YIELD OF TRIMMED PORK PRODUCT IN RELATION TO WEIGHT AND BACKFAT THICKNESS OF THE CARCASS

Abstract

Yield of commercially trimmed (CT), boned (B) and boned-defatted (BDF) pork in relation to weight and backfat thickness was evaluated from a sample of 3807 carcasses obtained from the kill lines of three commercial packing plants located in the provinces of Alberta, Ontario and Quebec. Sampling procedures at each plant were designed to provide carcasses from 10 males and 10 females in each cell of a grid defined by 10 weight classes (5-kg intervals ranging from 60 to 100 kg) and 13 fat classes (5-mm intervals ranging from 35 to 90 mm). Fat classes were determined on the basis of the sum of two measurements made at the points of minimum back and maximum loin. Fat class was the primary determinant of yield from the individual lean cuts (ham, loin, picnic and butt) with yield of CT, B and BDF product decreasing as fat class increased. Carcass weight had a negligible influence on yield after fat was considered and the effect associated with region and sex, while statistically significant, were also negligible. These results indicated that a single regression equation based on fat class would suffice for purposes of yield grading of Canadian hog carcasses. This equation identified a change in percentage yield of the combined lean cuts of 0.89% per fat class (5 mm of fat) with this relationship stable over the carcass weight range of 55–105 kg. Percentage yield of CT product from the total carcass (lean cuts plus belly) was less responsive to changes in total fat (0.50%) because belly yield, both untrimmed and trimmed, increased with increasing fatness.