The aim of this study was to evaluate the correlation and to develop regression equations between the body composition obtained by the comparative slaughter and the neck composition and the ultrasound ribeye area (REAu) in goats from the Brazilian semiarid region. Forty-five intact male goats from three genetic groups were used: 15 Canindé, 15 Moxotó, and 15 F1 Boer x non-descript breed. Animals were randomly assigned to three feeding levels (ad libitum, 25 and 50% restriction) aimed to result in different slaughter weights and body composition, to fit the regression equations. The REAu was assessed between the 12th and 13th ribs with a 7.5 MHz linear transducer. The values of crude protein, ether extract, and water in the empty body showed high positive correlation (P < 0.01) with REAu and with the same values measured in the neck for all genetic groups. In addition, body composition was well predicted (R(2) > 0.80) from the REAu and from the neck composition.