the reproductive function is the most important factor in the system of economic cattle breeding. Productivity problems in Simmental cows were identified when analyzing the results of the previous studies. The factors influencing the decrease in cow’s reproductive capacity are shown. These factors are: differences in the animals’ genetic type, reproductive and unproductive diseases of cows, increased milk productivity of cows, as well as stress caused by such environmental factors as hypoxia, adinamia, insolation, feeding mode.