Sarah Kenyon
Agronomy Specialist
417-967-4545
[email protected]
Plant Growth
or Yield
Putting it
Together
Quality
Plant Growth
or Yield
Sun
CO2
O2
CHO
H2 O
Mineral Nutrients
9 Macronutrient elements:
C H O N K P Ca Mg S
8 Micronutrient elements:
Mn Zn Cu Cl B Fe Mo Ni
Some other elements that are beneficial:
Na Si V Co Al
Grass Anatomy
Iowa State University Extension PM 1791
Tillers
Initially, tillers depend on
carbohydrates developed the
previous fall. Then as leaf area
explodes with additional tillers, new
sugars are made
Legume Anatomy
Iowa State University Extension PM 1791

3 primary stages of forage development
1. Vegetative





Tillers emerge from buds in the crown
Tiller growth uses stored carbohydrates
Plants begin making new sugars
Most new sugars supplement carbohydrates
to help growth
Very little if any is put into storage





Leaves get longer
New tillers grow from buds, tillers branch
More leaf area speeds up photosynthesis
Some new sugars continue to be used in
growth
Some new sugars stored as carbohydrates

3 primary stages of forage development
1. Vegetative
2. Elongation/Jointing




Leaf growth slows down
Photosynthesis continues making sugars
Most new sugars stored as carbohydrates
Reproductive tillers begin to elongate

3 primary stages of forage development
1. Vegetative
2. Elongation/Jointing
3. Reproductive




Leaf growth stops, formation of stems and
reproductive structures
Photosynthesis continues making sugars
Most new sugars used for seed production
Little stored carbohydrates used for seed
development

Perennial
◦ Production of Seeds
◦ Vegetative
 Tillers
 Rhizomes

Annual
◦ Production of Seeds
Iowa State University Extension PM 1791

3 primary stages of forage development
1. Vegetative
2. Elongation/Jointing
3. Reproductive




In Tall Fescue – growing point are not removed
In Tall Fescue – residual stubble contains chloroplasts
In Alfalfa – many auxiliary buds (growing points) are
removed
In Alfalfa – most chloroplasts are gone





In both plants – regrowth seen in light green
In Tall Fescue – regrowth from intact growing points
In Tall Fescue – regrowth uses some stored
carbohydrates
In Alfalfa – regrowth from basal buds
In Alfalfa – regrowth uses most stored carbohydrates
Dry Matter Yield at Various Cutting Heights
Dry Matter Yield (lb/acre)
12000
10000
1 inch
2 inches
8000
3 inches
6000
4 inches
4000
5 inches
2000
6 inches
0
Per. Ryegrass
Tall Fescue
Species
% Leaf
% Root Growth
Removed
Stopped
10
20
30
40
50
60
70
80
90
To remain healthy,
30% of grass root
systems must be
replaced annually.
0
0
0
0
2 to 4
50
78
100  Stops root growth 12 days
100  Stops root growth 18 days
Overgrazing is removing too much of the
Dry Matter
Yield at Various
Cutting Heights
canopy
too often
Dry Matter Yield (lb/acre)
12000
10000
1 inch
2 inches
8000
3 inches
6000
4 inches
4000
5 inches
2000
6 inches
0
Per. Ryegrass
Tall Fescue
Species

Cool Season Grasses
◦ Tall Fescue
◦ Orchardgrass

Warm Season Grasses
◦ Native Grasses
◦ Bermudagrass

Annuals
◦ Pearl Millett
◦ Winter Wheat
Take Half / Leave Half
Residual

Allows plant to recover completely after
grazing
◦ Recovery of shoots and roots

Allows for plant and stand persistence
During grazing periods: control stubble height
•
•
•
Keep growing points
Provide for good photosynthesis
Keep roots growing
Between grazing periods: schedule rest periods
•
•
•
Allows for photosynthesis
Allows leaves to regrow
Vegetative reproduction can occur

