04 grain processing and storage

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04 grain processing and storage Powered By Docstoc
					Grain Processing Methods and
Storage Systems


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
   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
   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
Floury endosperm. More
“open” in structure yet             Crown
opaquein appearance.
Dent corn has about equal            Vitreous endosperm.
proportions of horny to              Also called horneous,
floury starch (compared              corneous or hard endosperm.
to popcorn w/ mostly                 Produces grits in dry
horneous starch.                     milling. Tightly compacted
                                     and translucent. More of
                                     this starch in mature, high
 Pericarp(bran)                      test weight kernels.

Germ scutellum and
embryonic axis.                    Hilum or abscission layer.
Germ will be bigger                Also called blacklayer.
in HOC at the expense              Caused by collapse and
of starch. For each 1%             compression of several layers
increase in oil, expect            of cells at physiological
1.3% decrease in starch.           maturity. Cool weather can
                                   cause premature BL.
Typical Corn vs Optimum High Oil Corn

                Corn                    OPTIMUM

                         Rich in Oil

             •Advantages of HOC
               •More Energy
               •Easier Processing
   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
Grain Processing
   Grains often processed prior to inclusion
    in feeds
       Alters feeding characteristics in predictable
        Altering the Physical
        Form of Grains

1) Dry:
    -   Whole        slow    1) Decrease particle size
    -   Ground
    -   Pelleted             2) Increase intake
    -   Rolled
                             3) Increase digestibility
    -   Steam flaked
    -   Meal          fast
                             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
    amounts of
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
   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
            Methods: Dry Processing
   Dry rolling – pass
    between two rollers
    turning in opposite
    directions– get a
    crack or a coarse
       Can adjust
        closeness of the
        rollers for some
        adjustment of
        fineness of grind
       Corrugated rollers
        used to crush hull
        to increase starch
    Other Methods:
    Dry Processing
   Micronize – microwave to 300o F (especially
    done with milo)

   Roasting – 300o F – puffed grain

   Extruded – heat + pressure = ribbons or

   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

            softens kernel

            process without excess fines
Wet Processing
   Reconstitution
       Harvest grain at low moisture (12-15%
       Add water to dry grain to bring moisture
        content to 30%
       Grain is stored for 21 days in air-tight
            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
   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 Efficiency
Whole Corn             100
High moisture corn     105
Steam flaked corn      103
Dry rolled wheat         95
Steam 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%


** Note: grains will need to be drier if insects are a problem; also can

       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
         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
         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
       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
            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
       Must be fed to livestock
       Must be stored air tight
       Handle more weight because of

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