Simulation results of closed MOET schemes have evidenced several problems issuing from selection in small populations using family information and diverse modifications of the original schemes have been proposed. Mate selection, based on linear programming techniques, includes most of the desirable properties of other methods and offers additional advantages. Some applications of this technique to improve the results of dairy cattle MOET schemes with hierarchical and factorial mating systems have been analysed in this note by computer simulation. Other applications of the method are also discussed.