Since the foundation and the growth of the agricultural Common Market, the expansion of the dairy activities has occured differently for the members. This text tries to analyse, from the Rica 82 whereas the evolution come from the productive component and from the efficiency and shows how the production and the dairy farms'incomes are determined. On the other hand it développes how the monetary fluctuation among the european countries which induce relative prices differences, may involved more or less a support for the development of the dairy farms.