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 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

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 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 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.

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