Harvesting Quality Corn Silage by Neil Broadwater Regional Extension Educator Dairy

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Harvesting Quality Corn SilagebyNeil
BroadwaterRegional Extension Educator - Dairy

• Goals
• Maintaining forage quality from field to dairy
  animal
• Minimum shrinkage and spoilage
• Excellent dairy animal performance

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The Feed Pyramid
Dairy rations begin with high quality forages.
Pyramid by Rick Lundquist, 1995
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• Corn Silage If a producer harvests 25 acres of
  corn silage and the yield is 24 ton/acre (as is),
  then there should be 600 tons (as is) of corn
  silage for the next 12 months.
• Are this statement true?
• No
• There is feed loss through fermentation, wastage,
  spoilage that will affect the corn silage
  inventory.

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How much loss is acceptable?

• Yet, on some farms, we can get up to 25 loss
  less in tower silos -- equivalent to 5 ton corn
  silage yield loss in the field (as is basis).
• It is easy to lose this much silage if everything
  isnt done to prevent wastage and spoilage.
• The cost of producing the silage that doesnt get
  to the bunk also needs to be taken into
  consideration.

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Moisture Content for Corn Silage

• Whole plant moisture, rather than kernel
  milkline, should determine when to start chopping
• Therefore, start checking for moisture when
  kernels are dented and milkline is visible

Koster Moisture Tester
Bunkers around 33 DM Piles around 33
DM Stave Silos about 36 DM Bags 30-40 DM
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Proper Particle Size Is Important

• Fiber length affects forage quality, compaction
  for proper fermentation and roughage value for
  proper rumen function.
• Silages too coarse cause a separation problem in
  the bunk (wasted feed).
• Incorrect fiber length can lead to cows going off
  feed, low fat test, decline in milk production,
  displaced abomasums, laminitis, and liver
  abscesses.
• Effective fiber -- needed to form a fiber mat
  that is responsible for the stimulation of cud
  chewing, salivation and rumen motility.

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Length of Cut

• Corn Silage --
• Theoretical cut at ¼ inch

• Processed Corn Silage --
• ½ - ¾ TLC promotes cud chewing and proper rumen
  function. Roller spacing thickness of a dime
  (
• A 3/8 TLC may reduce the formation of a fiber
  mat in the rumen, resulting in less effective
  fiber. This increases risk of fresh cow
  disorders.

• These guidelines
• Provide adequate animal rumen function, and
• Are appropriate enough to pack well for proper
  fermentation.
• Frequently observe the forages and make
  adjustments in harvest cut length to obtain
  desired particle sizes.

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Particle Size Affects Rumination

• If too fine
• chewing ?, saliva ?, buffering capacity ?, pH ?
• If adequate
• chewing ?, saliva ?, buffering capacity ?, pH ?

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Forage Fiber Length Study2000

• Corn Silage Results 33 Farms
• (Figures are expressed as percentages)
• ---average for each visit---
  ----all visits----
• Screen Visit 1 Visit 2
  Visit 3 Range Average Guideline
• Top 8.4 6.2 6.2 1-75
  6.9
• Middle 64.6 65.9 65.1 5-83
  65.2 50-60
• Bottom 26.1 26.7 26.4 7-62
  26.4
• u unprocessed p processed
• Samples taken from -- 21 bunkers 6 bags 8
  uprights 1 pile

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Managing Particle Size Distribution

• If particle size is being reduced by the silo
  unloader, augers or TMR mixing equipment, a
  somewhat longer theoretical cut may be needed.
• Analyzing particle size often from the TMR
  helps to make the ration calculated by the
  nutritionist more reliable and successful for the
  dairy herd.
• Check for uneven particle distribution
• Take four samples from bunk. Have each analyzed.
  Particle variation should be

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Kernel Processing

• Advantages
• May be more digestible in the rumen
• Tears or shears the corn stalk
• Reduces the size of the corn cob and alleviates
  sorting
• Breaks corn kernel allowing more starch to be
  available to the animal
• Better starch digestibility could increase milk
  production slightly

• Is it beneficial?
• For corn silage that would have mature or hard
  kernels
• If there is enough acres of corn silage to spread
  out the processing cost
• Probably unnecessary if corn silage harvested at
  ideal moisture and ¼ TLC

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Cutting Height

• A balance of getting maximum yield vs. higher
  quality corn silage
• Raising cut height to 18 reduces DM yield about
  15
• Milk/ton increases because more fibrous and less
  digestible portion is left in field
• Milk/acre reduced about 3
• Varies yearly depending on yield and crop quality
• More erosion control from more residue in field?
• Increased quality probably doesnt offset yield
  loss

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Nutritive Value of Corn SilageMILK2000

• An index method developed at U of WI
• Results based on DM yield and energy content
• Energy calculation based on CP, NDF, starch,
  non-starch and fat content
• Good way to compare hybrids
• Limitations
• Energy calculation is only as good as inputs that
  go into the equation.
• Methods for measuring NDF and starch
  digestibility

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Types of Hybrids

• Brown midrid
• studies in 1999, 2000, 2001
• Cows ate 3.4 more DM, 3.5 more milk per day
  than other hybrids.
• Digestibility is greater at equal DM intakes that
  other hybrids
• However, the increased milk is from an increased
  DM intake and not an increased energy content of
  the corn silage.
• Therefore, with more seed cost, decreased yield,
  its use is questionable.
• May be more effective when to cows whose
  production is limited by rumen fill.
• May need to decrease corn in the diet.

