Association of Coenzyme Q9 (COQ9) Gene Polymorphism with Traits of Reproductive Qualities of Holstein Cows.

The paper presents the results from 2019–2022 of studying the associations of polymorphism of the coenzyme Q9 (COQ9) gene, which affects the energy and metabolic processes in the body, with traits of the reproductive qualities of Holstein heifers. The experimental population was selected from animal analogues (251 heads). DNA testing of allelic polymorphism G → A (guanine → adenine) of the COQ9 gene, which results in changes in oxidative phosphorylation, that affects the respiratory function of mitochondria, was carried out by PCR-RFLP. Two alleles (A, 0.604; G, 0.396) and three genotypes (AA, 36.6%; AG, 48.2%; GG, 15.5%) have been identified in the COQ9–BstMB I gene locus, which indicates genetic biodiversity populations. The chi-square takes on a value well below the critical value (0.05). The population is in genetic equilibrium according to the Hardy-Weinberg law. The traits of the reproductive ability of cows (251 animals) of different genetic groups of the COQ9 gene have been studied. An analysis of the relationship between fertility rates and genotypes of the COQ9 gene showed that individuals with the COQ9AA genotype were characterized by increased live weight during insemination and at calving. Animals with the COQ9AG genotype were characterized by a later age of the first fruitful insemination, while the number of sperm doses spent on them was minimal. The same group of heifers had the shortest calving interval, open day and service period and, as a result, a greater yield of live calves, a high fertility index of Dohi and a reproductive ability coefficient. The data presented in our research prove the influence of genetic factors on the reproductive qualities of cattle, which makes it possible to develop systems for managing the productivity of farm animals based on the use of molecular genetics methods. [ABSTRACT FROM AUTHOR]