Sarah Kenyon

Agronomy Specialist

417-967-4545

KenyonS@missouri.edu

Plant Growth or Yield

Quality

Putting it Together

Plant Growth or Yield

Sun

CO2

H2O

O2

CHO

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

0

2000

4000

6000

8000

10000

12000

Per. Ryegrass Tall Fescue

Species

Dry

Matt

er

Yie

ld (

lb/a

cre

)

1 inch

2 inches

3 inches

4 inches

5 inches

6 inches

% Leaf Removed

% Root Growth Stopped

10 0

20 0

30 0

40 0

50 2 to 4

60 50

70 78

80 100

90 100

Stops root growth 12 days

Stops root growth 18 days

To remain healthy,

30% of grass root

systems must be

replaced annually.

Dry Matter Yield at Various Cutting Heights

0

2000

4000

6000

8000

10000

12000

Per. Ryegrass Tall Fescue

Species

Dry

Matt

er

Yie

ld (

lb/a

cre

)

1 inch

2 inches

3 inches

4 inches

5 inches

6 inches

Overgrazing is removing too much of the canopy too often

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

CP = 13 – 14% CP = 5 - 6%

The sharpest decrease in quality occurs during the reproductive phase. 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 Leaves CP NDF

------------------------% DM-----------------------

Grasses

Vegetative > 50 > 18 < 55

Boot 40 - 50 13 - 18 55 - 60

Heading 30 - 40 8 - 12 61 - 65

Mature 20 - 30 < 8 > 65

Legumes

Vegetative 40 - 50 > 19 < 40

Bud 35 - 45 17 - 19 40 - 46

Early Flower 25 - 40 13 - 16 47 - 51

Late Flower < 30 < 13 > 51

Source: Schroeder, 1996

•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

1st bite: leaves with low fiber

2nd bite

3rd bite: stems with high fiber

1. Maturity 2. Plant Part

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

CP NDF NeL

Crude Protein Content of Pastures

12-Paddock Rotation

Variation in Milk Production Between Pastures

Dry Matter Yield at Various Cutting Heights

0

2000

4000

6000

8000

10000

12000

Per. Ryegrass Tall Fescue

Species

Dry

Matt

er

Yie

ld (

lb/a

cre

)

1 inch

2 inches

3 inches

4 inches

5 inches

6 inches

Dry Matter Yield at Various Cutting Heights

0

2000

4000

6000

8000

10000

12000

Per. Ryegrass Tall Fescue

Species

Dry

Matt

er

Yie

ld (

lb/a

cre

)

1 inch

2 inches

3 inches

4 inches

5 inches

6 inches

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. Maturity 2. Plant Part 3. Species 4. 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

(West, 1998)

Endophyte generally necessary for

persistence south of this line

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

AR4 E- E+ Location Average Daily Gain (lb) Fayetteville, AR 1.43 1.55 0.93 Mt. Vernon, MO 1.21 1.21 0.55

West et al., 1998

Roberts and Andrae, 2004

1. Maturity 2. Plant Part 3. Species 4. Anti-quality Factors

Plant Growth or Yield

Quality

Putting it Together

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?