Transcript Importance of Forages In Animal Diets

Module 3
Forage Value/Production
IMPORTANCE OF FORAGES IN ANIMAL DIETS
Source of Nutrients
-Protein
• Prebud > Mature
• Legume > 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 > grasses
Good sources of Ca, P, K
-Vitamins
Pasture good source
Inactivated with storage and fermentation
-Fat little present
IMPORTANCE OF FORAGES IN ANIMAL DIETS
Source of Physical Fiber
- Gut mobility/environment
• Rumen
• Lower GIT
- Reguritation
- Saliva Production
Economics
Lower Cost
Physical effectiveness factors (PEF) for forages and concentrates
Forage
Long
Coarse
Medium-coarse
Medium
Medium-fine
Fine
Ground
Concentrates
Rolled
Rolled
Coarse
Medium
Fine
a
PEF
Grass
Hay
Silage
1.00
0.95
0.90
0.85
0.80
0.70
0.40
*
*
*
Fine
------*
---*
*
Fine
----------
---*
*
*
---*
*
---------*
*
*
----
------*
*
*
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------------------Byproducts
0.80
0.70
0.60
0.40
0.30
----------------
----------------
----------------
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Hi-Moist. corn
Barley
Cr. corna
Med. Gd cornb
Fine/Gd/Pell
Cracked or coarsely ground corn
Medium ground corn and concentrates
b
Alfafa
Hay
Silage
Corn
silage
Concentrates
EXPRESSING FIBER REQUIREMENTS - RUMINANTS
• Diet contain at least 17% ADF
• Forage to concentrate ratio
dairy cow 40:60, 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% > 1 1/2” length
25%
3/4 to 1 1/2” length
60%
1/8 to 3/4”
FORAGES
Grasses
Legumes
Require N fertilization
Fix N
Examples
Examples
• Brome
• Alfalfa
• Orchard
• Clover
• Timothy
Red
• Tall Fescue
White
• Bermuda
Alsike
• Corn
• Soybean
SEEDLING DEVELOPMENT
Legume
Grass
FORAGE YIELDS AND DIGESTIBILITY
ALFALFA PLANT - GROWTH/MATURITION
70
% Leaf
60
50
%
% Stem
40
30
% Protein
20
10
0
Prebud
10% Bloom
50% Bloom
Stage of Maturity
Full Bloom
EFFECT OF FORAGE MATURITY ON NUTRIENT COMPOSITION
Forage
Stage of
Maturity
Alfalfa
Prebloom
First Flower
Midbloom
Full Bloom
Timothy
Prehead
Head
TDN
(%)
63
56
52
49
CP
(%)
19.4
17.9
16.0
15.0
Nutrient
Lysine
(%)
1.10
0.94
0.90
0.64
50
45
11.5
9.0
-------
Ca
(%)
2.10
1.75
1.50
1.29
P
(%)
0.34
0.28
0.25
0.25
0.50
0.41
0.25
0.19
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)
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
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
VAN SOEST DETERGENT SYSTEM
Ground forage material
Digest with neutral detergent (ND)
ND solubles
ND insoluble fiber
Cell contents
Cell wall components
Digest with acid detergent (AD)
AD solubles
Acid insoluble fiber
Hemicellulose
Cell wall N
Digest with 72% H2SO4
Solubles
Adopted early 1970’s
Acid insoluble lignin
Cellulose
Lignin by loss on ignition
FORAGE ORGANIC MATTER FRACTIONS AND RUMEN AVAILABILITY
Fraction
Components
Availability
Cell contents
Lipids
Sugars, organic acids and
water-soluble matter
Pectin, starch
Non- Protein N
Soluble protein
Almost completely digestible
Not lignified
Hemicellulose
Fiber-bound protein
Partially digestible according to
the degree of lignification
Cell wall constituents
1. Soluble in acid-detergent
2. Acid-detergent fiber
Cellulose
Lignin
Lignified N
BIOAVAILABILITY OF FORAGE COMPONENTS
Component
Class 1b
Soluble carbohydrate
Starch
Organic acids
Protein
Pectin
True
digestibility
100
90+
100
90+
98
Limiting factora
Intake
Passage with fecal loss
Intake and/or toxicity
Fermentation
Fermentation
Class 2b
Cellulose
Hemicellulose
Variable
Variable
Lignification, silicification and
cutinization
Class 3b
Lignin
Cutin
Silica
Tannins, essential oils and polyphenols
Indigestible
Indigestible
Indigestible
NA
Limit use of cell wall
"
"
Inhibitors of proteases and cellulases
a
First limiting factor relative to animal utilization and response.
b
Classification according to whether completely available (Class I) or partly unavailable due to lignitication (Class II)
or unavailable (Class III).
