In domestic livestock production, one of the most complex sectors livestock is dairy cattle breeding. Milk yields >10,000 kg/year are common in modern dairy production, owing to improved nutrition, management, and genetic gains through the use of progeny-tested bulls. However, reproductive performance has decreased worldwide in many cows with a high genetic potential for milk production, particularly in the Holstein breed. the production of milk has been observed in the Al-hiera project in Libya through the importation of highly productive pedigree dairy cattle from abroad. Everywhere, old farms are being reconstructed, new complexes are being constructed that are not inferior to the dairy equipment of foreign level. The intensive technology of dairy cattle breeding is a complex of highly effective methods of breeding, feeding, keeping and using animals, ensuring their high productivity, labor productivity, production culture and product quality. Central to the introduction of intensive technologies is breeding work, the goal of which is to search for the most valuable heredity potential. The article shows that there are no significant differences between the experimental groups with age and those differences that were found to be statistically not authentic. The superiority in the milk productivity of cows obtained from the "refreshment" of blood in the third lactation over the local dildos did not affect their reproductive ability. This is evident from the service period in cows in the third lactation, which is 52 days in the control group and 63 days in the control group cows.