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 Determination Steer 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 Grades Based on consideration of two general factors: Physiological Maturity Skeletal Maturity Lean Maturity Marbling (Intramuscular Fat) Amount Distribution

USDA Beef Grades Maturity Scores: Marbling scores: (Highest to lowest) USDA maturity and marbling scores Marbling scores: (Highest to lowest) -Abundant -Moderately Abundant -Slightly Abundant -Moderate -Modest -Small -Slight -Practically Devoid -Devoid Maturity Scores: A Youngest B C D E Oldest

Relationship between tenderness and USDA maturity scores

Physiological Maturity vs Chronological Maturity The physiological maturity of the carcass is an estimate of the actual chronological age of the animal USDA 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 Maturity C00 35% 42 – 72 D00 70% 72 – 96 E00 90% E100 100% % Thoracic Ossification Approximate Age (Months) > 96 Skeletal Maturity: A00 B00 C00 D00 E00

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” Maturity “B” Maturity

A B C D E SACRAL DISTINCT SEPARATION LUMBAR NO OSSIFICATION THORAIC

Physiological Maturity of Lumbar Vertebrae of from carcasses with A40 and A50 Overall Maturity Scores A40 A50

A B C D E SACRAL LUMBAR THORAIC DISTINCT SEPARATION FUSED NO OSSIFICATION NEARLY COMPLETELY OSSIFIED THORAIC SOME PARTIAL CONSID. OSS. OUTLINES PLAINLY VISIBLE BARELY

A B C D E RIBS TEXTURE COLOR OF LEAN LIGHT RED SLIGHT TENDENCY TOWARDS FLATNESS SLIGHTLY WIDE AND FLAT TEXTURE FINE TENDS TO BE FINE SLIGHTLY COARSE MOD. COARSE COLOR OF LEAN LIGHT RED DARK RED

Skeletal Maturity A B C D E Sacral Lumbar Thoracic* Distinct separation Some separation Fused Lumbar No ossification Partial ossification Mostly ossified Ossified Thoracic* 0-10% 10-35% 35-70% 70-90% 90% + *Average ossification of first three thoracic vertebra

Spinous process of the Thoracic vertebra “Buttons” Thoracic vertebra

Beef Quality Grades- Lean Maturity Young Intermediate Mature A00 B00 C00 D00 E00

Various Maturity of Beef Cattle A-Maturity C-Maturity D-Maturity

Overall USDA Maturity A-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 Slightly Abundant00 Moderately Abundant00

USDA Quality Grades

Quality Grade

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 SM SL TR PD

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% 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 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

USDA Yield Grade 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) 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 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

USDA Yield Grade 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 Step 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

USDA Yield Grade 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 Step 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

USDA Yield Grade Step 2- Example 717 lb carcass needs 12.4 in REA 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 Step 2- Example 717 lb carcass needs 12.4 in REA Actual REA- 15.3 12.4 – 15.3 = .966 3 Adj Factor= -1.0

USDA Yield Grade Step 3- % Kidney, Pelvic and Heart Fat % 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 Step 3- % Kidney, Pelvic and Heart Fat Base = 3.5% +/- .5%= +/- 0.1 YG

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- 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) 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 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

USDA Yield Grade Step 2- Determine weight adjustment adjustment Carcass Wt adjustment 550 -0.2 575 -0.1 600 625 +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 Step 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

USDA Yield Grade Step 3- Determine ribeye (REA) adjustment adjustment Ribeye area adjustment 10.7 +0.1 11.0 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 Step 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 ---------------------------_

USDA Yield Grade Step 4- % Kidney, Pelvic and Heart Fat % 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 Step 4- % Kidney, Pelvic and Heart Fat Base = 3.5% +/- .5%= +/- 0.1 YG

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