A Comparison of Methods for Estimating Carcass and Empty Body Composition in Swine from Birth to 145 Kg

A study was conducted with 65 pigs to evaluate several methods for estimating carcass and empty body composition from 18 to 145 kg body wt. Carcass measurements, specific gravity and a method involving chemical analysis of the sawdust residue from sawing the carcass in cross sections at 2.54 cm intervals were evaluated. Prediction equations were derived from each of these measurements for estimation of carcass and empty body composition. The sawdust residue analysis procedure was the most accurate technique for prediction of carcass and empty body water, protein and fat. The ash component was not estimated accurately with any techniques evaluated. The relationship between specific gravity and carcass composition was highest in animals between 54 to 109 kg live wt. Of the several carcass measurements evaluated, backfat thickness was the best predictor of carcass composition, but was poorer than either the sawdust analysis technique or specific gravity. Carcass weight and composition were closely related to weight and composition of the empty body (ingesta-free). Consequently, prediction equations from carcass sawdust residue analysis estimated either carcass or empty body composition with approximately equal accuracy and were superior to prediction equations that used specific gravity or backfat thickness measurements.