No abstract

Los componentes biológicamente importantes de la leche son la grasa, la proteína, la lactosa y los minerales. Gracias a ellos, es una parte significativa y esencial de la dieta humana. En los últimos años, entre los componentes de la proteína, la beta-caseína ha ganado gran importancia y popularidad entre las personas que se preocupan por su salud. Por lo tanto, la composición beta-caseína de proteínas lácteas y productos lácteos se ha convertido en una característica de cría importante de los animales lácteos. Este estudio tiene como objetivo evaluar las perspectivas para el uso del polimorfismo del locus de beta-caseína en la selección de ganado marrón para determinar la posibilidad de crear rebaños de piscina genética con características únicas de la leche – exclusivamente con beta-caseína A2. La estructura genética identificada de las vacas y toros de la raza Lebedyn por beta-caseína, la participación de los toros de la raza original de la raza suiza marrón (BS) según el modelo recíproco propuesto, permite formar poblaciones homocigotas de genotipos A2A2 en generaciones posteriores. Un enfoque individual para las cuestiones de coincidencia y selección, control, con la ayuda de métodos de diagnóstico de ADN, por los procesos de transmisión de genes de padres a descendientes, permitirá reponer rebaños con portadores del gen A2. El modelo de cría propuesto en combinación con el uso de espermatozoides sexados y el genotipado de novillas, tiene la mayor aceleración de selección de la creación de una población homocigota para beta-caseína A2A2.

Thanks to the breeding work carried out to create the Sumy intra-breed type of the Ukrainian Black-and-White dairy breed, it was possible to increase the level of milk productivity of animals, which today amounts to more than 6.0 thousand kg of milk. The level of milk yield is the main in the system of dairy cattle breeding. The quality indicators of dairy raw materials are also of great importance for the economy of milk production. This issue has become particularly important recently, which is associated with the negative consequences of using the Holstein breed, namely, a decrease in the level of fat and protein in milk compared to local breeds. Researchers attach great importance to the study of individual fractions of milk protein and their impact on technological qualities during its processing. Therefore, new achievements in genetics and biotechnology have been widely applied in practice. Genetic markers are even more widely used in global dairy cattle breeding. The latter allow us to identify individual genotypes at many loci and provide information about population parameters, such as alleles and genetic frequencies. Dairy cattle breeding programs in many countries around the world take into account genetic research. This is due to the possibility of rapid improvement of the quality and technological properties of milk. The effect of capa-casein genotypes on milk quality has been studied by many scientists. The capa-casein gene polymorphism has been known since 1964. By 1988, the capa-casein gene of cattle was isolated and its structure was characterized. To date, thirteen genetic variants of cattle capa-casein have been described: А, В, C, D, E, F, Н, J, I, Х, Az, A1. Genetic variants A and B are the most common, while other alleles are quite rare. The interest in this casein fraction is due to the fact that cheese from the milk of cows with the BB genotype thickens 25% faster and has a clot twice as dense as milk from cows with the AA genotype, and accordingly the yield of cheese from the milk of cows of the BB genotype is 10% higher than from the milk of cows of the AA genotype. The aim of our work was to study the features of the formation of the genealogical structure of the Ukrainian Black-and-White dairy breed in the Sumy region and its influence on the frequency of capa-casein genotypes. Materials and methods. The research was conducted at the State Enterprise "Experimental Farm of Institute of Agriculture of Northern East of National Academy of Agrarian Sciences of Ukraine" of Sumy region on the number of cows of the Ukrainian Black-and-White dairy breed (n = 23) (first group) and