FEED CARBOHYDRATE FRACTIONS
Cellulose
Hemicellulose
Pectin
Fructans
Starch
RUMEN FERMENTATION
Pentoses
Cellobiose
Uronic
Galactose
Dextrans
acids
Sucrose
Pentose
pathway
Fructose
Maltose
Glucose
Pyruvate
Formate
ATP
Lactate
Oxalacetate
CO2
Malate
Acetyl-CoA
H2
Fumarate
+ ATP
AcetoSuccinate
acetyl-CoA
ATP
Succinyl - CoA
Acetaldehyde
ATP
Methylmalonyl-CoA
2 ATP
CH4
Propionyl-CoA
Ethanol
Acetate
+ 2H
Butyrate
+ ATP
Propionate
Acrylate
FORAGE QUALITY STANDARDS
Quality
Standard
CP
ADF2
Prime
1
2
3
4
5
>19
17-19
14-16
11-13
8-10
<8
<31
31-35
36-40
41-42
43-45
>45
1
NDF2
DDM3
%of DM
<40
>65
40-46
62-65
47-53
58-61
54-60
56-57
61-65
53-55
>65
<53
1
DMI4
RFV
Index 5
>3.0
3.0-2.6
2.5-2.3
2.2-2.0
1.9-1.8
<1.8
>151
151-125
124-103
102-87
86-75
<75
Standard assigned by Hay Marketing Task Force of AFGC.
2
ADF = acid detergent fiber; NDF = neutral detergent fiber.
3
Digestible dry matter (DDM, %) = 88.9 - (0.779 x ADF%).
4
Dry matter intake (DMI, % of body weight) = 120 + forage NDF (% of DMI).
5
Relative feed value (RFV) calculated from DDM x DMI + 1.29. Reference
RFV of 100 = 41% ADF and 53% NDF.
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)
CORN PLANT - GROWTH/MATURITION
{
Fully dented
Kernel
Grain
Late dough/early dent
Blister
Growth
Cobs & Silk
Stalk & Tassel
Leaves
{
20
40
60
Maturity/Days
80
110
120
Plant
0
10
35
% Dry Matter
Harvest for silage
{
Late Dough/early dent
35% DM
100
SILAGE FERMENTATION
PHASE 1.
PHASE 4.
Cell respiration
lactic acid
production of CO2
PHASE 5.
formation
production of heat
depends upon phase 4
if enough lactic acid
PHASE 2.
Production of
was formed, the silage
acetic acid
remains constant
PHASE 3.
If insufficient acid was
formed, butyirc acid
production begins
lactic acid
formation begins
69°F
90°F
Temperature Change
84°F
Protein may be broken
down and spoilage may be
excessive
pH Change
6.0
4.0
4.2
ACETIC ACID
BACTERIA
3.8
LACTIC ACID
BACTERIA
RATE OF SEEPAGE LOSS
1
2
3
4
7
12
AGE OF SILAGE (days)
20
SILAGE FERMENTATION
Major
Organisms
Entero bacteria
Substrates
Water soluble carbohydrate (WSC)
End products
Acetic acid, CO2, H2, ETOH
Lactic acid bacteria
WSC
Lactic acid, acetic acid, CO2
Acetobacter
Acetic acid, lactic acid
CO2, H2O
Clostridia
WSC, proteins, lactic acid
Butyric acid, amines, CO2
Yeasts
Lactic acid, starch, WSC
Ethanol, CO2
Molds
Lactic acid, WSC
CO2
SILAGE PRODUCTION
CROP
Microbes Resonsible for
Aerobic Deterioration
Yeast, acetobacter, bacilli
Type
Grain silages a
Comments
High WSC
Fast drop in pH
Attains very low pH (3.6 to 3.9)
Poor aerobic stability
Grass silages
Low WSC
Difficult to wilt
Poor aerobic stability
Yeast and molds
Legume
Low WSC
High buffering capacity
Slow drop in pH
Moderate extent of pH drop (4.2 to 4.9)
Yeast and molds
a
corn, wheat, barley
HARVEST DRY MATTER (DM) AFFECTS SILAGE QUALITY
<30%
Direct-cut
Seepage
Clostridial growth
Protein degradation
Freeze potential
Heavy acid load
Low pH
Harvest DM content
30 to 45%
Moderate wilt
No seepage
>30% DM no clostridia
Moderate fermentation
>55%
Heavy wilt
No seepage
Packing problems
Fermentation curtailed
Molding/aerobic
Instability
Heat damaged N
High pH
PUTTING UP SILAGE
Storage Structure
Oxygen - limiting
Characteristics
Very expensive
Good for haylage (55% DM)
Upright/Stave
Lower cost
Good for corn silage (35% DM)
Bunker/Trench
Inexpensive
Bags
Adds flexibility
Disposal problem
Forage Losses
16%
17%
22 - 25%
17%
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%
=
.45 - .75% =
safe to feed
feed with caution
introduce to ration gradually
increase concentrate ratio to dilute
restrict single meal size
> 1.00%
=
Don’t feed
Harvesting methodology in a drought
• Don’t 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