Analysis of body composition changes of swine during growth and development

This study was conducted to model the growth of carcass, viscera, and empty body components and component composition of pigs. Quantitative tissue and chemical composition of 319 swine, representative of barrows and gilts fro m five commercial genetic populations, was determined at eight stages of gr owth between 25 and 152 kg, After whole body grinding and carcass dissectio n, proximate analyses were performed to calculate concentrations of protein , lipid, moisture, and ash of carcass, viscera, empty body, carcass lean, a nd carcass fat. Linear and nonlinear equations were developed to investigat e the growth patterns of each component. Nonlinear growth functions account ed for the greatest amount of variation in empty body protein, lipid, moist ure, and ash mass. Differences (P < .05) existed between barrows and gilts for nearly all components investigated. Carcass lean and fat tissues signif icantly increased in Lipid percentage and decreased in moisture percentage as live weight increased. There were significant changes in the ratio and c omposition of the tissues of barrows and gilts during growth. Nonlinear mod els fitted the data better than allometric equations for nearly all of the components investigated.