A literature review of the high relevant and recent economic concepts related with selection in Dairy Cattle was carried out in the first part of the paper. The steps of an economic study of an animal breeding programme are the definition of an aggregated genotype related with the selection objectives, development of a profit equation that include incomes and cost of the production system, estimation of economic values of each trait included in the aggregated genotype and derivation of discount rate of each trait.
An example by using economic and yield data of dairy cattle herds from the Basque Country Autonomous Community and Alta Maraña Cooperative of Avila has been developed in the second part of the paper. Results show that the economic values on yield traits and longevity depend on the quota on production, level of production, milk prices and production cost. Quota on production reduce the weight on yield traits, mainly kg, of fat and kg of volume. Level of production and milk prices affect the economic value on yield traits. Economic value on longevity depends on percentage of culled cows and on the cost of rearing heifer.
It is concluded that the derivation of a selection index in dairy cattle should be done on specific production area.