Cattle (Bos taurus) are biologically able to breed year-round, potentially giving farmers the freedom to choose a calving strategy to best meet their economic goals. Thus, an accurate method to determine cattle birth seasonality from archaeological remains would prove to be a valuable tool when investigating a prehistoric farming community. This paper presents the results of intra-tooth isotope ratio analysis (δ18O, δ13C) of first, second and third molars from 15 cattle. The principal outcome is a possible new approach to determining cattle birth seasonality utilizing both carbon and oxygen isotope ratio measurements of first molar enamel. Although this technique requires verification through more extensive testing, particularly of modern material, initial results suggest that it may produce more accurate predictions of birth seasonality than techniques based on intra-tooth δ18O measurements of second and third molars.