Short-lived perennials reseed
◦ Red Clover

Annuals reseed
◦ Annual Lespedeza, Crabgrass

Grasses are given the chance to spread
◦ Bermudagrass

Plants are allowed to thicken naturally by
reseeding
www.agriseed.co.nz

Incorporates a grazing strategy and
rest periods
◦ Quality & quantity increases
◦ Enhanced forage utilization
◦ Persistence increases
Quality
Working definition:
“high protein, low fiber”
Measured Components
• Acid Detergent Fiber (ADF) =
cellulose & lignin
• Neutral Detergent Fiber (NDF) =
total cell walls =
cellulose, lignin & hemicellulose
• Nitrogen
• Minerals
• Antiquality
Calculated Components
• Net Energy (NE)
calculated from ADF
• Total Digestible Nutrients
(TDN)
calculated from ADF
• Digestible Dry Matter (DDM)
calculated from ADF
• Dry Matter Intake (DMI)
calculated from NDF
• Relative Feed Value (RFV)
calculated from NDF & ADF
• Crude Protein (CP)
calculated from Nitrogen
1. Maturity
The sharpest decrease in quality occurs
during
the reproductive phase.
CP = 13 – 14%
CP = 5 - 6%
During this growth phase plants lose
quality by the hour!

What is the boot stage?
Changes in botanical composition and forage quality of forage
groups at different maturity stages.
Forage Group
Grasses
Vegetative
Boot
Heading
Mature
Legumes
Vegetative
Bud
Early Flower
Late Flower
Source: Schroeder, 1996
Leaves
CP
NDF
------------------------% DM----------------------> 50
40 - 50
30 - 40
20 - 30
> 18
13 - 18
8 - 12
<8
< 55
55 - 60
61 - 65
> 65
40 - 50
35 - 45
25 - 40
< 30
> 19
17 - 19
13 - 16
< 13
< 40
40 - 46
47 - 51
> 51
•When 4th leaf emerges, the first leaf begins to die
•Most grasses will have no more than 3 live leaves
any point in time
•Pasture quality begins to decline and is wasted
The 3 to 3½ leaf stage is the
optimum stage for grazing
www.agriseed.co.nz
Iowa State University Extension PM 1791
1. Maturity
2. Plant Part
1st bite: leaves with low fiber
2nd bite
3rd bite: stems with high fiber
CP
NDF
NeL
1st bite: leaves low fiber
27.4
38.5
0.79
2nd bite
22.9
44.6
0.76
3rd bite: stems high fiber
14.0
60.0
0.67
Crude Protein Content of Pastures
12-Paddock Rotation
Variation in Milk Production Between
Pastures
Dry Matter Yield at Various Cutting Heights
Dry Matter Yield (lb/acre)
12000
10000
1 inch
2 inches
8000
3 inches
6000
4 inches
4000
5 inches
2000
6 inches
0
Per. Ryegrass
Tall Fescue
Species
Dry Matter Yield at Various Cutting Heights
Dry Matter Yield (lb/acre)
12000
10000
1 inch
2 inches
8000
3 inches
6000
4 inches
4000
5 inches
2000
6 inches
0
Per. Ryegrass
Tall Fescue
Species
1. Maturity
2. Plant Part
3. Species




Annual & Perennial
Cool-Season & Warm-Season
Grasses & Legumes
Forbs & Browse
Palatability of Cool-Season Forage Grasses – Univ. of Wisconsin
Specie
Variety
Palatability*
Orchardgrass
TAKENA
4.3
Timothy
CLIMAX
4.3
Perennial Ryegrass
KEMAL
4.2
Orchardgrass
BARIDANA
4.0
Orchardgrass
DAWN
4.0
Perennial Ryegrass
ANACONDA
4.0
Smooth bromegrass
BLIZZARD
3.8
Orchardgrass
BENCHMARK
3.7
Timothy
DOLINA
3.7
Orchardgrass
HAYMATE
3.5
Orchardgrass
WARRIOR
3.0
Smooth bromegrass
ALPHA
2.3
Tall fescue
KY 31
1.4
Tall fescue
BRONSON
1.2
Tall fescue
SEINE
0.6
*Palatability rating 0=0% grazed, 1=20%, 2=40%, 3=60%, 4=80%, 5=100% grazed. Palatability of grasses under
grazing is determined by visual estimation of percent defoliation of plots. The visual determination is made
midway during mob grazing by beef cows of the grass plots for yield determination.
1.
2.
3.
4.
Maturity
Plant Part
Species
Anti-quality Factors

