Lamb Carcass Grading

USDA’s Dual Grading System

Yield Grade

1, 2, 3, 4, 5

expected yield of closely-trimmed cuts from the

leg, loin, rack, and shoulder (80% of the

weight and 90% of the value

Quality Grade

Prime, Choice, Good, Utility, Cull

predicts expected palatability (tenderness,

juiciness, flavor)

Determination of Class and Kind

Kind – Maturity

1. Lamb (A/B)

P,C,G,U,C / 1 - 5 2 – 14 month at least one perfect break joint slightly dark, pink flank round / red ribs

Class – Ewe, Wether, Ram1. Udder (smooth) or cod fat (rough)2. Conformation

2. Yearling muttonP,C,G,U / 1 – 5

12 – 25 month spool or imperfect break joints slightly to mod., dk. red flank mod wide / flat/ reddish ribs

3. MuttonP,C,G,U / 1 – 5

> 24 months spool joints dark to very dk. red flank wide, flat, white ribs

Break joint versus Spool joint

USDA Yield Grade

Purpose to segregate carcasses into cutablity groups based on the expected yield of closely-trimmed cuts from the leg, loin, rack, and shoulder (80% of the weight and 90% of the value

Expected YieldsYG 1 – 49.8% or more

YG 2 – 49.7% - 48.6%

YG 3 – 48.4% - 47.3%

YG 4 – 47.1% - 46.0%

YG 5 – 45.8% or less

USDA Yield Grade

USDA YG = (10 x 12th rib fat) + 0.4

USDA Yield Grades – 1, 2, 3, 4, 5- Avg yield grade of US lamb carcasses is upper 3

USDA Quality Grade• Predicts the eating quality of cooked lamb

cuts from the Shoulder, Rack, Loin, and Leg– (Prime +,◦,-; Choice +,◦,-; Good +,◦,-; Utility, Cull)

– 90+% of U.S. lamb carcasses grade Pr or Ch

• Based on:–Maturity (lamb, yearling mutton, mutton)

–Flank streaking (Traces, Slight, Small, Modest, etc.)

–Conformation (Prime +,◦,-; Choice +,◦,-; Good +,◦,-)

–Flank and fat firmness

–Minimum fat thickness

Flank Streaking Classes

Carcass Conformation

Pr° Pr- Ch° Ch- Gd+

Preliminary Quality Grade Adjustments for Conformation

1. Must have minimum Prime PQG for Prime grade.

2. In P & Ch, superior PQG can compensate for inferior conf. on an equal basis.

3. In Choice, superior conf. can compensate for inferior PQG on an equal basis for 1/3 grade.

4. In Good, PQG and conformation can compensate for each other on an equal basis for 1/3 grade.

Criteria for Placing Lamb Carcasses

1. Trimness / Fatness

2. Muscling

3. Dimension / Weight

Minimum Quality – Prime and Choice