Forage Quality and Supplies

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Forage Quality and Supplies

• AVS466
• Dairy Cattle Nutrition
• David Marcinkowski

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Grass Silage Variation
Northeast DHIA Data 2004-2005
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Factors Affecting Forage Quality

• Soil type and fertility
• Variety of plant
• Plant species mix
• Weeds and weed type
• Age of stand
• Winterkill
• Weather, including
• temperature
• humidity
• season (day length)
• season (type -- cold, late)
• moisture (rain)
• length of time between cutting and rain

• Plant maturity
• Insect damage
• Disease
• Mower height
• Haying equipment -- bale package, bale
  ventilation
• Time between cutting and harvest
• Plant moisture at harvest
• Time of day hay is cut
• Drying agents Preservatives
• Artificial drying
• Storage methods

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Maturation of Plant Cell Wall
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Alfalfa DM Yield with Stages of Maturity
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Growing Season Affects on Alfalfa
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Hay Quality Requirements of Different Dairy
Animals
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Effect of Different Alfalfa Cutting Frequencies
on Yield, Quality, Weeds, and Stand Life.
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Effect of Alfalfa Maturity on Milk Production
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Orchardgrass Digestibility
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Mixed Hay Quality by Stage of Maturity
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Effect of stage of maturity of green chopped
alfalfa-brome forage on digestibility, forage
intake, and milk production
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Relative Feed Value (RFV)

• Relative feed value is a way of comparing hay and
  haylage based on quality
• RFV 100 is an average quality forage
• Calculate RFV from the Digestible Dry Matter
  (DDM) and the Estimated Dry matter intake (DMI)
• Formulas
• DDM 88.9 - (0.779 ADF)
• DMI 120 / NDF
• RFV (DDM DMI) / 1.29

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Quality Standards for Hay
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Rain Losses on Alfalfa Hay
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Effect of Mold on Hay Fed to Beef Cattle
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Sensory Evaluation of Hay/Silage

• Color
• Plant maturity
• Hay tops
• Kernal maturity
• Coarseness of stalks
• Length of cut
• Haylage - 3/8 to 5/8" in TLC Corn Silage - 3/8 to
  1/2" evidence of wrecked kernals
• Longer fibers gt3/4"
• Silo shows evidence of packing
• Spoilage/mold
• Smell

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Evaluating Forages
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Visual Evaluation
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Forage Analysis

• Dry matter - Scale and Microwave or cooker
  Recommended DM
• Hay - 1 0-20
• Silage - 30 - 50
• pH of silage
• Corn under 4.0
• Haylage under 4.5
• Best way is to send sample to lab

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Lab Analysis

• Wet Chemistry
• NIRS
• Near Infrared Reflectance Spectroscopy

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Wet Chemistry

• Tried and true method
• Slower
• Use numerous chemicals- problems with disposal
• Not portable
• Subject to technician error
• Much better at analyzing minerals

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NIRS

• New Invented in 1970's
• Scanning spectrophotometer
• All organic substances have NIR absorption bands
• Protein, fiber, starch minerals all differ
• Calibrating the NIRS
• Broad range of feed qualities
• Perform wet chemistry
• Regression equations are used as predictors
• Must continually update equations

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NIRS

• Fast
• No chemicals used
• Portable unit that can travel anywhere
• Equipment is costly
• Only as good as the prediction equation used
• Poor at analyzing minerals
• Can only measure components that are more than 1
  of the DM
• Can measure smaller things if there is a good
  correlation with things you can measure.

