal
Growing Growing Gestating
Item Steer 'Steer Sow
By-product Use Protein Energy Energy
By-product Level supp. protein 60% dry matter 100% energy
Stillage Dry Matter, Ibs/hd/day 2.5 12 4.5
Stillage Wet, Ibs/hd/day 31.5 150.0 56.8
Stillage Wet, gal/hd/day 3.9 18.8 7.1
No, Animals Required 270 57 151

a100 gallon/day, 40 bu. corn/day, 680 Ibs. stillage D.M., 8500 Ibs. (8%) wet stillage
bgo0 lb. steer, 20 Ibs. D.M. intake

CStillage fed at a level to provide all supplemental protein from a high grain diet
d
tiTllage provides 60% of the daily dry matter intake
eStillage provides 100% of the daily metabolizable energy requirement







- 9 -


Table 3. Economic Value of Distillers Dried Grains (Dry Basis)a


Use of DDG
Protein Energy
Beef $216b ($1.73)c $112 ($.90)

Swine $114 ($ .91) $ 96 ($.77)
Market Price $200 ($1.60)


value calculated using following prices: corn, $3.50/bu.: soybean meal,
$300./ton; dicalcium phosphate, $350/ton
$/ton, dry

c(Value, $/bu )


Table 4. Utilization of Wet Stillage from a Unit producing 100 Gallons
of Alcohol Datlya


Animal
Growing Growing Gestating
Item Steer 'Steer Sow
By-product Use Protein Energy Energy
By-product Level supp. protein 60% dry matter 100% energy
Stillage Dry Matter, Ibs/hd/day 2.5 12 4.5
Stillage Wet, Ibs/hd/day 31.5 150.0 56.8
Stillage Wet, gal/hd/day 3.9 18.8 7.1
No, Animals Required 270 57 151

a100 gallon/day, 40 bu. corn/day, 680 Ibs. stillage D.M., 8500 Ibs. (8%) wet stillage
bgo0 lb. steer, 20 Ibs. D.M. intake

CStillage fed at a level to provide all supplemental protein from a high grain diet
d
tiTllage provides 60% of the daily dry matter intake
eStillage provides 100% of the daily metabolizable energy requirement




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