Based on the use of the best domestic and world gene pool of the Holstein breed, a domestic highly productive breed of cattle with a genetic potential of more than 10 000 kg of milk per lactation adapted to the climatic conditions of Siberia was created. When breeding it, different reproductive crosses were used. As a result, a competitive livestock breed with a population of 26 770 heads was obtained. The productivity of 10 129 cows at the time of breed testing averaged 7,461 kg of milk with a fat content of 3.78% and a protein content of 3.16%. In terms of milk yield and protein content in milk, they surpass Black-and-White cows by 1,460 kg and 0.05%, respectively. However, the animals of the original breed have a higher fat content of milk, by 0.14%. The live weight of cows of Sibiryachka breed is 36 kg (6%) more than that of Black-and-White cows. Young animals of the new breed are intensively growing and developing. At all ages, their live weight is higher than Black-and-White peers. The average daily increase from birth to one year for heifers of the new breed was 770 g, for Black-and-White peers – 700 g. For a growing period of up to 18 months, daily growth averaged 706 and 673 g, respectively. The live weight of heifers at 18 months is 424 kg, Black-and-White – 405 kg, which allows insemination of heifers of Sibiryachka breed 24 days earlier. The average yield of calves over 3 years in the new breed was 82.7%, in the original one it was 3.7% less. The period of use of the cows of the created breed is 3.47 calving, which is 8% more compared to the Black-and-White breed.

No abstract

The research was conducted in the fi eld of dairy cattle breeding with the use of genetic markers (SNPs) in order to study their relationship with the period of economic use of cows and their productivity. The object of the study was 186 cows of Simmental breed from the farm situated in Novosibirsk region. To study cows’ productivity (milk yield, fat, protein, the number of lactations) the data of zootechnical records was used. Molecular genetic research and statistical processing of experimental results were carried out according to generally accepted methods. The paper presents the results of the herd assessment by polymorphism of CSN3, PRL, BLG, TNF-α-824 genes, whose genotype frequency corresponds to a particular breed. Gene balance is not disturbed (χ2 = 0.147– 2,306). Homo and heterozygosity are approximately in the same ratio, except for the homozygosity of the gene PRL (0,736). Genotypes of cows desirable for productive longevity were identifi ed: BLGBB, PRLAA, PRLAB, TNF-αGG, whose number in the third lactation was over 70% in relation to the fi rst. The highest productive longevity was observed in animals with genotypes BLGBB and PRLAA, where 9.0% and 8.3% of their number, respectively, had a fourth lactation. Genotype BLGAA can be referred to as a desirable genotype for milk productivity. The difference from carriers of genotype BLGBB was 624 kg (p < 0.01). In the gene TNF-α, a higher yield in the second lactation at 787.3 kg was observed in cows with genotype TNFAA, compared to genotype TNF-αGG (p < 0.01). The same animals were found to have an increased content of fat in milk by 0.07% and protein by 0.05% (p < 0.01).

The results of studies on productivity and genotypic structure of cows of the leading lines of Sibiryachka cattle breed, associative links of CSN3, BLG, LALBA, LEP genotypes with economically important traits are presented. Comparative evaluation showed that Reflection Sovering bull cows had the highest milk yield of 6851 kg, fat content of 4.05% and protein content of 3.15%. The Siberian bull lines Frank 937, Uragan 27 and Kursa 1949 which are being shaped are inferior to them in milk yield, fat and protein content with values of 5246-5504 kg, 3.92-3.94%; 3.10-3.12% respectively. The genotypic structure of the herd and the leading lines is identified. The Vis Back Aydiala bull line is characterized by a higher frequency of CSN3AA and LEPTT genotypes by 18.2 and 11.0%, in comparison with the Reflection Sovering line. For other genotypes, the differences do not reach the confidence threshold. The average level of homozygosity for the genes studied varies from 51.2% to 73.4%. The highest homozygosity was found for the CSN3 gene in the Vis Back Aydiala line at 79.6%. The number of effectively acting alleles is 1.66-1.72; the degree of genetic variability is 40.2-42.7%. The cows with CSN3AB genotype had 544.0 kg higher milk yield than homozygous animals for the A allele (p <0.05). The highest milk yield was observed in BLGAA animals - 6790.1 kg, which is 947.2 kg higher than in cows with the alternative BLGВВ genotype (p < 0.01). Animals with the LEPCC genotype outperformed LEPTT cows in milk yield by 718.7 kg. No priority genotypes were identified for the LALBA gene. Also, no connection has been established between genotypes and the quality indicators of milk.

Objectives. The development of microfluidic systems is one of the promising areas of science and technology. In most procedures performed using microfluidic systems, effective mixing in microfluidic channels of microreactors (chips) is of particular importance, because it has an effect on the sensitivity and speed of analytical procedures. The aim of this study is to describe and evaluate the major parameters of the flow and mixing processes in a passive microfluidic micromixer, and to develop an information-measuring system to monitor the dynamics of flow (mixing) of liquids.Methods. This article provides an overview of the concept of microfluidic mixing chips (micromixers) and their classification, and analyzes the kinds of points of mixing and microfluidic channels for mixing. The article presents the description and calculations of the hydrodynamic similarity criteria (Reynolds, Dean and Peclet numbers), which are the critical parameters for creating and optimizing micromixers (for example, straight and curved channels in the flow rate range between 100 and 1000 µl/min). We have developed an information-measuring system to monitor the dynamics of flow (mixing) of liquids in a microfluidic channel, which consists of a microscope with a digital eyepiece (LOMO MIB, Russia), an Atlas syringe pump (Syrris Ltd., UK) and a passive mixing microfluidic chip of interest (made of clear glass). This system was designed to quickly illustrate the principles of mixing in microfluidic channels of different configurations.Results. The developed system has allowed carrying out a colorimetric analysis of the modes and dynamics of mixing two liquids (5% aqueous solution of azorubine dye and water) at the T-shaped mixing point, at the straight and curved (double-bend shaped) sections of the microfluidic channel of the passive-type micromixer with flow rates varying from 100 to 400 µl/min.Conclusions. According to the obtained calculations, the share of the advective mixing processes (formation of vortex flows and increase in the contact area of the mixed substances) in flowing liquids is significantly higher in curved microchannels. The developed information-measuring system to monitor the dynamics of flow (mixing) of liquids in a microfluidic channel is a convenient tool for optimizing the mixing modes in the channels of micromixers, and for designing new configurations of channels in microchips. It would allow intensifying processes and increasing the performance of microfluidic systems.