The sequences of maturation and the precocity of the lambs of the Galician breed in two stages of growth (suckling lamb and “ternasco”) were studied, to know the rate formation of weaves and its influence on commercial pieces quality. In the results a greater proportion of muscle and bone is appraised in the suckling lamb and in ternasco of fats, specially the subcutaneous and the intermuscular one. The muscular weave of the suckling lamb shows a tendency of back to previous growth, from hind ribs to the foreribs, happening to have in ternasco a growth with previos to back tendency. In which one talks about the bony weave, trunk mature more delayed, whereas the low members and breast-brisket mature before, being increased the speed of growth of this weave with respect to the foreribs, that is the piece of more delayed bony development. The suckling lamb fat in leg piece has precocious maturation and the tail has it delayed, being isometric for the rest of the pieces whereas ternasco these tendencies transform into an early maturation for the foreribs and the tail.