N.A. Popov
L.K. Ernst Federal Research Center for Animal Husbandry, pos. Dubrovitsy, 60, g.o. Podol’sk, Moskovskaya obl., 142132, Russian Federation
Abstract. The study determined the efficiency of improving milkiness traits at intraline selection and crosses of lines using bulls with different combinations of EAB-locus alleles in genotypes. When forming a highly productive herd of Red-Motley cattle, we used stud bulls of the Holstein breed with homo- and heterozygous genotypes of the EAB-locus. They were selected in lines and by the method of line crossing. When analyzing the offspring in the context of the genotypes of fathers and the types of their selections, we compared the groups of daughters according to the main characteristics of selection and estimated the limits of their variability and correlation with mothers. We took into account the livestock in two adjacent lactation periods of first-calf cows – 2016–2017 and 2018–2019. We registered low variance in milk yield and live weight between the lines in 2016–2017 and high variance in the realization of the potentials of daughters from intraline selections, which exceeded their peers in milk yield by 112–327 kg (p was less than 0.05) of milk with equal fat content. For most indicators, variability coefficients and standard deviations were higher in the groups of daughters of homozygous fathers with line crosses: for milk yield by 5.5%, for milk flow rate by 3.30%, for service period by 6.7%. When crossing lines heterozygous fathers were prepotent. However, milk productivity of daughters in all cases was higher with intraline selection. Similar results were noted when analyzing the indicators of first-calf daughters in 2018–2019. It was proposed to use homozygous stud bulls with a limited range of lines, as well as to identify possible ancestors of new related groups among homo- and heterozygous fathers that reduce group homozygosity for the vectors: “heterozygous fathers – intraline selection” and “homozygous fathers – line cross”. This was because we revealed a positive “mother-daughter” correlation in terms of milk yield and mass fraction of fat in the interval r = + 0.233–+ 0.364. It is important to pay attention to the prepotency of leading bulls during crosses, and for homozygous bulls – during intraline selection, when highly productive but heterogeneous groups of offspring with a low “mother-daughter” correlation are created: r was from -0.242 to + 0.106, respectively.
Keywords: Red-Motley breed; type of selection; milk production; variability; correlation; stud bulls; genotype; prepotency.
Author Details: N.A. Popov, D. Sc. (Biol), chief research fellow (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.).
For citation: Popov NA. Variability of productivity indicators in the offspring of Red-Motley cattle with different types of selection (significance of line breeding). Dostizheniya nauki i tekhniki APK. 2021;35(6):57-62. Russian. doi: 10.24411/0235-2451-2021-10610.