In this paper, the family size in a progeny test under limited testing facilities was determined considering a scheme where several commercial companies were competing. Companies that determined the family size in order to maximize the expected proportion of sires which will be selected from its stock were considered as competitive. On the other hand, companies that determined the family size in order to maximize he expected genetic progress were considered as altruist. Under the theory of games framework, it is shown that competitive companies obtain better commercial results than altruist companies. When competing against competitive companies, altruist companies obtained worse commercial results than they expect. When all companies were competitive, they obtained the same commercial results as if all of them were altruist, but the total genetic progress decreased. A numerical procedure is described to calculate the optimum family size to optimize the commercial results.
The result of this algorithm showed that this commercial equilibrium only depends on the heritability and the ratio between the total testing facilities of the population and the number of sires required for the market. This commercial equilibrium did not depend on the number of companies nor the size of each company.