Nutrient Deficiency
◦ Grass Tetany


Weeds
Poison Compounds
◦ Nitrate Poisoning
◦ Prussic Acid


Bloat
Fescue Toxicosis




Early spring production
Medium to high yield
Excellent persistence
Good tolerance to:
◦
◦
◦
◦
◦
◦
◦
Poor drainage
Low soil fertility
Drought
Heat stress
Cold temperatures
Insects
Nematodes




Fungus found in stem, leaf sheaths & seed
Increases progressively season long
Minimized in young growth
Cannot survive outside of the plant host
Roberts and Andrae, 2004
www.agricom.co.nz

Mutualistic Symbiosis
◦ Plant providses habitat and nutrition for the
endophyte
◦ Endophyte (fungus) provides plant with multiple
benefits





Drought Tolerance
Insect Resistance
Increase Nutrient Acquisition
Grazing Tolerance
Others

Produces alkaloids which confer pasture pest
resistance but can also cause animal health
problems
◦ Peramine
◦ Lolines
◦ Ergovaline

Medicinal Alkaloids
◦ Morphine, quinine, atropine, vincristine

Addictive Alkaloids
◦ Cocaine, heroin, caffeine, nicotine

Very toxic in small amounts
◦ Strychnine, coniine







Lower conception rates
Reduced milk production
Reduced feed intake
Rough hair coat
Increased core body temperature in summer
(leads to heat stress)
Frozen nose, ears, tails, etc (in winter)
Fescue foot



US beef industry over $600 million annually
Missouri beef industry over $160 million
annually
All US livestock sectors over $1 billion
(Roberts and Andrae, 2010)

Test
 < 20% = Low Infection
 > 55% = High Infection
Endophyte generally necessary for
persistence south of this line
(West, 1998)
Bouton et al., 2002
www.noble.org

Non-toxic endophytes (Novel or Friendly)
◦ Retain persistent qualities
◦ Animal performance similar to E-

Available Varieties:
◦
◦
◦
◦
Jesup Tall Fescue with MaxQ
Advance with AR37
Bar-Optima with E34
Others
Location
Fayetteville, AR
Mt. Vernon, MO
AR4
EE+
Average Daily Gain (lb)
1.43
1.55
0.93
1.21
1.21
0.55
West et al., 1998
Roberts and Andrae, 2004
1.
2.
3.
4.
Maturity
Plant Part
Species
Anti-quality Factors
Plant Growth
or Yield
Putting it
Together
Quality

Monitor forage before,
during and after the
grazing event
◦ Determines forage
availability for livestock
◦ Identifies which paddocks to
graze, rest, and cut for hay
◦ Helps to prevent overgrazing
◦ Helps to identify weak
pasture stands

Monitor pastures at
least twice a month
◦ Weekly is better

Walking is better than
driving

Forage available for livestock in KNOWN
Able to construct pasture budgets and
establish paddock rotations

Able to Adjust:

◦ Forage Allocation
◦ Number of Cattle in Paddock
◦ Number of Days for Grazing

Write down pasture measurements and
management decisions
◦ Rest Periods
◦ Number of Cattle on Pasture/ Days Cattle are on
Pasture
◦ Forage Demand
◦ Paddock Rotation Schedule
◦ Many More

Write down pasture measurements and
management decisions

Grazing Wedge
◦ http://plantsci.missouri.edu/grazingwedge/


Ranchers should adopt the philosophy that
pasture production is their business.
Therefore, the health of the pastures is the
most important aspect of ranching.
THANK YOU!

Observe pasture growth regularly
◦ Yield
◦ Stand Density and Health
◦ Over time can help to identify:
 Low producing paddocks
 Need to weed control
 Management strengths and weaknesses
Allow adequate rest between grazing
for plant recovery
 Begin Grazing at the 3 – 3 ½ leaf stage
 Harvest hay during the boot stage
 Manage stands for improved pasture
quality
 Keep pasture records!!!

Questions?