Horses are traditionally used in Kazakhstan as a source of food and as working and saddle animals as well. Here, for the first time, microarray-based medium-density single nucleotide polymorphism (SNP) genotyping of six traditionally defined types and breeds of indigenous Kazakh horses was conducted to reveal their genetic structure and find markers associated with animal size and weight. The results showed that the predefined separation between breeds and sampled populations was not supported by the molecular data. The lack of genetic variation between breeds and populations was revealed by the principal component analysis, ADMIXTURE, and distance-based analyses, as well as the general population parameters expected and observed heterozygosity (H_e and H_o) and between-group fixation index (F_st). The analysis revealed that the studied types and breeds should be considered as a single breed, namely the 'Kazakh horse'. The comparison with previously published data on global horse breed diversity revealed the relatively high level of individual diversity of Kazakh horses in comparison with the well-known foreign breeds. The Mongolian and Tuva breeds were identified as the closest horse landraces, demonstrating similar patterns of internal variability. The genome-wide association analysis was performed for animal size and weight as the traits directly related with the meat productivity of horses. The analysis identified a set of 60 SNPs linked with horse genes involved in the regulation of processes of development of connective tissues and the bone system, neural system, immune system regulation, and other processes. The present study is novel and introduces Kazakh horses as a promising genetic source for horse breeding and selection both on the domestic and international levels.

Background and Aim: Bacterial and viral infections affect the welfare of animals and lead to large economic losses in dairy cattle breeding due to decreased productive indicators and increased culling rates. In modern dairy farming, farmers are looking for effective solutions to prevent and minimize infectious disease risks. To this end, the most relevant study field is the search for gene sites that impact production and health. This study aimed to determine the nature of the distribution of the relative frequencies of alleles and genotypes of polymorphic prolactin (PRL) and nitric oxide synthase (NOS2) in Holstein cows and identify the relationship of these genes with resistance to mastitis and bovine leukemia. Materials and Methods: For this study, we chose cows because infectious diseases affect the amount of lactation and milk quality. Holstein cattle with mastitis and bovine leukemia were selected. Animal genotypes were determined by restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) products. The results were analyzed using a nonparametric statistical method using Microsoft Excel 2010 and Statistica 6.0. Results: In healthy animals, 94 genotypes were identified for both genes under study. For bPRL, bPRL-RsaIAA (72) was the most common genotype and bPRL-RsaIBB (4) the least; for NOS2, bNOS2-HinfIAB (47) was the most common genotype and bNOS2-HinfIAA the least (21). In animals with leukemia, 34 genotypes were identified. For PRL, bPRL-RsaIAA (25) was the most common genotype and bPRL-RsaIBB (2) the least; for NOS2, bNOS2-HinfIBB (17) was the most common genotype and bNOS2-HinfIAA (3) the least. In animals with mastitis, 67 genotypes were identified. For PRL, bPRL-RsaIAA (43) was the most common genotype and bPRL-RsaIBB (6) the least; for NOS2, bNOS2-HinfIBB (31) was the most common genotype and bNOS2-HinfIAA (7) the least. The distribution of genotypes of polymorphic bPRL and bNOS2 generally coincides, and bPRL-RsaIBB is the most common genotype. In groups of sick animals, the number of bNOS2-HinfIAA homozygotes was lower than that of the control group. In particular, the proportion of animals with the bNOS2-HinfIAA genotype with bovine leukemia was 8.7% and with mastitis was 10.3% compared with 22.4% in healthy animals. These data support the possible association of the bNOS2-HinfIAA genotype with resistance to infection. The frequency of the bPRL-RsaIB allele was higher in groups of sick animals. This allele is associated with increased milk productivity, suggesting that highly productive animals are less resistant to the incidence of viral bovine leukemia and mastitis of bacterial etiology. Conclusion: DNA amplification of Holstein cattle for the polymorphic regions of PRL and NOS2 using the PCR-RFLP method revealed a possible connection between the distribution of relative allele frequencies of bPRL and bNOS2 and resistance to viral and bacterial infections. Thus, in groups of sick animals, the frequency of bPRL-RsaIBB, associated with increased milk production compared with the theoretically calculated equilibrium value was higher and the number of homozygotes bNOS2-HinfIAA was lower than in the control group. In conclusion, animals with increased milk production were more prone to diseases, such as mastitis and bovine leukemia.

