Dr. Dennis Hancock Extension Forage Specialist

Crop and Soil Sciences – UGA

Dr. Dennis Hancock Extension Forage Specialist

Crop and Soil Sciences – UGA

Keys to Maximizing Your

RFQ Score

Keys to Maximizing Your

RFQ Score

What is the difference?What is the difference?

1) Digestible energy2) How much can be eaten

What is “high quality forage?”

What is “high quality forage?”

• Forage that is highly digestible (i.e., high TDN)

• Large amounts of the forage can be consumed (i.e., high DMI).

• Relative Forage Quality (RFQ) =

TDN * DMI/1.23

• Forage that is highly digestible (i.e., high TDN)

• Large amounts of the forage can be consumed (i.e., high DMI).

• Relative Forage Quality (RFQ) =

TDN * DMI/1.23

Relative Forage Quality (RFQ)75 100 125 150 175 200 225

• Heifer, 18-24 mo.• Dry cow• Mature horse, lt. work

• Heifer, 12-18 mo.• Lactating beef cow• Lactating mare• Mature horse, mod. work

• Dairy, last 200 days• Heifer, 3-12 mo.• Stocker cattle• Weanling horse• Mature horse, int. work

• Dairy, 1st 120 days• Dairy calf

Qu

ality

Req

uir

ed

What Affects Forage Quality?What Affects Forage Quality?

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Fertilization Provide fertilizer based on soil test recommendations

Variety Use varieties that have proven to be higher in quality.

The Paradox of Forage Quality and Quantity

Days of Growth

0 5 10 15 20 25 30 35 40 45 50

For

age

Mas

s(d

ry lb

s/a

cre

)

0

2000

4000

6000

8000

10000

12000Growth Curve

Digestibility & Palatability

Fescue Maturity- Effects on Yield and Protein

Fescue Maturity- Effects on Yield and Protein

Late boot Early flower Seed dough0.0

0.5

1.0

1.5

2.0

2.5

3.0

0

2

4

6

8

10

12

14

16

Yield Crude Protein

Maturity

Tons

/Ac

Cru

de P

rote

in,

%

Fescue Maturity- DigestibilityFescue Maturity- Digestibility

Late boot Early flower Seed dough0.0

0.5

1.0

1.5

2.0

2.5Digested DM/Ac

Tons

/Acr

e

Majority of hay harvested at hard seed stageOnly truly applicable with spring harvest

JUST MORE MANURE!!!

Bermudagrass Harvest Interval: Effects on Protein

and Digestibility

Crude Protein Digestibility0

10

20

30

40

50

60

15.8

55.0

6.3

49.0

5.3

45

4 weeks 8 weeks 13 weeksMcCollough and Burton., 1962DMI 11.9, 8.8, 9.5 lbsADG 1.2, .9, 0 lbs

Perc

ent,

%

Bermudagrass Harvest Interval: Effects on Yield and

Protein

Bermudagrass Harvest Interval: Effects on Yield and

Protein

Yield, T/Ac Crude Protein, % Crude Protein, T/Ac

02468

1012141618

4.8

16.1

0.8

6.4

12.4

0.8

3 weeksHoveland et al., 1971

Forage Quality has High Value Now

Forage Quality has High Value Now

Crop Maturity CP TDNSupplement

† Cost‡

-- % -- -- % -- lbs/hd/day $/hd/day

Bermudagrass

4 weeks 10-12 58-62 0 $0

6 weeks 8-10 51-55 4.8 $0.45

8 weeks 6-8 45-50 7.5 $0.72

Tall Fescue Late boot 14-16 66-70 0 $0

Early head

11-13 60-63 0 $0

Dough 8-10 50-54 5.3 $0.50† Assuming soyhulls supplementation for forage quality on low end of the range.

‡ Approximate prices for 2010.

Supplementing a Lactating Beef Cow

+ ~$1.40/hd/d

Harvest Timing Recommendations

Harvest Timing Recommendations

•Hybrid Bermudagrass- 1st cut at 12-16 inches- Subsequent cuttings at 3.5-5 week intervals

• Tall fescue, ryegrass, orchardgrass, etc.

- Spring cut at early flower stage - Mid to late boot stage for higher quality - Subsequent cuttings at 10-12 inches (better

quality)

• Alfalfa- Spring cut at when 10-20% of plants are

blooming- Cut at late bud – 10% bloom stage

•Hybrid Bermudagrass- 1st cut at 12-16 inches- Subsequent cuttings at 3.5-5 week intervals

• Tall fescue, ryegrass, orchardgrass, etc.

- Spring cut at early flower stage - Mid to late boot stage for higher quality - Subsequent cuttings at 10-12 inches (better

quality)

• Alfalfa- Spring cut at when 10-20% of plants are

blooming- Cut at late bud – 10% bloom stage

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Fertilization Provide fertilizer based on soil test recommendations

Variety Use varieties that have proven to be higher in quality.

