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Wheat
oat sorghum
The complete hull consists of a lemma, a palea, an awn (tail), a rachilla (grain stem) and two sterile lemmas. Once grinded with light force, the husk easily breaks itself apart from the inner caryopsis. It is inedible but makes up approximately 20-25% of the total grain weight depending on the variety.
The caryopsis (brown rice) consists of three fibrous bran tissues- pericarp (or fruit coat), tegmen (seed coat) and aleurone- and endosperm (hard dough) and embryo.
Pericarp consists of three fibrous layers of protein, cellulose and hemicellulose.
Tegmen is next and inner to the pericarp. It consists of two-piled tissues with arrays of fatty material.
Aleurone is next and inner to the tegmen. It envelops the starchy endosperm and the embryo. Aleurone tissue contains high protein and partially oil, cellulose and hemicellulose.
Endosperm, the largest porting of the rice grain, is developed from pollination of nucleus of the pollen grain and polar nuclei of the pistil. Its starchy content comprises of mostly complex carbohydrates and some proteins.
Embryo, the reproductive organ of the grain, is one of the two products of the “double fertilization process”- one where nucleus of the pollen grain reaches one of the egg cells in the pistil. Embryo is rich in protein and fat.
Structure of the Grain Kernel (Seed) Endosperm – contains most of the
starch
Germ – embryo or the sprouting portion of the seed
High in oil and protein – not good flour but it is good animal feed
Bran – seed coat and other layers
Vitreous endosperm.Also called horneous,corneous or hard endosperm.Produces grits in drymilling. Tightly compactedand translucent. More ofthis starch in mature, hightest weight kernels.
Dent
Crown
Pericarp(bran)
Hilum or abscission layer.Also called blacklayer.Caused by collapse andcompression of several layersof cells at physiologicalmaturity. Cool weather cancause premature BL.
Germ scutellum andembryonic axis.Germ will be biggerin HOC at the expenseof starch. For each 1%increase in oil, expect1.3% decrease in starch.
Floury endosperm. More“open” in structure yetopaquein appearance.Dent corn has about equalproportions of horny tofloury starch (comparedto popcorn w/ mostlyhorneous starch.
Typical Corn OPTIMUM
HOC
Endosperm:
StarchEmbryo:
Rich in Oil
Typical Corn vs Optimum® High Oil Corn
•Advantages of HOC•More Energy•Easier Processing
Endosperm Cells fill with starch granules
Starch granules are enveloped in a protein matrix which impedes digestion of starch
If we process grain to break open the granule, can increase the digestion of starch
Grains differ in rumen fermentability largely due to the nature of the endosperm and protein matrix surrounding the granules
Less difference in intestinal digestibility
Grains for Ruminants Small cereal grains have very fermentable
starch and may actually be dangerous
Corn is lower in fermentability and is usually processed to increase starch fermentability
Grain sorghum or milo is lowest; must be processed
Grain Processing Grains often processed prior to
inclusion in feeds Alters feeding characteristics in
predictable ways
Altering the Physical Form of Grains
1) Dry:- Whole slow- Ground- Pelleted- Rolled - Steam flaked- Meal fast
1) Decrease particle size
2) Increase intake
3) Increase digestibility
4) Increase starch availability
Grain Processing Physical – interrupt the seed coat
Expose grain to digestive enzymes Make more palatable
Heating – starch swells and gelatinization occurs Granules burst Gelatinized starch is more digestible
***advantage of physical processing is with small, hard grains and/or thick seed coat grains
*** advantage of heating is with less fermentable grains; corn and milo
Methods: Dry Processing
Grinding – hammer mill and screens – anywhere from coarse to fine particle size
Creates considerable amounts of fines
Problems with Fine Ground Feeds Dusty feed Wind loss Stomach ulcers (erosion of GT wall) in swine Acidosis in ruminants
*** Therefore want a medium grind for swine and coarse grind for cattle
*** Processing is expensive; it is usually more cost-effective when grains are expensive
MECHANISM AND SYMPTOMS of Acidosis
Cattle and sheep have a large fore-stomach, the rumen, which contains a stable population of microorganisms. These microorganisms derive energy mainly by fermenting the carbohydrates which the host animal ingests.
The events leading to acidosis occur when the animal’s diet is suddenly changed from forage to concentrate (high in starch or other rapidly fermentable carbohydrates), or when it is fed excessive amounts of such concentrates.
Furthermore glucose, normally found in extremely low concentrations in the rumen, is liberated from starch or other rapidly fermented carbohydrates, resulting in increased ruminal glucose concentrations. This has negative consequences including growth of organisms such as Streptococcus bovis and other lactic acid producing organisms, and increased ruminal osmolality, which further increases ruminal acidity by inhibiting VFA absorption from the rumen. As the rate of VFA production exceeds their rate of removal, rumen pH may fall below 6.0.
