Distribution and Composition of Porcine Carcass Fat

Abstract

Data were obtained from 616 hog carcasses from seven lines of breeding. Boars were leaner and barrows fatter than gilts on the basis of subcutaneous, body cavity, intermuscular and intramuscular fat. There were some sex differences in distribution of fat with gilts having substantially less inter- and intramuscular fat of loin than either barrows or boars. Boars reached market weight (90 kg) 12 days earlier than barrows and 10 days earlier than gilts. Significant line effects were detected for all measures of fatness except intramuscular fat determinations. Significant line effects were apparent also for percentages of various fatty acids. However there were no line differences in relative distribution of fat among the four fat depots examined and there were no sex-line interactions. Degree of fatness was directly related to degree of saturation of the constituent fatty acids. Fatter carcasses had higher values for percent myristic and palmitic acids and a lower percentage of linoleic acid. Boars and barrows had higher percent linoleic acid than gilts, while barrows had greater percentage of the saturated myristic and palmitic acids than gilts or boars. These differences were reflected in differences in iodine values. Phenotypic correlations indicated no conclusive relationship between rate of gain and degree of saturation of the fatty acids. Backfat measurements provided a reliable measure of total fat trim whether on an absolute or percentage basis. However, the associations between body cavity fat and trimmable fat though positive were not close. Intramuscular fat determinations were highly related to each other but unrelated to other fat depots.