Lamb Carcass Grading USDAs Dual Grading System Yield

Lamb Carcass Grading

USDA’s 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 Ø Ø 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 Ø Ø 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 Ø Ø > 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 Grades – 1, 2, 3, 4, 5 - Avg yield grade of US lamb carcasses is upper 3 USDA YG = (10 x 12 th 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