Calving seasonality at Pool, Orkney during the first millennium AD : an investigation using intra-tooth isotope ratio analysis of cattle molar enamel.

摘要

The identification of dairying is essential if we are to understand economies of the past, particularly inudnorthwest Europe, where a high degree of lactose tolerance suggests that fresh milk has long been audsignificant food product. This paper explores a possible link between economic focus and seasonality ofudcalving. Although cattle (Bos taurus) can breed throughout the year, animals living in temperate regionsudwith minimal or no human management tend to breed seasonally, their breeding behaviour being stronglyudinfluenced by the availability of food. In order to achieve a year-round supply of fresh milk in the past, it isudlikely that multiple-season calving was necessary, which would have required additional husbandry effort.udAlternatively, for meat-focussed economies or those based on storable dairy products, a strategy ofudsingle-season calving in spring may have been favoured to maximise the utilisation of spring and summerudvegetation. Cattle birth seasonality is investigated through isotope ratio analysis (δ18O, δ13C) of toothudenamel. Results for cattle from Pool, Orkney dating to the latter part of the first millennium AD suggest thatudcalving occurred during at least three seasons implying that the continuous provision of fresh milk was ofudeconomic importance.