Abstract
<jats:p>It was found that at all ages, crossbred animals outperformed purebreds in all studied parameters. Moreover, the second generation crossbreeds of all experimental groups were distinguished by the highest live weight, absolute and average daily gain, and relative growth rate. It is sufficient to note that purebred Kazakh White-Headed bulls were inferior to the crossbred bulls of groups II and III in live weight at one year of age by 14.5 kg (4.4%, P < 0.001) and 9.6 kg (2.9%, P < 0.01), respectively, purebred heifers by 23.8 kg (9.4%, P < 0.001) and 13.4 kg (5.3%, P < 0.01), purebred castrated bulls by 20.7 kg (6.6%, P < 0.01) and 14.3 kg (4.5%, P < 0.01) at 15 months. – by 21.4 kg (5.1%, P<0.001) and 10.9 kg (2.6%, P<0.01), by – 26.8 kg (8.6% P<0.01) and 15.3 kg (9.9%, P<0.01), by – 25.7 kg (6.6% P <0.001) and 17.1 kg (4.4%, P < 0.01), at 18 months. – by 27.2 kg (5.5%, P<0.001) and 14.1 kg (2.8%, P<0.01), by. – 35.2 kg (9.9%, P < 0.01) and 19.8 kg (5.6%, P < 0.01), by – 30.9 kg (6.7%, P < 0.001) and 20.7 kg (4.4%, P < 0.001), respectively. The obtained data indicate that the degree of manifestation of the effect of crossing the crossbred animals of group II (½ Hereford x ½ Kazakh White-Headed) is higher than that of their crossbred peers of group III (¾ Kazakh White-Headed x 1/4 Hereford), which is confirmed by the higher live weight of young animals of group II in all periods of the postnatal period of ontogenesis.</jats:p>