1. Lamb Carcass Grading

2. 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)

3. Determination of Class and Kind
Class – Ewe, Wether, Ram
1. Udder (smooth) or cod fat (rough)
2. Conformation
Yearling mutton
P,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. Mutton
> 24 months
spool joints
dark to very dk. red flank
wide, flat, white ribs
Kind – Maturity
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

4. Break joint versus Spool joint

5. 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 Yields
YG 1 – 49.8% or more
YG 2 – 49.7% %
YG 3 – 48.4% %
YG 4 – 47.1% %
YG 5 – 45.8% or less

6. USDA Yield Grade USDA Yield Grades – 1, 2, 3, 4, 5
- Avg yield grade of US lamb
carcasses is upper 3
USDA YG = (10 x 12th rib fat) + 0.4

7. 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

8. Flank Streaking Classes
Carcass Conformation
Pr° Pr Ch° Ch Gd+

10. Preliminary Quality Grade Adjustments for Conformation
Must have minimum Prime PQG for Prime grade.
In P & Ch, superior PQG can compensate for inferior conf. on an equal basis.
In Choice, superior conf. can compensate for inferior PQG on an equal basis for 1/3 grade.
In Good, PQG and conformation can compensate for each other on an equal basis for 1/3 grade.

11. Criteria for Placing Lamb Carcasses
1. Trimness / Fatness
2. Muscling
3. Dimension / Weight
Minimum Quality – Prime and Choice