Author

Daniel H. Gee

Document Type

Thesis - Open Access

Award Date

1970

Degree Name

Doctor of Philosophy (PhD)

Department

Animal Science

Abstract

Studies designed to investigate the accuracy of predicting total edible portion weight from a pork carcass were conducted over a two-year period. One hundred fifty crossbred pigs of prominent Hampshire-Yorkshire breeding weighting an average of 203.2 ± 5.1 pounds were used in this study. The pigs were 160.8 ± 11.0 days of age at slaughter, had an average of 1.39 inches of carcass backfat and 4.51 square inches of longissimus dorai area. The following measurements were collected in the cooler and used in an attempt to predict total pounds of edible portion: animal age at slaughter, weight off test, slaughter weight, carcass length, average carcass backfat, longissimus dorsi area and chilled carcass weight. In addition, head weight, viscera weight, leaf fat weight and several fat probe measurements were collected and used. Both the right and he left sides of each carcass backfat and longissimus dorsi area were -.42 (P<.01), -.62 (P<.01) and 0.58 (P<.01), respectively. The two fat thickness measurements taken between the 12th and 13th ribs at one-fourth and one-half the length of the longissimus dorsi muscle from the chine bone end showed high correlation coefficients with total edible portion weight (r= -.56 and -.56). The highest correlation coefficients between the various fat probes and pounds of edible portion were the probes taken in the area of the lumbar vertebrae (r=-.43 and -.48). Correlation coefficients between pounds of edible portion and animal age at slaughter, slaughter weight, carcass length and chilled carcass weight were -.15, 0.21 (P<.01), 0.21 (P<.01), respectively. Chilled carcass weight averaged 149.4 ± 4.1 pounds and the total fat weight from each carcass averaged 36.5 ± 5.0 pounds. Multiple regression analyses were made to provide prediction equations for estimating total pounds of edible portion and total fat weight. Among the equations to predict fat weight were (1) Y=6.41+1.61 (average carcass backfat thickness) + 1.32 (leaf fat weight) – 1.81(longissimus dorsi area) + 0.21(chilled carcass weight), R=.883 and (2) Y=36.26 + 1.68 (average carcass backfat thickness) + 1.29 (leaf fat weight) -1.47(longissimus dorsi area) -.09 (animal age at slaughter), R=.881 and (2) Y=-6.37-1.21(average carcass backfat thickness) + 0.61 (chilled carcass weight) + 2.01 (longissimus dorsi area), R=.869.

Library of Congress Subject Headings

Swine -- Marketing

Pork -- Grading

Format

application/pdf

Number of Pages

80

Publisher

South Dakota State University

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