Аннотация
Abstract Today in Uzbekistan it is important to strengthen the breeding base of cattle, increase the fertility and productivity of cattle. One of the main methods is purebred breeding breeds and crossbreeding with regionalized cattle breeds. Fertilization of Holstein breeds in hot climates, the formation of productive genetic potential of cattle of different genotypes, and the interaction of genotype-environment have not been sufficiently studied. Group I received 20% bloody holstin and 80% bloody simmental cattle obtained by crossing Simmantal cattle with red-and-Holstein breed. In groups II and III purebred phlegfix simmental-red-ola simmental cattle were selected. The cattle in this experiment were cared for in the storage and feeding conditions of the farm in the mountains.