Importance of Forages In Animal Diets

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Module 3 Forage Value/Production
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IMPORTANCE OF FORAGES IN ANIMAL DIETS

• Source of Nutrients
• -Protein
• Prebud gt Mature
• Legume gt Grasses
• Quality (amino acid profile) can be hi
• -Energy
• Cell contents (nonfiberous CHO)
• available to non-ruminants/ruminants
• Cell wall
• Cellulose, Hemicellulose
• available to ruminant
• source of physical/effective fiber
• -Minerals
• Legumes gt grasses
• Good sources of Ca, P, K
• -Vitamins
• Pasture good source
• Inactivated with storage and fermentation
• -Fat little present

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IMPORTANCE OF FORAGES IN ANIMAL DIETS

• Source of Physical Fiber
• - Gut mobility/environment
• Rumen
• Lower GIT
• - Reguritation
• - Saliva Production

Economics Lower Cost
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EXPRESSING FIBER REQUIREMENTS - RUMINANTS

• Diet contain at least 17 ADF
• Forage to concentrate ratio
• dairy cow 4060, DM basis
• Forage intake as a of BW
• 1 to 1.5 of BW
• Forage particle length
• Set harvestor cut at 1/4 to 3/8 results in
• 15 gt 1 1/2 length
• 25 3/4 to 1 1/2 length
• 60 1/8 to 3/4

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FORAGES

• Grasses
• Require N fertilization
• Examples
• Brome
• Orchard
• Timothy
• Tall Fescue
• Bermuda
• Corn

• Legumes
• Fix N
• Examples
• Alfalfa
• Clover
• Red
• White
• Alsike
• Soybean

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SEEDLING DEVELOPMENT
Legume
Grass
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FORAGE YIELDS AND DIGESTIBILITY
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ALFALFA PLANT - GROWTH/MATURITION
Leaf
Stem

Protein
Stage of Maturity
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STRATEGY FOR FORAGE QUALITY

• Harvest in prebud stage
• If many acres need to be harvested
• Contract it out
• Start early so range encompasses prebud to
  midbloom
• Use combinations of methods to harvest haylage,
  balage, grazing
• If grazing, rotate pastures. Vary pastures with
  early, late season grass varieties.
• Plant corn varieties varying in maturity date
  (75 120 day)

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TOP DAIRY FORAGES
Alfalfa Haylage or dry hay Hi feed value
protein, Ca 4 - 5 cuttings/season Hi yield
DM/acre Drought tolerant Needs well drained
soil pH 6.5 - 7.0 for max prod Corn
Silage Max yield of feed energy Source of
fiber
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BEEF FORAGES

• Pastures/Hay fields - River Bend Farm
• Combination of grasses
• Smooth brome grass
• Orchard grass
• Tall fescue
• plus white clover
• Provides
• Continuous/close grazing
• Trample resistant
• Some species drought tolerant
• Meets nutrient requirements

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VAN SOEST DETERGENT SYSTEM
Ground forage material
Digest with neutral detergent (ND)
ND solubles Cell contents
ND insoluble fiber Cell wall components
Digest with acid detergent (AD)
AD solubles Hemicellulose Cell wall N
Acid insoluble fiber
Digest with 72 H2SO4
Acid insoluble lignin
Solubles Cellulose
Adopted early 1970s
Lignin by loss on ignition
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FEED CARBOHYDRATE FRACTIONS
Cellulose
Hemicellulose
Pectin
Fructans
Starch
RUMEN FERMENTATION
Uronic acids
Pentoses
Galactose
Dextrans
Cellobiose
Sucrose
Pentose pathway
Fructose
Maltose
Glucose
ATP
Pyruvate
Lactate
Formate CO2 H2
Oxalacetate
Malate
Acetyl-CoA
Fumarate
2H
ATP
Aceto- acetyl-CoA
Succinate
ATP
Succinyl - CoA
Acetaldehyde
Methylmalonyl-CoA
Acrylate
ATP
2 ATP
Propionyl-CoA
Ethanol
CH4
ATP
Acetate
Butyrate
Propionate
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FORAGE FIBER AND QUALITY RELATIONSHIP

• Acid Detergent Fiber (ADF)
• Highly related to the digestibility of a forage.
• Neutral Detergent Fiber (NDF)
• Highly correlated with dry matter intake of the
  forage.
• Digestible Dry Matter (DDM)
• DDM 88.9 (0.779 x ADF )
• Dry Matter Intake (DMI)
• DMI ( of body weight) (120) / (Forage NDF (
  of DM))
• Relative Feed Value (RFV)
• RFV (DDM x DMI) / (1.29)

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CORN PLANT - GROWTH/MATURITION

Fully dented
Grain
Late dough/early dent
Kernel
Blister
Growth
Cobs Silk
Stalk Tassel
Leaves

120
110
80
60
40
20
Maturity/Days
Plant
0
10
35
100
Dry Matter

Late Dough/early dent 35 DM
Harvest for silage
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SILAGE FERMENTATION
PHASE 1. Cell respiration production of
CO2 production of heat
PHASE 4. lactic acid formation
PHASE 5. depends upon phase 4 if enough
lactic acid was formed, the silage
remains constant If insufficient acid was
formed, butyirc acid production begins Protein
may be broken down and spoilage may be excessive
PHASE 2. Production of acetic acid
PHASE 3. lactic acid formation begins
69F
90F
84F
Temperature Change
pH Change
4.0
6.0
4.2
3.8
ACETIC ACID BACTERIA
LACTIC ACID BACTERIA
RATE OF SEEPAGE LOSS
1
2
3
20
7
12
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AGE OF SILAGE (days)
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SILAGE FERMENTATION
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SILAGE PRODUCTION
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HARVEST DRY MATTER (DM) AFFECTS SILAGE QUALITY
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PUTTING UP SILAGE
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NITRATE/NITRITE POISONING

• The Problem
• Nitrate can accumulate in plants/stalk
• Nitrate is converted to nitrite in rumen
• Nitrite to blood resulting in methanoglopinemia
  (brown blood, inability to transport oxygen)
• Solutions
• Test crop for nitrate content
• 0 - .44 safe to feed
• .45 - .75 feed with caution
• introduce to ration gradually
• increase concentrate ratio to dilute
• restrict single meal size
• gt 1.00 Dont feed
• Harvesting methodology in a drought
• Dont harvest 3 5 days after a heavy rain
• Harvest crop at maturity
• Harvest hi, leaving stalk, hi nitrate
  concentration in field
• Harvest for silage rather than direct feed