In temperate Europe, sheep predominantly mate in autumn and lamb in the spring. In contrast, present-day Mediterranean husbandries practice autumn lambing, with benefits in terms of natural resource use and seasonal availability of animal products. Autumnal lambing is enabled by the conjunction of a capability of some Mediterranean breeds for "out-of-season " breeding, intentional scheduling by the herder, and autumnal rains providing forage resources for lactation. Autumn and winter sheep births have been demonstrated at Neolithic sites in the western Mediterranean. More works are needed to define the conditions leading to their emergence. This line of research uses oxygen isotope analysis in sheep teeth and involves modern references to define birth season. The existing references were biased in favor of winter and spring births. In this study, we enlarge them with 30 additional teeth from Lacaune and Merino sheep, including mainly summer and autumn births. Experiments were also conducted on Lacaune ewes, to address theoretical grounds on the implementation of autumn births: it implies to preserve females from conceptions by separating the sexes in autumn and re-introducing the rams among females in the spring. This second step also produces a "male effect. " We show that in the Lacaune breed, the proportion of spontaneously cyclic ewes in the spring is low in the absence of males and remains minor when the ewes are left in permanent contact with rams. On the other hand, we were able to implement a highly efficient male effect using non-sexually stimulated males, demonstrating that this practice could have been implemented by Neolithic herders.