Evaluating the role of milk production in prehistoric subsistence economies requires a better estimation of the capacity of a milk-oriented husbandry under prehistoric conditions. Weaning pattern, which is linked to the length of lactation, is an important parameter in this estimation. In this study, weaning pattern is closely examined in Neolithic cattle from the site of Bercy (Paris, France, c.4000bc ), by a study of intra-tooth (M1, M2) variation in the nitrogen isotope ratios (δ¹⁵N) of dentine collagen. Collagen δ¹⁵N is commonly used to trace the change of trophic level at weaning time. The pattern of change in collagen δ¹⁵N in the first molar of two archaeological bovines is then compared with that observed in modern cattle weaned at known age. Results suggest that the Neolithic calves were weaned early. This could reflect either a shorter lactation for Neolithic cows, or early weaning imposed by the herder in order to reserve a bigger proportion of milk production for human consumption.