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The experiments were carried out in herds with repeatedly barren animals after insemination to study the reproductive ability of cows under different keeping conditions. As a result, the efficiency of insemination of double-barren cows was higher in synchronised heat with gonadotropin and prostaglandin. It ranged from 48 to 70%, while the effect of exposure to drugs was higher in all cows with loose housing. After synchronisation of heat in cows with loose housing, with the introduction of surfagon before insemination, the fertilisation rate was 70%, ovulin - 63.3%, with control 46.6%, with tethered housing - 60; 63.3 and 33.3%, respectively. However, all groups must identify cows in the heat for at least 72 hours. Otherwise, it is predicted that the measures' effectiveness will decrease by 30% or more.

Increased productivity in the industry can be achieved by breeding for productive longevity through searching and using genetic markers. The study analysed the data of 1476 animals with at least one completed lactation. Depending on the linear affiliation and kappa-casein gene genotype of servicing bulls, their female offspring were divided into 4 groups. The CSN3 A allele frequency in the studied bulls was 81.91%, the CSN3 B allele was 18.09%. The highest frequency of the desired CSN3 B allele in the servicing bulls-producers of the Reflection Sovering line was 20.83%, which is 3.69% more than in the bulls of the Vis Back Ideal line. The animal life length analysis showed that the female progeny of bulls from the Reflection Sovering line (2.46 lactation), especially those with the CSN3 AB genotype (2.59 lactation), had the longest life. The offspring of CSN3AB genotype bulls of the Reflection Sovering line had the highest lifetime milk yield (18490 kg). The CSN3AB genotype cows of the Reflection Sovering line had the highest average milk yield on the 1st day of a cow’s life of 9.05 kg.