This article has a double purpose. First, it intends to give a detailed study of the practices during the 18th century, in relation with managing the reproduction of the migrating cattle. The knowledge of these practices is essential to understand how the cattlemen could adjust the volume and quality of their wool production, and therefore the size and make up of their cabins, according to the fluctuations of the wool demand and the conditions of the pasture markets. Secondly, it intends to propose a reconsideration of the importance that the abandonment of these practices had in the unleashing and outcome of the profound crisis that affected the Castilian transhumance at the end of the first third in the 19th century.