Carcass Composition Changes in Growing and Finishing Swine

Abstract
Thirty Yorkshire and seventy Hampshire barrows were slaughtered at five pre-determined weights (45.4, 68.2, 90.0, 113.6 and 136.4 kg) in an effort to characterize changes in composition with respect to muscle, fat and bone in heavily-muscled pigs. Standard carcass measurements were obtained and the right carcass half of each pig was separated into lean, fat and bone. The relationship between average backfat thickness and weight appeared to be linear in the Hampshire data, while a non-linear (P<.05) relationship was found in the Yorkshire data. Rather uniform increases in loin eye area and carcass length were observed from 68.2 to 136.4 kg in the Yorkshire data, while non-linear (P<.05) responses, more characteristic of the “Classical” growth curves for loin eye area and length, were found in the Hampshires. Linearlike trends were observed between kilogram of lean, fat and bone with slaughter weight in the Yorkshire data. The stage of greatest increase in lean composition occurred from 90.9 to 113.6 kg for both breeds. The relationships between kg of lean cuts, ham and loin, and ham with slaughter weight appeared to be linear in the Yorkshire data; however, non-linear (P<.05) responses for lean cuts and ham and loin were found in the Hampshires. A slight decrease in lean cuts, when expressed as a percentage of carcass weight, was found with increased weight for each breed; however, similar trends were not observed for ham and ham and loin yields. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.