U.S. Quality Grades

• Sex Class

• Maturity

• Marbling

• Firmness

Purpose of Grading

• Facilitate the marketing of meat

• To sort carcasses from a heterogeneous population into homogeneous groups

Sex Class DeterminationSteer vs Heifer

Trait Steer Heifer

Pizzle eye Present Absent

Semimembranosus Square shaped

Bean shaped

Secondary sex fat depot

Rough, grape-like

Smooth in appearance

USDA Beef Quality Grades

• Quality grades are an estimate of beef palatability

Beef Palatability

• Tenderness

• Juiciness

• Flavor

USDA Quality Grades• Grades of Youthful Carcasses (< 42 mos.)

Prime

Choice

Select

Standard

• Grades of Mature Carcasses (> 42 mos.)Commercial

Utility

Cutter

Canner

USDA Quality GradesBased on consideration of two general

factors:

1. Physiological Maturity• Skeletal Maturity

• Lean Maturity

2. Marbling (Intramuscular Fat)• Amount

• Distribution

USDA Beef Grades

• Maturity Scores:

– A Youngest

– B – C– D– E Oldest

USDA maturity and marbling scores

Marbling scores: (Highest to lowest)-Abundant -Moderately Abundant -Slightly Abundant -Moderate-Modest-Small-Slight-Practically Devoid -Devoid

Relationship between tenderness and USDA maturity scores

A B C D E

Maturity

Sh

ea

r F

orc

e V

alu

es

Physiological Maturity vs Chronological Maturity

• The physiological maturity of the carcass is an estimate of the actual chronological age of the animalUSDA Maturity Score Estimated chronological age

A 9 to 30 months

B 30 to 42 months

C 42 to 72 months

D 72 to 96 months

E 96 or more months

Physiological Maturity• Skeletal Maturity is determined by

evaluating the condition of the cartilage in the vertebral column, with heavy emphasis placed on the cartilaginous buttons at the end of the thoracic vertebra

• Lean maturity is determined by the color and firmness of the ribeye at the 12th 13th rib interface

Beef Skeletal MaturityMaturityMaturity

A00 0% 9 – 30

B00 10% 30 – 42

C00 35% 42 – 72

D00 70% 72 – 96

E00 90%

E100 100%

A00 0% 9 – 30

B00 10% 30 – 42

C00 35% 42 – 72

D00 70% 72 – 96

E00 90%

E100 100%

% Thoracic Ossification% Thoracic Ossification

Approximate Age (Months)Approximate Age (Months)

> 96

Skeletal Maturity:Skeletal Maturity:A00A00 B00B00 C00C00 D00D00 E00E00

Beef Skeletal Maturity

• Physiological Skeletal Ossification is only marginally related to chronological age of the live animal.

“A” and “B” Maturity Carcass Thoracic Chine Buttons

“A” and “B” Maturity Carcass Thoracic Chine Buttons

““A” MaturityA” Maturity

““B” MaturityB” Maturity

A B C D ESACRAL DISTINCT

SEPARATION

LUMBAR NO

OSSIFICATION

THORAIC NO

OSSIFICATION

Physiological Maturity of Lumbar Vertebrae of from carcasses with A40 and

A50 Overall Maturity Scores

A40 A50

A B C D ESACRAL DISTINCT

SEPARATION

FUSED

LUMBAR NO

OSSIFICATION

NEARLY

COMPLETELY

OSSIFIED

COMPLETELY

OSSIFIED

THORAIC NO

OSSIFICATION

SOME

OSSIFICATION

PARTIAL

OSSIFICATION

CONSID.

OSS.

OUTLINES

PLAINLY

VISIBLE

CONSID.

OSS.

OUTLINES

BARELY

VISIBLE

A B C D ERIBS SLIGHT

TENDENCY

TOWARDS

FLATNESS

SLIGHTLY

WIDE

AND

FLAT

TEXTURE FINE TENDS TO

BE FINE

SLIGHTLY COARSE

MOD.

COARSE

COARSE

COLOR OF LEAN

MOD.

LIGHT RED

SLIGHTLY

DARK

RED

MOD.