Quality Differences in the Major Forage Species

Quality Differences in the Major Forage Species

40

50

60

70

80

Dig

estib

le D

M, %

Trop

ical Annual

Grasses

Cool S

eason P

erennial

G

rasses

Cool S

eason A

nnual G

rasses

Leg

um

es

Tropical P

erennial

Grasses

Maint.

Mod. Production

High Production

Typical Range in Quality of

Common Forages

Typical Range in Quality of

Common Forages

Relative Forage Quality (RFQ)

Summer Annual Grass

Bermudagrass

Cool Season Peren. Grasses

Other Legumes

Alfalfa

75 100 125 150 175 200 225

Cool Season Annual Grasses

Qu

ality

Pro

vid

ed

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Fertilization Provide fertilizer based on soil test recommendations

Variety Use varieties that have proven to be higher in quality.

14 inches

~74% of the bales volume is contained in that 14 inches.

Moisture distribution of mixed grass-legume round bales

stored on the ground

Moisture distribution of mixed grass-legume round bales

stored on the ground

Shinners, University of Wisconsin

Twine Wrapped

% Moisture

Net Wrapped

Moisture distribution of mixed grass-legume round bales stored on the ground vs.

elevated

Moisture distribution of mixed grass-legume round bales stored on the ground vs.

elevated

Shinners, University of Wisconsin

Twine Wrapped

% Moisture

On a Pallet

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Fertilization Provide fertilizer based on soil test recommendations

Variety Use varieties that have proven to be higher in quality.

The Effect of Rainfall on DM Loss

The Effect of Rainfall on DM Loss

DM

Loss,

%

Rainfall, in.Scarbrough et al., 2005

Crop Moisture Lessens Rain Damage on Bermudagrass

Crop Moisture Lessens Rain Damage on Bermudagrass

DM

Loss,

%

Rainfall, in.Scarbrough et al., 2005

76% Moisture, Not Significant.

40% Moisture

13% Moisture

Crop Moisture Lessens Rain Damage on Bermudagrass

Crop Moisture Lessens Rain Damage on Bermudagrass

ND

F, %

Rainfall, in.Scarbrough et al., 2005

76% Moisture, Not Significant.

40% Moisture

13% Moisture

The Effect of Rain on Tall Fescue Hay

The Effect of Rain on Tall Fescue Hay

No RainRain

DamageIntake, % of b.w.

2.10 1.92

NDF, % 68.1 76.0

Digestibility, % 63.2 59.7

Turner et al., 2003

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Fertilization Provide fertilizer based on soil test recommendations

Variety Use varieties that have proven to be higher in quality.

Heat Damage to Crude Protein

Heat Damage to Crude Protein

Heat

Pro

tein

Useable Protein

Heat-DamagedProtein

DM Intake

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Variety Use varieties that have proven to be higher in quality.

Variety Use varieties that have proven to be higher in quality.

Yield and Digestibility of Bermudagrass Hybrids

Yield and Digestibility of Bermudagrass Hybrids

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Variety Use varieties that have proven to be higher in quality.

Fertilization Provide fertilizer based on soil test recommendations

CP in Bermudagrass Forage as Effected by N FertilizationCP in Bermudagrass Forage as Effected by N Fertilization

Source: Dr. Bill Anderson, USDA-ARS Tifton

Effect of N Rates on Bermudagrass CP &

Digestibility

Effect of N Rates on Bermudagrass CP &

Digestibility

0 400 14000

5

10

15

20

25

5052545658606264666870

Crude Protein Digestibility

Annual lbs N/year

Crud

e Pr

otei

n, %

Digestibility, %

Burton et al.

Does fertility or harvest timing affect quality more?- Crude Protein

Does fertility or harvest timing affect quality more?- Crude Protein

Colovos et al. 1961

(4X as much N)

Bromegrass

Does fertility or harvest timing affect quality more?-

Digestibility

(3.8 X as much N)

Colovos et al. 1961Bromegrass

Primary Factors Affecting Forage Quality

Primary Factors Affecting Forage Quality

Factor Recommendation

Plant Maturity Cut bermudagrass every 4-5 wks; cut tall fescue in the boot or early head stage.

Forage Species Use the highest-quality species that will persist in your environment.

Bale Storage Protect bales from rainfall and weathering during storage (i.e., barn, tarp, etc.)

Rain During Curing

Avoid cutting if significant rainfall (> 0.50 inches) is predicted during curing.

Moisture at Baling

Allow forage to dry to the appropriate moisture (Round: 15%; Square: 18%)

Variety Use varieties that have proven to be higher in quality.

Fertilization Provide fertilizer based on soil test recommendations

Be Careful of Cutting Height

Be Careful of Cutting Height

Parting ThoughtsParting Thoughts

• RFQ is chiefly defined by digestibility and DM intake

• Plant maturity trumps ALL other factors- Even more important than

forage species

• Rain damage is a problem, but letting a plant get overly mature to avoid a ½ inch rain is even more problematic

• Avoid cutting the forage too short- It reduces quality and slows the

rate of regrowth

QUESTIONS?

www.georgiaforages.co

m

www.georgiaforages.co

m