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: Staphylococcus aureus is the most frequent and ubiquitous cause of mastitis in cows. In recent decades, antibiotic resistance has rapidly spread among infectious disease pathogens in Kazakhstan and globally. This study examined the phenotypic and genotypic resistance of S. aureus strains obtained from cattle milk to antibiotics. Materials and Methods: In 2021 and 2022, 675 cow milk samples were collected from 16 dairy farms in Northern Kazakhstan. Staphylococcus aureus was identified using culture and biochemical methods. The nature of antibiotic resistance was determined by the disk diffusion (DD) method. The distribution of antibiotic resistance genes was determined by polymerase chain reaction. Results: Among the obtained S. aureus isolates, high levels of resistance to β-lactam antibiotics (100%), tetracyclines (95.4%), fluoroquinolones (95.4%), and macrolides (60.92%) were observed. Meanwhile, the lowest levels of resistance were identified for sulfonamides (21.84%) and aminoglycosides (27.59%). All the obtained isolates were positive for the nuc gene encoding thermonuclease. The blaZ, ermC, and tetK genes were detected in 45.9%, 77%, and 83.9% of the studied S. aureus isolates, respectively. Conclusion: The results indicate a high prevalence of antibiotic resistance in S. aureus isolated from cows with clinical and subclinical forms of mastitis in Northern Kazakhstan. In addition, the prevalence of resistance was higher when evaluated by the DD method than when detecting the specific antibiotic resistance genes blaZ, tetK, and ermC, indicating the need for deeper analysis of the phenotypic and genetic determinants of antibiotic resistance. Keywords: antibiotic resistance genes, cow milk, polymerase chain reaction, Staphylococcus aureus strains.

Runs of homozygosity (ROH) are contiguous stretches of homozygous genotypes that are passed from parents to their offspring. ROHs are suitable for determining population history, inbreeding rates, and the genetic relationships between individuals in the populations, as well as to detect candidate genes responsible for economic traits in farm animals. In this study, we observed that the Kazakh white-headed (KWh) cattle breed (ROH n = 55,976) had a higher number of ROH compared to the Auliekol (AK) breed (ROH n = 13,137). When calculating the mean length of ROH, there were considerable differences between Kazakh white-headed (211.59 ± 92.98 Mb) and Auliekol (99.62 ± 46.48 Mb) populations. The maximum length of ROH was higher in Auliekol cattle (510.25 Mb) than in Kazakh white-headed cattle (498.91 Mb). The average inbreeding coefficient rate was equal to 0.084 ± 0.037 in Kazakh white-headed cattle and 0.039 ± 0.018 in Auliekol cattle. The high frequency of genomic regions showed that the strongest patterns were observed on chromosomes 2, 6, and 26 for KWh and 1, 5, and 14 for AK. The estimation of ROH numbers per animal showed that the number of ROH decreased with increasing ROH length in both populations. The genomic inbreeding coefficient of both cattle breeds was calculated based on the ROH, and ancient inbreeding was observed. The harbored genes within ROH islands were associated with meat growth and milk production.

Background and Aim: The market demand for the quality of milk and dairy products, in particular in terms of such indicators as fat content, the amount and composition of milk protein, etc., is growing. Thus, the need for the selection of dairy herds using genetic markers associated with qualitative traits of milk productivity is becoming urgent. This study aimed to determine the preferred and undesirable genotypes of the AluI polymorphism of the growth hormone gene and SnaBI polymorphism of the insulin-like growth factor-1 gene associated with milk productivity and quality indicators of the black-and-white breed. The genotypes of animals were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Materials and Methods: Samples of the black-and-white breed from Kazakhstan served as the research subjects. The polymorphism of the growth hormone and insulin-like growth factor-1 genes was determined by PCR-RFLP. The relationship of bGH-AluI and bIGF-1-SnaBI polymorphisms with productivity was assessed (fat, protein, and milk yield for 305 days of lactation, live weight, somatic cells, and milk production coefficient) by analysis of variance using Statistica 6.0 software. Results: The black-and-white cows with the bGH-AluILV genotype had significantly higher milk yield in 305 days (3174.5±157.2 kg) than those with the bGH-AluILL (2940.0±152.6 kg) and bGH-AluIVV genotypes (2964.0±36.0; p<0.05). The milk fat content of cows with genotypes bGH-AluILV and bGH-AluILL (121.8±6.5 and 120.6±10.2, respectively) was significantly higher than those with bGH-AluIVV genotype (109.8±10.8; p<0.05). The black-and-white cows with the bGH-AluILV genotype (96.7±5.3) had significantly more milk protein than those with the bGH-AluILL (90.3±5.6) and bGH-AluIVV (86.9±4.6) genotypes (p<0.05). There were no statistically significant differences in the indicators of milk productivity of cows with different genotypes of bIGF-1-SnaBI polymorphism. Conclusion: The results showed that the bGH-AluILV genotype was preferred for the black-and-white breed. The study demonstrated that genotype determined the relevant qualities, while the conditions of feeding, maintenance, and industrial technology provided the manifestation of this genotype. Thus, cows of the same (Wis Burke Ideal) line, having common ancestors in close (IV–V) ranks but living in different farming conditions, had large differences in milk productivity level. The variation was 2046 kg or 67.6% of milk per lactation.

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.

Brucellosis is a particularly dangerous zoonotic disease that is widespread in animals and humans. Despite the fact that more than 120 years have passed since the discovery of the pathogen and the disease has been well studied by domestic and foreign researchers, the problem of brucellosis remains relevant in many countries of the world. A number of economically developed countries have achieved some success in controlling bovine brucellosis caused by Brucella abortus. Results for control of brucellosis in small ruminants caused by Brucella melitensis are more modest. In some developing countries, the epizootic situation for bovine brucellosis is worsening. Brucellosis caused by B. melitensis is also a major public health problem. According to the World Health Organization (WHO), more than 500 000 cases of newly diagnosed brucellosis are reported each year in more than 170 countries, more than half of them in the Eastern Mediterranean and Middle East. In brucellosis-prone regions, the actual incidence can be 10 to 25 times higher than officially reported. In brucellosis-endemic areas, where brucellosis is a deep-rooted problem, the infection has global, far-reaching negative consequences for the health and economy of states. The main objective of the studies was to monitor the epizootological situation of animal brucellosis in the Republic of Kazakhstan (RK).