Pork Carcass Measurements and Their Relationship to the Amount of Lean and Fat

Abstract

Intact carcass measurements were taken from 60 pork carcasses (24 barrows, 36 gilts) that were trimmed into wholesale cuts and then physically separated into fat, lean and bone. Backfat measurements including average, first, third, sixth and last rib and last lumbar were correlated (P ◄ .01) with percentage fat, lean and bone. A single fat measurement at the sixth rib was as highly correlated (P ◄ .01) as average backfat with carcass fat, lean and bone content. This appears to be a simple measurement of great value to the industry. The best equation using intact carcass measurements to predict total fat employed seven variables which were chilled wt., seam fat, car. length, 3rd rib backfat, last rib backfat and depth of fat over the longissimus muscle at the 6th and 10th ribs (R 2 = .85). The best equation using the fabricated wholesale cut weights to predict total fat used eight variables (R 2 = .88). Equations to predict the weight of total lean were most reliable with seven variables (R 2 = .78). Regression equations to predict total lean weight and total fat weight using backfat alone gave R 2 values in the range of .15 to .20. The use of the factors utilized in many NPPC formulas (hot car. wt., LMA, 10 rib and depth fat, 10 rib) resulted in R 2 values of .65 to .75. A ranking of carcasses from best to worst should involve a more complicated formula than is normally utilized.