Prediction of Fat and Fat Free Live Weight in Broiler Chickens Using Backskin Fat, Abdominal Fat, and Live Body Weight

Abstract

Data from 100 male and 100 female broiler chickens that were raised on the floor under two lighting regimes (12 and 24 hr light) were combined. Birds were weighed when 58 days old (male data presented first) (2372 g, 1913 g) and then slaughtered at 59 days. Abdominal fat was weighed (2.18%, 2.82%) and fat extracted from ground carcass (12.0%, 13.7% wet basis), intestines (47.6%, 56.2% dry basis), and from a triangular section of backskin (86.1%, 88.0% dry basis). Percent total fat was 10.4 and 12.2 (wet basis). Abdominal fat regressed on live body weight produced negative intercepts, indicating that regressed rather than percent values should be used.Fat from the four locations mentioned above had correlation coefficients of +.45 to +.76 for males and +.47 to +.74 for females. Percent abdominal fat had low nonsignificant correlations with fat free live body weight (r = +.23 male, −.07 female). Abdominal fat weight was a better (higher r2) predictor of total fat, total fat minus abdominal fat, percent carcass fat, and percent intestinal fat, than percent backskin fat. Thirty-three percent (male) and 22% (female) of the variation of percent abdominal fat was accounted for by percent backskin fat. Abdominal fat should be obtained directly and used for predicting fat in the bird rather than backskin fat.Abdominal fat was +20.7% (male) and +22.8% (female) of total fat. Prediction equations for estimating total fat and fat free live weight, given abdominal fat, and live body weight were developed.Selection against percent abdominal fat would probably result in a reduction of fat in other locations and little change in fat free live weight.