Specific Gravity of the Carcass and of Its Parts As Predictors of Carcass Composition in Broiler Chickens

Abstract

Data from two strains of broiler cockerels reared either in floor pens or in individual cages were obtained to investigate the adequacy of specific gravity of the chilled carcass or of the individual carcass parts as predictors of broiler carcass composition. Relationships between carcass composition and specific gravity were generally linear. Except for the relationship between carcass composition and specific gravity of back, which was influenced by strain (P<.05), the relationships between carcass composition and specific gravity of chilled carcass or carcass parts were not influenced (P>.05) by strain or type of rearing. The addition of chilled carcass weight as a second variable generally resulted in a small but statistically significant reduction of the residual standard error of prediction. In terms of residual standard errors, the use of specific gravity of the individual carcass parts over specific gravity of the chilled carcass did not improve the accuracy of prediction. Due to relatively high residual standard error, it was concluded that specific gravity should be used to estimate compositional differences among sib or progeny groups of broiler carcasses rather than among individual carcasses.