Acidosis is categorized as acute or subacute primarily on the basis of presence or absence of various symptoms. Symptoms of acute acidosis include anorexia, rumen stasis, rumenitis, diarrhea, dehydration, laminitis and liver abscesses. Rumen lactic acid levels will also be high with a concomitant drop in pH. The above-mentioned changes in rumen microbial population, as well as a reduction or complete absence of ciliated protozoa will also be evident.
Methods: Dry Processing Dry rolling – pass
between two rollers turning in opposite directions– get a crack or a coarse grind
Can adjust closeness of the rollers for some adjustment of fineness of grind
Corrugated rollers used to crush hull to increase starch digestibility
Other Methods: Dry Processing
Micronize – microwave to 300o F (especially done with milo)
Roasting – 300o F – puffed grain
Extruded – heat + pressure = ribbons or flakes
Pellet (or cube) – grind, mix with binder and pass through dies of various sizes Can combine various feedstuffs
Methods: Wet Processing
Tempering
Add water and allow to soak for 18 to 24 hours before feeding – some swelling of starch
Sometimes add a tempering agent; aids in the uptake of water
Probably most benefit with small, hard kernels (barley and wheat)
softens kernel
process without excess fines
Wet Processing Reconstitution
Harvest grain at low moisture (12-15% moisture)
Add water to dry grain to bring moisture content to 30%
Grain is stored for 21 days in air-tight environment
Rolled or ground prior to feeding Usually does not equal high moisture grain Used most commonly with milo due to protein
matrix surrounding starch molecules
Methods: Wet Processing
Steam rolled Steam for 1 to 8 minutes – get very little
gelatinization – not much different than dry rolled
Steam flaked Steam for 15 to 30 minutes, then roll into
a flake Probably the most extreme treatment and
most improvement in digestion Final product 18-20% moisture Low bushel weight (24-26 lbs)
Relative Feeding Values
Feed EfficiencyWhole Corn 100High moisture corn 105Steam flaked corn 103Dry rolled wheat 95Steam flaked wheat 101
Grain Storage Moisture is the major factor involved in grain
storage Need to have dry feeds for bin or shed storage
Small grains – whole: 12% moisture Corn – whole: 14% moisture Ground grains (or with >12% broken kernels): 11%
moisture
** Note: grains will need to be drier if insects are a problem; also can fumigate
These values depend on humidity, temperature and air flow
Grain Storage Higher moisture levels cause:
Heating Caking Mold:
• Produce mycotoxins, cause reduced performance, poor feed efficiency, diarrhea, liver disease, infertility, abortion, poor immune functions
• These effects can be a problem for humans, some are carcinogenic
Grain Storage Important molds found in grains
Ergot, clavicep purpurea• Very potent toxin that accumulates in the animal,
especially in cereal grains (triticale), zero tolerance
Aspergillus flavis, produce aflatoxin (a mycotoxin)
• Extremely common mold, often causes deleterious effects in livestock including liver disease
Fusarium fungus: produces zearalanone and vomitoxin (also known as DON)
Grain Storage Steps to prevent molds/mycotoxins
Moisture test, reject any grain which is too wet or that you can’t dry (15% moisture or your known moisture content for your storage)
Obtain a sample and analyze any suspect grains for mycotoxins
Keep equipment clean and mold free – don’t contaminate clean grain!
Grain Storage Amount of mold (except ergot) to tolerate:
< 10% damage is probably safe 10 to 40% damage is risky >40% damage – absolutely not
Do not feed to young, growing animals or to reproducing animals (toxins can kill the embryos)
Grain Storage – Cost Considerations
2% reduction in price for each moisture point over permissible level
Lower level of DM (don’t pay for water) Storage loss or cost of drying
Grain Storage Alternatives (to dry grain)
Longer field drying Solar drying Preservatives
0.5% propionic acid – protects grains up to 24% moisture
Microbial inoculants; seems to be effective Both also extend bunk life
High moisture grain storage
*** Actually, high moisture grains have superior feed value (feed efficiency)
High Moisture Grain 22 to 35% moisture As with silage need airtight structure for
anaerobic fermentation Coarsely grind, pack in air-tight silo for fermentation
Can be stored whole, then rolled upon removal from silo pH dropped to 4 or less, stops bacteria growth and
product preserved increases palatability
Faster fermentation More soluble nutrients Can expel oxygen with lower water content – acids
concentrate faster
High Moisture Grain Advantages
Early harvest – reduce field loss; shattering, lodging, hail, bird, deer
No artificial drying needed Bunker may be lower storage cost Corn: less risk of frost damage ** increased feed efficiency
High Moisture Grain Disadvantage
Grain must be stored immediately – does not allow much buying and selling
Must be fed to livestock Must be stored air tight Handle more weight because of
water
