Carcass Grading & Evaluation 02/11/25

  • Grading: to arrange or classify by grades; to rate according to quality, rank, worth, etc.; to sort

    • Grading sort carcass within sex classes (classed by gender and maturity) based on relative value

    • value for each livestock species depends

      • ex; age of sheep

    • Grades are designated to group livestock of similar market desirability based on predictions of the kind of carcass they will produce

  • Livestock are heterogenous: sex, maturity/age, fatness, muscling

    • Goal of a meat scientists to to turn heterogenous livestock into homogenous carcass groups

  • Sex

    • how do sexes differ?

      • dressing percentage, carcass proportions, cutability, palatability, acceptability

  • Age

    • as an animal increases in age, collagen starts to form cross links; meaning the meat is tougher and more flavorful

      • the older a lamb is, the more off flavors there are

        • ex: liver has an off flavor; it is an acquired taste

    • as age increases the meat becomes darker in lean color, yellow in fat color, diseased, and fatter

    • Beef

      • puberty at 12 months, market at 18 months

      • There are 5 maturity groups for beef: A, B, B50, C, D, E, E90

    • Swine

      • puberty at 7 months, market at 7 months

    • Sheep

      • puberty at 8 months, market “spring lambs” at 8 months, “old crop” lambs at 14 months or older

  • Two types of grades:

    • grades predict palatability; Quality grades

      • palatability = tender ness, juiciness, flavor of cooked meat products

    • Grades which predict cutability

      • aka yield grades

  • Two systems for palatability estimation:

    • bipartite or dichotomous; acceptable or unacceptable quality

    • Hierarchy; poor, average, good, better, best

  • Beef is boneless, closely trimmed retail cuts from the round, loin, rib, and chuck for beef

  • Bone in, skin on , closely trimmed four lean cuts (ham, loin, boston butt, picnic shoulder) for pork

  • Semi boneless, closely trimmed retail cuts from the leg, loin, rack, and shoulder for lamb

  • Weight

    • as an animal increases in weight, carcasses become fatter and retail cuts become larger

  • Meat Grading Services

    • Duties

      • application of quality and yield grades

      • acceptance — certification of fabricated products or brands

    • Administration

      • US Department of Agriculture

    • Grading vs. Inspection

      • both grading and inspection are USDA programs

        • meat inspection is administered by the USDA Food Safety Inspection System

      • ALL meat that is sold MUST, by law, be inspected but meat GRADING is OPTIONAL

    • Meat inspection is funded through tax dollars

    • Animals and carcasses MUST pass inspection BEFORE they can be graded

  • Custom Exemption

  • Farmer’s Exemption: an inspector does not have to be present if a farmer is harvesting meat for themselves

  • Lamb

    • Sex Classes

      • ewe, wether, ram, stag

    • Lamb Quality Grades:

      • prime, choice, good, utility, cull

    • Lamb Yield Grade: 1-5

    • 96% of market lambs rank choice or prime

  • Swine

    • Swine Sex Classes

      • the only livestock required to put “US”

      • USDA Pork Carcass Grades

      • Pork carcass grades

  • Bovine

    • Sex classes:

    • Beef Grades

    • Beef Yield Grade

  • Camera assisted grading