The work aims to analyze the associations of polymorphic variants of the PRL and BLG genes with resistance and susceptibility to mastitis in Holstein cows. The experimental study consisted of the selection of biomaterial samples from 250 heads of Holstein cows aged 3 years divided into two groups (healthy and with a confirmed diagnosis of mastitis). The determination of animal genotypes was carried out using polymerase chain reaction and restriction fragment length polymorphism. The study of the nature of the association of polymorphic variants of the PRL and BLG gene with resistance/increased risk of mastitis established a significant deviation from the theoretically expected distribution of bBLG-HaeIII genotypes in the group of animals suffering from mastitis (the value of χ² was 0.24). The bBLG-HaeIII^BB genotype can act as a marker of an increased risk of developing mastitis in Holstein cows; its frequency in the group of sick animals exceeds the frequency in the control group by more than 2 times (44.0 compared to 17.0%, respectively). The bBLG-HaeIII^AB genotype is significantly associated with mastitis resistance in Holstein cows; its frequency is 2 times lower than in the control group (28.0 compared to 54.0%).

The study aimed to determine the effectiveness of the use of genetic markers in cattle of the Kazakh white-headed breed identified using a genome-wide association study. The object of the study was the livestock of 790 Kazakh white-headed bulls bred in breeding farms of the Republic of Kazakhstan. The study adheres to rigorous ethical standards, with all procedures approved by the national scientific council of the national center for state scientific and technical expertise of the science committee of the ministry of science and higher education of the Republic of Kazakhstan, ensuring the welfare and ethical treatment of all animals involved. Genotypes of Kazakh white-headed breed animals were determined using gene seek GGP Bovine 150 K (Neogen) chips. Data processing was carried out using Genome Studio and Plink software. Seven genotype markers associated with an increase in live weight at the age of 12 months were found in cattle of the Kazakh white-headed breed and the greatest phenotypic effect was found in the genotype rs42549324/EPHA8/GG. Evaluation of the phenotypic effects of single nucleotide polymorphisms on the average daily weight gain of Kazakh white-headed breed animals showed that 13 genotypes that increased this trait, as well as 38 genotypes that decreased it, were associated with this trait. Analysis of the growth intensity and economic efficiency of breeding Kazakh white-headed breed animals showed that animals carrying the rs109490287/CC genotype had the largest absolute gain compared to the total sample; and animals with the rs136460595/SEMA6D/GG genotype, on the contrary, were characterized by the smallest absolute gain compared to the total sample. According to the results of the median test, 39 diplotypes were found in the Kazakh white-headed breed that increased live weight at the age of 12 months, of which 18 diplotypes had a more pronounced phenotypic effect than the separate genotype rs42549324/EPHA8/GG. The median test also allowed for revealing 53 diplotypes associated with increased average daily gain, of which 12 were characterized by a more pronounced phenotypic effect compared to individual marker genotypes, as well as 26 diplotypes affecting reduced indicators of average daily gain. Our findings contribute significantly to the field by identifying specific genetic markers that can be used to predict and improve meat productivity in the Kazakh white-headed cattle breed. This research not only adds to the genetic knowledge base of this particular breed but also offers practical applications for breeders aiming to enhance meat production efficiency through genetic selection.

This study concentrates on the sequencing of candidate genes linked to desirable agricultural qualities in Kazakh selection sheep, a region of considerable significance in improving sheep breeding and agricultural practices. The main goal is to examine genetic markers that impact important characteristics like as meat and wool quality, which are vital for the financial sustainability of sheep farming. The study focuses on certain candidate genes, namely MSTN, CAST, FAT1, and FZD3, which have been identified for their potential influence on agricultural features, using modern genetic sequencing techniques. The process entails the sequencing of specific sections of the genome and conducting a thorough examination of these genes to detect changes and their associations with desirable agricultural characteristics. The findings unveil significant genetic differences that are directly linked to the qualities of interest. These findings are crucial not only for comprehending the genetic composition of Kazakh sheep but also for their substantial impact on the domain of animal genetics and breeding. This work significantly enhances the current understanding by clarifying the genetic elements that impact important agricultural characteristics in sheep. Moreover, the discovery holds practical importance due to its potential applicability in selective breeding schemes. Through utilizing the knowledge acquired from genetic analysis, breeders can devise more effective and focused breeding tactics, ultimately resulting in enhanced agricultural output and quality in sheep farming. Consequently, this research shows great potential for progressing the field of animal genetics and enhancing the economic viability of sheep farming in Kazakhstan and other regions.