Understanding Corn Processing Co-products Use in Livestock Feeds
John D. Lawrence, Iowa State University
Darrell Mark, University of Nebraska
Outline
• Trend in corn processing
• Implications for corn prices
• Cellulosic ethanol potential
• Types of corn processing
• Coproducts and nutritional values
• Factors to consider before feeding
• Summary
Corn for Food, Fuel, and Industrial, Million Bushels
0
500
1000
1500
2000
2500
3000
3500
4000
Other Food and Industrial Ethanol
US Ethanol ProductionJune 2006
Status Plants B/Gal
• Operational 102 4.75• Construction 32 3.03• Announced 127 8.21• Potential total 261 15.99
• Potential corn use: 5.3-5.9 B/bu• Some estimates are higher
Source: National Corn Growers Association
Implications for Corn Prices
• Increased demand for corn is expected to:– Increase corn prices– Increase corn acres
• Long run price impact will depend on– Price of oil and energy value of ethanol– Timing and cost efficiency of biomass to ethanol– Inclusion rates of co-product feeds in livestock diets
• Short term price impact could be significant– Weather induced shortages– Mismatch of acres and ethanol plants
Biomass Ethanol
• Interest in low nitrogen using perennials
• Switchgrass, wood, municipal waste and exotic plants like kanaf, crotalaria, etc.
• Also can use corn stover and coproducts like distillers grains and corn gluten feed
• May reduce demand and acreage of corn
• Technology “5-years away”, but plant announced to operate in 2009
Two Types of Processing
• Wet mills– Very large and costly to construct– Multiple products
• High Fructose Sweetener, corn oil, ethanol• Corn gluten meal, corn gluten feed and others
• Dry mills– Generally smaller and less costly– Two products
• Ethanol• Distillers grains and solubles
Wet Milling-Corn Gluten FeedCORNSTEEP
WASH WATERGRIND
SEPARATION
WET CORN GLUTEN FEED
STARCH, SWEETNER, ALCOHOLGLUTEN MEALCORN OIL
STEEP CORN BRAN
DRY CORN GLUTEN FEED
SEM, screenings, dist solubles
Products of Wet Corn Milling
• One bushel of corn yields
Product Pounds– Starch 31.5
Further processed into 33# of sweetener
or 2.5 gallons of ethanol.
– Gluten feed 13.5– Gluten meal 2.5– Corn meal 1.6
Corn Gluten Feed (CGF)
• Corn bran + steep
• Can be wet or dry
• Moderate crude protein, CP = 16-23%– 80% of CP is DIP (ruminally degradable)
• Low fat, moderate fiber, TDN = 80
• 101-115% of energy value of dry-rolled corn
• Product variation is significant within and across plants due to amount of steep added back to the corn bran
• Looks like oatmeal
Dry Milling-Distillers Grains + Solubles
CORN
GRIND, WET, COOK
FERMENTATION
YEAST, ENZYMES
STILL ALCOHOL & CO2
STILLAGE
DISTILLERS GRAINSWDG, DDG
DISTILLERS SOLUBLESWDGSDDGS
Products of Dry Corn Milling
• One bushel of corn yields
– Ethanol 2.7 gallons– Distillers grains & solubles 17-18 pounds
• DGS are one third the weight of the corn and all but the starch is concentrated into this one-third
• Sulfur is concentrated and may have been used in the fermenting process
• Mycotoxins, if they existed in the corn are also concentrated 3:1
Distillers Grains + Solubles (DGS)
• About 65% Distillers Grains & 35% Solubles (DM basis)
• May be wet or dried
• Higher crude protein, CP = 30%– 65% UIP (undegraded, “bypass”, protein)
• High fat (11%), low fiber, TDN = 70-110
• Concentrates nutrients 3-fold from corn– 0.8% P, 0.35-1.0% Sulfur (variable)
• WDGS looks like mashed potatoes
New “Combination” Products
• Modified wet DGS are available – (35-65% DM)
• Hybrid wet & dry plant combining corn bran and distillers solubles bran cake– Example: Dakota Bran Cake
Nutrient Composition of Selected Corn Milling Co-Products
Factors to Consider Before Feeding Coproducts
• Nutrients only have value if needed– High protein or energy may not be needed
• Abrupt changes may put animals off feed
• Darker brown color indicates it may have been overheated, ties up lysine
• Upper limits on inclusion rates for some livestock types and weights
• Excess sulfur possible at high levels and high water levels of sulfur
• Phosphorous concentration in manure
Factors to Consider Before Feeding Coproducts
• Storage issues, dry product– Additional storage bin– Problems with flow ability in bulk bins
• Storage issues, wet product– Wet product will spoil in 7-14 days depending
on temperature and storage method– Wet product can freeze– Requires good bunk management
Challenges• DGS is most available in late summer
– Seasonally cheapest then too
– Seasonally fewest cattle on feed then too
• Storing wet DGS product
– Material exposed to air spoils in 7-14 days depending on temperature
– Has low pH and does not ensile but will keep in air-tight storage for long periods
– Spoilage loss stored in silage bags (Walker et al)• 20% loss opened and fed day 78-112 post-sealing• 28% loss opened and fed day 190-257 post sealing
When WDGS Price Is Lowest
Seasonal Index of Dried Distillers Grains, Nebraska, 2003-2005
40.00
60.00
80.00
100.00
120.00
140.00
160.00
Month
Pri
ce
In
de
x (
% o
f A
nn
ua
l A
ve
rag
e) Seasonal Price Index
Seasonal Price Index + 1 Std Dev
Seasonal Price Index - 1 Std Dev
Source: AMS & University of Nebraska-Lincoln
Storing WDGS
• Storing wet DGS product
– Often delivered in truck load lots
– Can store wet DGS in bunker, silage bag or in pile covered with plastic to protect from air
– Should mix with tub-ground forage and stored in bunker or bag
– Have to have the “mix” right…
Minimum Levels of Roughage To Mix in WDGS For Storage
Bagginga
Bunker
Grass hay 15% 30-40Wheat straw 12.5 25-32Alfalfa hay 22.5 45-55?DDGS 50 ---ADMCGF 60 ---a300 PSI. Source: Erickson & Klopfenstein
Summary
• Increased corn demand and prices
– Implications for crop acres and land prices– Higher feed cost pressures feeder animal price– Biomass may reduce need for corn, but also
reduce coproduct supply
• Often coproducts will reduce ration cost
• Limits on maximum inclusion rates in diets
• Technical issues with storages and handling
Resources
• http://beef.unl.edu
• www.iowabeefcenter.org
• http://www.ddgs.umn.edu/
