On 677 cows of Holstein, Ukrainian black-and-white (UBaWDB) and Ukrainian red-and-white (URaWDB) dairy breeds, their reproductive ability and milk productivity were studied for the first (369 heads) and second (308 heads) lactation, depending on the age of fertilization of heifers. Heifers of breeding age, depending on the age of insemination and fertilization with a live weight of 360–380 kg, were divided into 3 groups: 12-14 months, 15-18 months and 19-22 months. In cows of the UBaWDB of the first group, the average duration of the service period (SP) for two lactations was 169 days, the lactation period (LP) – 373 days, milk yield per lactation – 10066 kg; the second group – 160 days, 365 days respectively and 9428 kg respectively; the third group – 169 days, 379 days and 9499 kg. The duration of the service period for cows with normal deliveries and the course of the postpartum period was mainly 100-120 days, and the milk productivity of Holstein cows was 8-10 thousand kg, UBaWDB – 8-9 thousand kg and URaWDB – 7-8 thousand kg. Experiments have shown the economic feasibility of effective rearing of heifers and their earlier insemination at the age of 14-18 months, and well developed ones – at the age of 12-13 months.