(1) To translate the evaluation of age, weight, sex, fatness and muscling into readily usable market descriptions.
(2) To determine how and why grades of slaughter animals and carcasses are important to animal agriculture.
(3) To demonstrate the factors involved in quality and quantity evaluations of animals and carcasses.
Grades — Groups of livestock of similar market desirability in terms of predictions of the type of carcass they will provide.
Of these, weight and sex are easily described, but age, fatness and muscling have endless combinations.
It became obvious in the early 1920’s that some common terminology had to be developed to facilitate market news reporting and transactions sight unseen.
Grading concepts —> Once the purpose is defined, specific traits in carcasses can be used to identify and stratify carcasses into homogeneous groupings.
Hierarchical — several entities arranged in a graded series
Superior Good Average Inferior
Original concepts of beef carcass grading
Group for elite consumers where taste was the only issue Groups for retail consumers with different priorities for taste and leanness Groups for further processed (ground, comminuted or prepared beef items)
Thus, Prime was identified for the elite consumers, Choice, Select and Standard for retail consumers, and Commercial, Utility, Cutter and Canner for manufacturing beef.
Cutability grades were developed in the 1960’s as more accurate ways to segment carcasses based on the yield of closely trimmed, boneless retail cuts because it was possible to have very lean and very fat Choice carcasses. In the cutability systems for beef, pork and lamb, the following are important measures that are closely related to carcass composition:
|Muscling||Ribeye area||Muscling score||None|
|Trimmable fat||Fat thickness, 12th rib||Backfat, last rib||Fat thickness, 12th rib|
|Internal fat||Kidney, pelvic & heart fat||None||None|
Review of Material — What the student should know:
(1) The concepts of grades.
(2) Differences in dichotomous versus hierarchical grading.
(3) Why compositional grades were developed.