Lamb Carcass Grading USDAs Dual Grading System Yield Grade 1, 2, 3, 4, 5 expected yield of closelytrimmed 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 Class Ewe, Wether, Ram 1. Udder (smooth) or cod fat (rough) 2. Conformation
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 2. 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 P,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 closelytrimmed 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% - 48.6% YG 3 48.4% - 47.3% YG 4 47.1% - 46.0%
YG 5 45.8% or less 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 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