Sumy intra-breed type of the Ukrainian Black-and-White dairy breed (n = 40) (second group). Retrospective studies were conducted by studying the ORSEC SUMS database for the period from 1976 to 2020. The capa-casein gene polymorphism was determined in the genetic laboratory of the Institute of Physiology n. a. Bogomolets of NAS using real-time molecular biological analysis of allele recognition by polymerase chain reaction (PCR). The results obtained were processed by the method of variational statistics using the statistical 6.0 software package. The formation of an array of Sumy intra-breed type of Ukrainian Black-and-White dairy breed on the farm was started in the mid-80s of the last century. So on the breeding stock of the Lebedinian breed began to use the sperm of bulls-producers of the Holstein breed. Bulls-producers of the Holstein lines Aidial 1013415, S. T. Rokita 252803, Sowering 198998, M. Chiftein 95679, Eleweishna 1491007 and Astronaut 1458744 were involved in this process. Further formation of the genealogical structure of the herd of the Ukrainian Black-and-White dairy breed and Sumy intra-breed type had their own characteristics. Thus, in the period from 1991 to 2000, the breeding stock of animals of the Ukrainian Black-and-White dairy breed came from bulls-producers of 8 lines, while Sumy intra-breed type belonged to 13 lines. The most common lines in the first animals were – Aidial 1013415, Sowering 1989986, M. Chiftein 95679 in the second – Eleveishn 1491007, M. Chiftein 95679, Chief 1727381. The period since 2001 has been characterized by the fact that the formation of the genealogical structure of black and white herds in Sumy region was accompanied by the use of purebred bulls of the Holstein breed. The share of bulls of Ukrainian Black-and-White dairy breed was less than 10%. This contributed to the fact that the breeding stock of breeding herds belonged mainly to three Holstein lines: Chief 1427381, Eleweishna 1491007 and Starbuck 352790. We have found that the frequency of capa-casein is somewhat different in animals of different origins. Thus, animals of Sumy type were characterized with a higher frequency of both the desired homozygous BB genotype (20%) and the homozygous AA genotype (60%). A higher frequency of the heterozygous AB genotype (36%) was characteristic of animals of Ukrainian Black-and-White dairy breed. At the same time, the frequency of alleles was almost the same. There is a difference in the frequency of genotypes and alleles by capa-casein between first-born animals of different parental affiliation. Altodegri 64633889 bull daughters were characterized by a higher frequency of homozygous desired BB genotype. High frequencies of heterozygous AB genotypes were found at daughters of bull Morian 1402173979. All daughters of the bulls Detective 349159846, Maygold 534651702 were homozygous AA. The highest frequency of the BB allele was characteristic of the daughters of the bull Altadegri 64633889. Conclusions. According to the results of the study, the peculiarities of the formation of the genealogical structure of the herd of the Ukrainian Black-and-White dairy breed, which was formed according to various programs, were established. The genealogical structure at the beginning of herd formation had its own characteristics and depended on breeding directions. The period of the last twenty years in the region is characterized by the total use of Holstein Bulls on the breeding stock of the Ukrainian Black-and-White dairy breed, which explains the linear belonging of the majority of livestock to the lines of Chief 1427381, Eleveishna 1491007 and Starbuck 352790. The consequence of this is a high conditional bloodline in the Holstein breed of the firstborn. According to the results of genetic research, it was established that in the herd of Ukrainian Black-and-White dairy breed the genotype of cattle by capa-casein significantly depended on the origin. Thus, Sumy type animals are characterized by a higher frequency of homozygous genotypes – 80%, while the frequency of alleles in animals of different origins is almost the same. Parental origin also had a significant effect on the genotype of animals on this basis.

