Sažetak The crucial problem in managing the dairy herd renewal processes, as well as its size, is the optimizing the timeframe of economic use of animals, depending on the prospects for the development of production and market conditions. The aim of the study was to evaluate and improve methods for calculating the optimal duration of economic use of dairy cows. Models with and without taking into account stochastic characteristics of the studied process were used for the analysis. The results of the survey conducted in 2018-2019 in LLP "Olzha- Sadchikovskoe" located in the northern part of Kazakhstan were used as initial data. It is noted that the greatest difficulties in solving the problem arise while optimizing the plan for renewing the existing herd at the expense of animals with high productive potential. This is explained mainly by the fact that animals of different productive ages have different economic value due to changes in their milk productivity with age with a certain regularity. The optimal duration of productive life of dairy cows with an average annual yield of 5,000 – 6,000 kg per head in the Northern Kazakhstan is about six years. It is noted that in Kazakhstan the widespread use of calculation methods with and without stochastic characteristics of dairy production is limited by the fact that in most agricultural enterprises there is no accounting of data relating to the patterns of change in the economic value of animals depending on their age, as well as probabilistic characteristics of milk productivity (cow mortality rate, infertility, etc.). The key issue in the development of an effective strategy of dairy herd management is the forecasting of price dynamics for milk and feed. In addition, in developing economies, including Kazakhstan, effective management of dairy herd renewal processes requires, first of all, the organization and implementation of management accounting system in animal husbandry.