DARK

RED

DARK

RED

Skeletal Maturity

A B C D E

Sacral Distinct separation

Some separation

Fused Fused Fused

Lumbar No ossification

Partial ossification

Mostly ossified

Ossified Ossified

Thoracic* 0-10% 10-35% 35-70% 70-90% 90% +

*Average ossification of first three thoracic vertebra

“Buttons”

Spinous Spinous process of process of the Thoracic the Thoracic vertebra vertebra

Thoracic Thoracic vertebravertebra

Beef Quality Grades- Lean Maturity

Young Intermediate Mature

A00 B00 C00 D00 E00

Various Maturity of Beef Cattle

A-MaturityA-Maturity C-MaturityC-Maturity D-MaturityD-Maturity

Overall USDA Maturity

A-MaturityA-Maturity

Overall USDA Maturity

• Combine Skeletal & Lean– Average– If within 40 degrees- simple average– > 40 degrees- average the degrees then adjust

10 degrees toward bone– If average of Skeletal & Lean crosses C/B line,

& skeletal is C- it stays with the skeletal side– Overall maturity cannot differ more than 1 full

maturity from skeletal

USDA Quality-Marbling

• Marbling, or intramuscular fat flecks within the exposed ribeye area

• Usually the major factor determining quality grade

Flecks of fat within the encircled area

Marbling

Slight00 Small00 Modest00

Moderate00 Moderately Abundant00Slightly Abundant00

USDA Quality Grades

Quality Grade

Quality Grade

Click to add textClick to add text A B C EDAbundantAbundant

Mod. Abund.Mod. Abund.

Sl. Abund.Sl. Abund.

ModerateModerate

ModestModest

SmallSmall

SlightSlight

TracesTraces

Pract. Dev.Pract. Dev.

Marbling

Maturity

Prime

Choice

Select

Standard

Commercial

Utility

Click to add textClick to add text A B C EDAbundantAbundant

Mod. Abund.Mod. Abund.

Sl. Abund.Sl. Abund.

ModerateModerate

ModestModest

SmallSmall

SlightSlight

TracesTraces

Pract. Dev.Pract. Dev.

Marbling

Maturity

Prime

Choice

Select

Standard

Commercial

Utility

Overall USDA Maturity

• Determining Final Quality Grade– A maturity overall- Marbling determines

Quality grade– It takes a greater amount of marbling to

compensate for added maturity to receive same Quality grade

– Overall maturity should be adjusted back to respective Maturity 00 also creating an adjusted marbling score

Overall USDA Maturity• Determining Final Quality Grade

– Special rule- 1997- B maturity overall with SM or SL marbling = High Std

– Everything else adjusted back to respective Maturity 00

C D E

MD SLAB MAB

MT MD SLAB

SM MT MD

SL SM MT

TR SL SM

PD TR SL

USDA Yield Grades

Beef Yield Grades

• USDA Yield Grades predict the percentage of carcass weight in boneless, closely trimmed retail cuts from the round, loin, rib and chuck

• Lean : Fat + Bone

USDA Yield Grades

Yield/Cutability estimates are determined using four criteria– Hot Carcass Weight, lbs– Adjusted Fat Thickness, in.– Ribeye Area, in2

– % KPH

History

• USDA developed the cutability equation but it was not used because it was hard to sort carcasses based on percentage cutability.

• So, they developed the equation to estimate yield grade and used those grades (1,2,3,4,5) to sort carcasses

USDA Yield Grade

USDA YG %BCTRC

1

2

3

4

5

52.3 % or More

52.3 - 50.0%

50.0 - 47.7%

47.7 - 45.4%

45.4% or Less

%BCTRC =51.34 – 5.784(Adj.Fat) – 0.462(KPH) + 0.740(REA) – 0.0093(HCW)

USDA YG =2.5 + 2.5(Adj.Fat) + 0.2(KPH) - 0.32(REA) + 0.0038(HCW)

USDA Yield Grade

• First- First- We Will Use the 3-Step Short-Cut Method to determine USDA Yield Grade

• 4 parameters utilized in beef yield grades

– HCW– REA– Adj. Fat Thickness– % KPH

USDA Yield Grade

Step 1- Determine Preliminary YG (PYG)

PYG= 2.0 + 0.25 YG for every 0.1” of fat

NOTE: Report all PYG to the nearest tenth of a PYG- round up

Example- 0.3”= PYG- 2.75

2.75= 2.8

Fat Thickness PYG

0.0 2.0

0.1 2.25

0.2 2.5

0.3 2.75

0.4 3.0

0.5 3.25

0.6 3.5

0.7 3.75

0.8 4.0

0.9 4.25

1.0 4.5

1.1 4.75

1.2 5.0

USDA Yield GradeStep 2- Determine Ribeye

(REA) adjustment/ Hot Carcass Wt (HCW)

IF INBETWEEN WTS- USE 9-8-8 Rule

EXAMPLE- 608 lbs needs 11.0; 609 lbs needs 11.1

616 lbs needs 11.1; 617 lbs needs 11.2

Carcass Wt Req. REA

550 10.4

575 10.7

600 11.0

625 11.3

650 11.6

675 11.9

700 12.3

725 12.5

750 12.8

775 13.1

800 13.4

825 13.7

850 14.0

875 14.3

900 14.6

925 14.9

950 15.2

USDA Yield GradeStep 2- Continued- Determine

Ribeye (REA) adjustment/ Hot Carcass Wt (HCW)