The aim of the work is to analyze the distribution of allelic variants of genes associated with the signs of milk productivity of animals, in particular, Kappa–casein loci and to establish on its basis genetic structure of the population of producers of the Lebedinian breed by the Kappa-casein gene. Material and methods of research. The material for the research was the sperm of bulls of the Lebedinian breed cattle (n = 12 heads), evaluated by the quality of offspring. Determination of Kappa-casein gene polymorphism was carried out by PLR-PDFR method in the laboratory of Institute of Animal Husbandry of NAAS. Statistical data processing was carried out on a PC according to the generally accepted methodology using MS Excel software. Research result. The genetic study of the sperm production of 12 bulls of the Lebedinian breed by the gene Kappa-casein (CSN3) was aimed at studying the genetic characteristics of each of the bull and taking into account the possibilities of using their sperm production in custom-made sails. The analysis of the genealogical structure showed that 12 bulls were referred to 8 lines. Of the 12 pedigrees, 5 purebred Lebedinian bulls and 7 crosses with Swiss breed bulls. Among the studied bulls by the CSN3 gene, two bulls of the desired homozygous genotype BB were identified – Final 1008, Zaychyk 17000; 6 bulls were homozygous for the AA genotype, 4 bulls were heterozygous. The frequency of the desired BB genotype among the studied animals was 0.17, and the frequency of carriers of the AA genotype was 0.50. The frequency of carriers of heterozygous genotype AB was 0.33. The frequency of carriers of allele A in the studied animals is 0.66, which is almost twice the frequency of allele B – 0.34. The frequency of allele B in Kappa-casein in herds for the preservation of the Lebedinian breed can be increased by using bulls who have a B-allelic variant of Kappa-casein in their genome. Summary. The bulls of the Lebedinian breed recorded a sufficiently high frequency of allele variant in the Kappa-casein locus, which allows for further selection of cattle aimed at increasing the suitability for cheese production of milk. The presence of identified bulls with desirable genotypes of BB and AB Kappa-casein makes it possible to create herds that produce milk with higher technological properties in the production of cheese.

To study the polymorphism of β-casein gene and its effecton the quality of cow's milk the research was conducted in the breeding herds of Ukrainian Black-and-White Dairy, Lebedynand Simmental breeds. Genotyping of 200 head of cattle wascarried out. Determination of β-casein gene polymorphismwas performed in the genetic laboratory of Bohomolets Institute of Physiology. The TagMan@Genotyping system and aset of primers and probes were used for allelic discrimination.It was found that the frequencies of alleles A1 (0.294-0.380) and A2 in the locus of β-casein gene differed in animals of different breeds. The highest frequency of the desiredallele A2 had the population of Lebedyn breed cows (0.706),while the lowest was in Simmental ones (0.620). The frequency of A1 allele was the lowest in the cows of Lebedyn breed(0.294), and the highest in Ukrainian Black-and-White Dairybreed (0.380). Accordingly, the frequencies of genotypesA1A1, A1A2 and A2A2 differed depending on the origin. Thedesired genotype was more common in animals of UkrainianBlack-and-White Dairy and Lebedyn breeds (53-52%, respectively). Heterozygous genotype occurred more frequently in animals of Lebedyn and Simmental breeds (37%). Thehighest frequency of A1A1 genotype was characteristic ofanimals of Ukrainian Black-and-White Dairy and Simmentalbreeds (20%). According to the genetic and statistical analysis, there was an excess of homozygous variants of A1A1 andA2A2 in β-casein locus, and a lack of heterozygous A1A2.At the same time in animals of Ukrainian Black-and-WhiteDairy breed, the difference between the actual and expecteddistribution of genotypes was statistically significant.There was a difference in the quality characteristics ofmilk between animals of different genotypes. In animals ofdifferent breeds, the content of certain components of milkdid not vary equally depending on theβ-casein genotype, butthis difference was statistically insignificant.Cows of Ukrainian Black-and-White Dairy breed withhomozygous A1A1 genotype exceeded others in terms offat content, those with heterozygous A1A2 genotype had anadvantage in terms of protein, lactose and dried skimmedmilk remainder (DSMR). Animals of Lebedyn breed with theA2A2 genotype predominated animals of other genotypes inall investigated indicators of milk quality. Animals of Simmental breed with the desired A2A2 genotype had a lower fatcontent in milk compared to animals of other genotypes andthe average values in the sample. These animal together withA1A1 homozygotes had higher protein content in milk thanheterozygous animals and average values in the sample. Inour opinion the small number of experimental animals wasone of the reasons for the lack of a definite difference betweenthe average values of the milk components of cows of different β-casein genotypes. Key words: breed, fatcontent, proteincontent, kappacasein, genotype, allele, sire.