This study was conducted using 103 male and female lambs from the following genetic groups: Santa Inês (SS) purebred and Santa Inês × Texel (TS), Santa Inês × Ile de France (FS), and Santa Inês × Bergamacia (BS) crossbred. The animals were slaughtered at the following body weights: 15, 25, 35 or 45 kg. After slaughter and cooling of the carcasses, the following cuts were made: neck, rib/flank, short ribs, loin, blade, and hind limb. The composition in muscle, bone and fat of cuts and ½ carcass were evaluated. The alometric growth of each tissue of the loin, shoulder and leg in relation to the cut weight, and of each tissue of the ½ carcass in relation to the cold carcass weight, was measured. The allometric growth of muscles in the ½ carcass, for BS males and FS and BS females, was early (b<1). The alometric growth of the bone in the cuts and ½ carcass was early (b<1), except for shoulder bone in SS, TS and BS males, and TS females; and leg bone in BS males, with isogonic allometric growth (b=1). The development of fat in the cuts, and ½ carcass was late (b>1), except shoulder fat in BS males, with isogonic growth (b=1). The growth rate of shoulder muscles in SS and FS males, SS and TS females was isogonic (b=1); for TS and BS males, FS and BS females, it was early (b<1). The muscle development in the loin from SS, FS and BS males, and females FS, was isogonic (b=1); for TS males and SS, TS and BS females, it was negative heterogonic (b<1). The allometric growth of the muscle in the loin from SS, TS and FS, and SS and TS females, was isogonic (b=1); and for BS males and TS and BS females, it was negative heterogonic (b<1).
crossbreeding; development; growth; sheep
