The most important biological factors, mainly determining the economic efficiency of milk production, are the productivity potential and the level of viability of cows. The aim of the work is to predict the bio-economic effects in a heterogeneous population of dairy cows taking into account the decrease in the length of productive life with increase in milk productivity. In the considered model situation, with an increase in the productivity of cows, the total profit per cow per year increases, while the profitability of production may decline. The developed algorithms are supposed to be used for solving the problems of optimizing the management of the dairy cow herd and planning technological development in animal husbandry.