Indirect methods for predicting the body composition of sheep of different sex classes

Abstract

The aim was to evaluate the correlation and develop regression equations for the body composition of sheep of different sex classes, obtained by the comparative slaughter method, using the composition of the neck region and loin eye area (LEA). Forty-five sheep of three sex classes (15 intact males, 15 castrated males and 15 females) received three feeding levels ( ad libitum or restrictions of 70 or 80% of ad libitum intake). Animals were distributed in a 3×3 factorial arrangement, with 5 repetitions. The LEA showed: positive correlation with empty body weight, fasting body weight, meat, protein, ether extract and water (p < 0.01), for all sex classes; with bones for intact males and females (p < 0.01); with ash content for intact males and a moderate correlation for castrated males (p < 0.01). The neck was correlated with empty body weight, fasting body weight, meat, protein, ether extract, water and energy in all sex classes (p < 0.01); and moderate correlation with bone (r=0.58) and ash (r=0.67) for intact males. Intact males showed higher R² values in their prediction equations in relation to the other sex classes.