Lamb Carcass Grading

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Lamb Carcass Grading
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USDAs 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)

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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
• P,C,G,U / 1 5
• gt 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

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Break joint versus Spool joint
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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

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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

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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

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Flank Streaking Classes
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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.

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Criteria for Placing Lamb Carcasses

• 1. Trimness / Fatness
• 2. Muscling
• 3. Dimension / Weight
• Minimum Quality Prime and Choice

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