Carcass Evaluation and Meat Grading Systems

Carcass Evaluation

• Carcass evaluation focuses on yield, processing, palatability, and overall quality, providing a more detailed analysis than simple grading.
• Dressing percent is calculated by dividing chilled carcass weight by live weight and multiplying by 100.
  • Cattle: 50-54%
  • Sheep and Goat: 35-50%
  • Veal: 63%
  • Pig: 65-70%
• Carcass length is measured from the first rib to the aitch bone, but has little impact on lean yield.
• Average back fat thickness is measured at three points: first rib, last rib, and last lumbar vertebra.
• Ribbing involves sawing through the 10th and 11th thoracic vertebrae to assess the rib eye area (LEA).
• Loin Eye Area (LEA) is a measure of muscle development, specifically the longissimus dorsi muscle between the 12th-13th ribs (ruminants) or the 10th-11th ribs (pork).
• Fat depth is measured at the 3/4 point over the rib eye using a probe graduated in 1/10 cm increments.

Meat Grading Systems

• Carcass grading divides meat into categories based on traits like palatability, yield, and quality.
• Grading Specifications for Mutton:
  • Prime Grade: Well-fleshed, even fat distribution, from wethers or ewes (fat-tailed types excluded).
  • Grade 1: Fair finish, reasonably fleshed, from wethers or ewes (moderately over-fat carcasses allowed).
  • Grade 2: Either fair finish and poorly fleshed or reasonably fleshed and poor finish, from wethers or ewes or rams of better carcass quality (moderately over-fat carcasses allowed).
  • Grade 3: Does not meet requirements of other grades.
• Grading Specifications for Lamb:
  • Super Grade: Proper finish, well-fleshed, good quality, from wether or ewe lambs or ram lambs with little masculine character (even fat distribution, fat-tailed types excluded).
  • Grade 1: Fair finish, reasonably fleshed, from wether or ewe lambs or ram lambs with no marked masculine character (moderately over-fat carcasses allowed).
  • Grade 2: Either fair finish and poorly fleshed or reasonably fleshed and poor finish, from wether, ewe or ram lambs (moderately over-fat carcasses allowed).
  • Grade 3: Does not meet requirements of other grades.
• Grading Specifications for Chevon:
  • Class A Super Grade: Proper finish, reasonably well-fleshed, from goat ewes with no permanent incisors.
  • Class A Grade 1: Fair finish, reasonably fleshed, from goat castrates and does with not more than two permanent incisors.
  • Class A Grade 3: Does not meet requirements of other grades.
  • Class B Grade 1: Proper finish, reasonably well-fleshed, from goat castrates and does.
  • Class B Grade 2: Fair finish, reasonably fleshed, from goat castrates and does (over-fat but not grossly over-fat carcasses allowed).
  • Class B Grade 3: Does not meet requirements of other grades.
• Appeals against grading: Owners or their agents can appeal grading decisions to the Director, provided they inform the meat grader before removing the carcass.

South African Meat Grading System

• Purpose: Ensures quality meat production, indicating age and fat content.
• Carcass Markings:
  • Age: Indicated by a row of three letters (AAA, AB, B, C), with purple for lamb, green for AB, brown for B, and red for C.
  • Fat Content: Indicated by a triple number (222, etc.) with 0 being no fat and 6 being excessively overfat.
  • Conformation: Indicated by a 1, 2, or 3, with 3 indicating a medium carcass.

USDA and BIS Grades

• USDA Beef Quality Grades: A system used for grading beef carcasses.
• BIS Grades for Meat:
  • Beef and Buffalo: Six grades based on conformation, finish, and quality (IS 2537).
  • Sheep and Goat: Divided into main classes primarily based on age (IS 2536: 1995).