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Wet Chemistry vs NIRS

• Wet Chemistry
• Tried and true method
• Slower and expensive
• Uses chemicals - problems with disposal
• Not portable
• Subject to technician error
• Much better at analyzing minerals

• NIRS
• Fast and cheap
• No chemicals used
• Portable unit
• More repeatable results
• Only as good as the prediction equation used
• Measure components that are more than 1 of the
  DM
• Can go lower if correlation with something else
• Not as good at analyzing minerals

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Sampling Feeds

• Spend time getting a good representative sample
• Not easy to do
• Important since the analysis of the sample will
  dictate your ration composition for a significant
  period of time
• Need to know the structure of the bale/pile/silo
  to sample.
• Be conscious that light and air exposure
  significantly affects the sample.
• 20 Samples

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Hay Sampling
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Silage Sampling

• More homogenous than hay but still problems
• Face exposed to elements
• Upright silos difficult to sample - all you can
  do is take them off the top
• Bunker silos
• Dig into the face because air exposure causes
  deterioration 
• Take minimum of 20 grab samples from the face at
  various heights
• Another option take a sample from the mixer wagon
  

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Commodity Sampling

• Can be very variable in composition
• Quality control important
• Feed mills buy based on analysis
• Use a grain probe to sample the center of the
  pile
• Collect from a flowing stream

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Grain Sampling
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Feed Samples

• Know what sample size is required
• Be careful splitting samples
• Ship appropriately
• Silage exclude air
• Frozen?

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Understanding Feed Analyses
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Optimum DM Content for Good Silage-making
balage
Hay
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Protein Measures

• Crude Protein (CP)
• Total protein in the sample including true
  protein and non-protein nitrogen
• Soluble Protein (SP or SIP)
• Proteins and NPN that are rapidly broken down in
  the rumen
• Used to synthesize microbial protein
• Degradable Protein (RDP or DIP)
• Soluble protein and proteins of intermediate
  ruminal degradability
• Used to synthesize microbial protein

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Protein Measures continued

• Undegradable Protein (RUP or UIP)
• Proteins with degradability and escape rumen
  digestion
• Also called escape or bypass protein
• Acid Detergent Insoluble Crude Protein (ADICP)
• Also known as heat damaged or unavailable protein
• Caused by heating during fermentation or drying
• Protein bound to carbohydrates making them
  indigestible
• Neutral Detergent Insoluble Crude Protein (NDICP)
• Represents the portion of the undegradable
  protein that is available to the animal.

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Energy Measures

• Acid Detergent Fiber (ADF)
• Cellulose and lignin.
• Negatively correlated with overall digestibility.
  
• Neutral Detergent Fiber (NDF)
• Hemicellulose, cellulose and lignin
• The cell wall or structural carbohydrates
• Negatively correlated with intake.
• Non Fiber Carbohydrates (NFC)
• Non-cell wall carbohydrates
• Starch, sugar, pectin and fermentation acids
• Broken down by microbes in the rumen
• Calculated as 100 - (CP (NDF - NDICP)
  Fat Ash).

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Energy Measures continued

• Nonstructural Carbohydrates (NSC)
• Starch sugar
• Determined enzmatically
• Net Energy of Lactation (NEL)
• Estimate of the energy value of a feed used for
  maintenance plus milk production
• MCALs

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Other Measures

• In Vitro True Digestibility (IVTD)
• Simulates rumen digestion in lab
• Samples incubated in rumen fluid
• Measure of digestibility used to estimate energy.
  
• Neutral Detergent Fiber Digestibility (NDFD)
• All NDF not created equal
• NDF digested during in vitro incubation
• Used to rank forages on fiber digestibility and
  in energy calculations.
• Relative Feed Value (RFV)
• Index for ranking forages based on digestibility
  and intake
• Calculated from ADF and NDF
• RFV of 100 is an average score
• Relative Feed Quality (RFQ)
• Similar to RFV
• More comprehensive uses CP, ADF, NDF, fat, ash
  and NDFC (48hr)
• Average score of 100. Higher RFQbetter the
  quality.

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Expected amounts of common fermentation end
products in silages
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Forage Inventories - How much is there?
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Forage Requirements
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Forage Inventory

• Bales
• Easy
• Estimate/count the number of bales  times the
  weight per bale lbs of hay
• Convert to tons
• Silos
• Tower silos
• Bottom is packed really tight - Use a table
• Bunkers silos
• Each cubic foot holds 10-12 lb. of haylage DM
• Or 14-16 lb of corn silage DM
• You must divide by the forage DM to get the total
  lbs of silage on an as fed basis

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Calculating Cubic Feet
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