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Types of Hybrids

• Leafy corn silages
• 6 studies in 1999, 2000, 2001, 2002, 2003
• Cows consumed 0.3 less DM, produced 0.5 more
  milk/day vs other silages.
• No overall nutrient composition difference
• Thus, any advantage is probably in DM yield or
  agronomic trait rather than cow performance.

• High Oil Corn silages
• 3 studies in 1999, 2000, 2001
• Cows ate 3.1 more DM, produced 3 more
  milk/day vs. other typical silages
• Higher fat content (1-3) increased energy
  content, but energetic efficiency for milk
  production was not increased as cows ate 3 more
  DM to produce 3 more milk

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Forage Storage (and Feeding) System?

• There is no one best type for all farm
  situations.
• There is no method of storage that can improve
  harvesting poor quality silage.
• With proper management, there is little
  difference in silage quality from the various
  types.
• Storing forages on top of one another or in front
  of one another does not allow for the optimal
  utilization of forages.
• An optimal forage system allows for the
  segmenting of forages by quality for various
  animal groups.

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Forage Storage Management

• The key is to get anaerobic fermentation as soon
  as possible and to reach a pH below 5.0 as
  rapidly as possible.
• The factors that influence this goal -- similar
  for all storage systems.
• Fill as rapidly as possible. This minimizes the
  exposure time to Oxygen.
• Keep knives sharp and cut forage at correct
  length.
• Ensile at correct moisture.
• Spoiled silage affects DMI, digestibility of
  feed, affects the forage mat in the rumen, and
  reduces nutritive value.

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Density

• DM Loss as influenced by Silage Density
• (lbs. DM/cu. Ft DM loss, 180 days ()
• 10 20.2
• 14 16.8
• 15 15.9
• 16 15.1
• 18 13.4
• 22 10.0

• High density increases storage capacity, reduces
  silage porosity, which reduces oxidation loss and
  preserves the high quality feed harvested.
• Silage density depends on plant species, crop
  maturity, moisture content, length of cut, silo
  filling method, distribution, compaction.

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Silage Piles

• From filling through Feedout, DM losses can be 21 with Good Management
• DM losses can be 50 without proper management
• Cover ASAP
• 6 mil plastic
• Tires touching each other
• Seal edges

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Silage Bales

• At least 6 mil of plastic wrap cover, preferably
  8 mil.
• Total plastic thickness, not the number of wraps
  is the most important factor to resist oxygen
  from reaching the feed.
• Stacking silage bales takes up less space and
  help protect themselves from the elements,
  rodents, birds, etc. Be careful not to rip
  plastic when stacking.
• Spoilage due to hole limited only to that one
  bale.
• Should be wrapped within 24 hrs.
• Takes 3 minutes to wrap.

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Bunkers

• Dimensions
• length width 2x width of packing
  tractor
• Density Goal greater than 16 lbs DM/cu.ft.
• Research on 168 bunker silos U of WI/USDA
  Forage Research Center, 1999 (Holmes and Muck)
• 87 bunker silos with haylage
• DM average 42 range 24-67
• Dry Density average 14.8 range
  6.6-27.1 lbs/cu.ft.
• 81 bunker silos with corn silage
• DM average 34 range 25-46
• Dry Density average 14.5 range
  7.8-23.6 lbs/cu ft

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Bunkers

• Spread in
• Continue packing for ½ hour after the last load
  for the day.
• Start packing again the next filling day about ½
  hour before the first load is added.
• U of WI formula divide the pack tractor weight
  by 800 to get tons of silage that can be packed
  per hour.
• Ex A 40,000 lb tractor can pack about 50
  tons/hr.

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Bags

• Results from 3 U of WI Research farms, 2001 (Muck
  and Holmes)
• 20 bags of haylage 19 bags of corn silage
  analyzed
• As particle size increased, density decreases
• DM losses ranged from 0-40, average 14.6
  (Haylage - 15, CS -14)
• Density averages ranged from 10-18 lbs.DM/cu.ft.
• Density within bags was highly variable. 
  Densities at top and sides were approximately 40
  of those at a bag's bottom center.

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Bags

• Most spoilage in 40 DM, porous silages.
• Higher total losses from emptying in warm
  weather. Save the best bags for summer feeding.
• Losses managed.
• U of WI Research, 2001

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Minimizing Silage Losses

• When silo filling is complete, cover the silo
  ASAP.
• Plastic covers should be protected from punctures
  by rodents, livestock, dogs, cats, and small wild
  animals.
• Weekly inspecting for and repairing holes in the
  plastic cover to exclude air and water.
• Mowing around the silo and bags tends to
  discourage rodents.
• Cover bunker if filling is going to be
  interrupted for more than two days.

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• Dont Feed Spoiled Silage --
• Do not feed spoiled silage to stretch haylage
  inventory.
• Poor quality haylage will give the producer a
  poor quality ration.
• Feeding spoiled silage, even at 5 of the total
  DM, reduces intake.
• Nutrient digestibility and rumen health will be
  compromised.
• Feeding spoiled silage to heifers and dry cows
  has a negative affect on fertility and
  reproductive performance.

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• Two University of Minnesota web sites
• http//www.extension.umn.edu/dairy
• http//forages.coafes.umn.edu/

Thank you