Req. REA- Actual REA =Adj. Factor

3

ONLY Tenths of a YG Adjustment

Actual > Req. = Subtract Adj Factor

Req. > Actual= Add Adj Factor

Carcass Wt Req. REA

550 10.4

575 10.7

600 11.0

625 11.3

650 11.6

675 11.9

700 12.3

725 12.5

750 12.8

775 13.1

800 13.4

825 13.7

850 14.0

875 14.3

900 14.6

925 14.9

950 15.2

USDA Yield GradeStep 2- Example

717 lb carcass needs 12.4 in REA

Actual REA- 15.3

12.4 – 15.3 = .966

3

Adj Factor= -1.0

Carcass Wt Req. REA

550 10.4

575 10.7

600 11.0

625 11.3

650 11.6

675 11.9

700 12.3

725 12.5

750 12.8

775 13.1

800 13.4

825 13.7

850 14.0

875 14.3

900 14.6

925 14.9

950 15.2

USDA Yield GradeStep 3- % Kidney, Pelvic and Heart

Fat

Base = 3.5% +/- .5%= +/- 0.1 YG

% KPH YG ADJ

5.0 +.3

4.5 +.2

4.0 +.1

3.5 0.0

3.0 -.1

2.5 -.2

2.0 -.3

1.5 -.4

1.0 -.5

0.5 -.6

USDA Yield Grade Calculation

• Fat thickness = 0.5 in PYG=3.25 ≈ 3.3• HCW = 750 lb- Req. REA- 12.8• Actual REA- 14.1• 12.8 – 14.1 = -.433 = Adj Factor= -.4 3• 2.5% KPH= -.2• Final YG= 2.7

– For this class, all yield grades are calculated to the nearest 0.1 yield grade (range: 1.0-5.9) with no rounding

USDA Yield Grade• Next- Next-

We Will Use the 4-Step Method to determine USDA Yield Grade

• Again, 4 parameters utilized in beef yield grades

– HCW– REA– Adj. Fat Thickness– % KPH-Main difference between 3 and 4-step method

is in the 4-step method HCW and REA are not combined, accounting for the extra step.

USDA Yield Grade

Step 1- Determine Preliminary YG (PYG)

PYG= 2.0 + 0.25 YG for every 0.1” of fat

NOTE: Report all PYG to the nearest tenth of a PYG- round up

Example- 0.3”= PYG- 2.75

2.75= 2.8

Fat Thickness PYG

0.0 2.0

0.1 2.25

0.2 2.5

0.3 2.75

0.4 3.0

0.5 3.25

0.6 3.5

0.7 3.75

0.8 4.0

0.9 4.25

1.0 4.5

1.1 4.75

1.2 5.0

USDA Yield GradeStep 2- Determine weight

adjustment adjustment-Starts with a base of

600lbs and every increase in 25lbs is an increase in adjustment of 0.1

-Round on the 13-Ex- a carcass that weighs

762lbs needs to be adjusted +0.6, but a carcass that weighs 763lbs needs to be adjusted +0.7

Carcass Wt adjustment

550 -0.2

575 -0.1

600 0

625 +0.1

650 +0.2

675 +0.3

700 +0.4

725 +0.5

750 +0.6

775 +0.7

800 +0.8

825 +0.9

850 +1.0

875 +1.1

900 +1.2

925 +1.3

950 +1.4

USDA Yield GradeStep 3- Determine ribeye

(REA) adjustment adjustment

-Starts with a base of 11 square inches, and every increase in 1inch is an increase in adjustment of 0.3

-Easiest to call ribeyes on a “3-7-0” system. (all ribeyes end in .3, .7 or .0 as seen in the chart ---------------------------_

Ribeye area adjustment

10.7 +0.1

11.0 0

11.3 -.01

11.7 -0.2

12.0 -0.3

12.3 -0.4

12.7 -0.5

13.0 -0.6

13.3 -0.7

13.7 -0.8

14.0 -0.9

14.3 -1.0

14.7 -1.1

15.0 -1.2

15.3 -1.3

15.7 -1.4

16.0 -1.5

USDA Yield GradeStep 4- % Kidney, Pelvic and Heart

Fat

Base = 3.5% +/- .5%= +/- 0.1 YG

% KPH YG ADJ

5.0 +.3

4.5 +.2

4.0 +.1

3.5 0.0

3.0 -.1

2.5 -.2

2.0 -.3

1.5 -.4

1.0 -.5

0.5 -.6

USDA Yield Grade Calculation

• Fat thickness = 0.5 in PYG=3.25 ≈ 3.3• HCW = 750 lb- +0.6• REA- 14.1• 14.1-11.0=3.1X0.3=-0.9• 2.5% KPH= -.2• Final YG= 2.8

– For this class, all yield grades are calculated to the nearest 0.1 yield grade (range: 1.0-5.9) with no rounding