Viral diarrhoea is one of the most common and economically important diseases in cattle, causing significant losses in productivity and increased mortality in young livestock. Effective diagnosis of the disease requires the use of standardised sera that ensure high accuracy and reproducibility of laboratory results. Selection of sera to obtain standard sera for the diagnosis of bovine viral diarrhea represents a key challenge in the development of a standard sera panel. During monitoring in some regions of the Republic of Kazakhstan (Almaty, Mangistau, Karaganda, Turkistan oblasts) 399 samples of biomaterial from cattle were collected in private subsidiary farms and serological method of research was applied. In a serological test, specific diarrhea virus antibodies were detected in 310 serum samples. Comparative studies of sensitivity and stability of the positive sera with positive standard serum from the kit (ID Vet) were performed. During selection of sera, several factors were determined: specificity and sensitivity of the sera used, with consideration of the peculiarities of the epizootic situation in the region. This research work culminates in the production of a positive serum for the candidate from field-derived natural BVDV disease infections, and shortens the production cycle and saves costs.

Trans-fatty acids enter the human body with hydrogenated fats. The oil and fat industry must inform consumers about the fatty acid composition of food products, including the content of saturated fatty acids and trans-isomers. This study used the method of instrumental analysis to determine the fatty-acid profile and the content of trans-fatty acids in margarine. The research involved ten commercial samples of margarine. The fatty acid composition was studied by gas chromatography and mass spectrometry. The calibration graphs were based on standard mixes of methyl esters of individual fatty acids. Some oils appeared to contain ≥ 17% of palmitic acid. The total content of saturated fatty acids was 20.04–38.84%; the content of monounsaturated acids ranged from 27.92 to 36.81%, while that of polyunsaturated acids was between 14.51 and 28.99%. The margarine samples contained no butter (dairy) fat. All the samples contained 0.01–23.06% of trans-fatty acids. If the share of trans-fats exceeded 2%, it meant that the technical regulations had been violated, and hydrogenated oils had been introduced into the formulations. The highly specific mass spectrometric approach made it possible to detect trace trans-fatty acids, thus eliminating the chance of unreliable or false positive results. These methods proved to be an effective means of regulatory compliance and counterfeit prevention.

Equine trypanosomosis remains an important veterinary concern in regions where horses play a significant economic and cultural role. In Kazakhstan, comprehensive nationwide data on the seroepidemiological status of equine trypanosomes are limited. The aim of this study was to assess the serological distribution of equine trypanosomosis across all administrative regions of Kazakhstan using complement fixation testing (CFT). A total of 6065 equine serum samples were collected from seventeen regions between 2023 and 2025. Antibodies against members of the Trypanozoon subgenus were detected using a WOAH-recommended CFT protocol. Overall seropositivity was 4.73%, with substantial regional variation ranging from 0% to 16.52%. Statistically significant differences in seroprevalence were observed between regions (p < 0.001), and mixed-effects modelling indicated considerable regional clustering. PCR testing of seropositive samples did not confirm the presence of Trypanosoma equiperdum, while one sample tested positive for Trypanosoma evansi. These findings suggest that CFT seropositivity reflects exposure to equine trypanosomes rather than confirmed dourine infection. Given the inability of CFT to reliably distinguish between T. equiperdum and T. evansi, species-level attribution remains uncertain. This study provides the first nationwide overview of serological reactivity to equine trypanosomes in Kazakhstan. The results highlight regional heterogeneity in antibody detection and underscore the need for expanded molecular surveillance and improved species-specific diagnostic tools to clarify the epidemiological status of equine trypanosomosis in the country.

Trypanosoma evansi is a vector-borne protozoan parasite responsible for surra, a disease that affects a wide range of domestic and wild animals, causing severe health consequences and significant economic losses. This study aimed to investigate the histopathological effects of T. evansi infection in rabbits under controlled experimental conditions and assess the potential of rabbits as a suitable model for studying this disease. Sixteen rabbits were divided into infected and control groups. The infected group received an inoculation of T. evansi isolated from cattle. Clinical signs were monitored, and tissue samples from the liver, lungs, spleen, myocardium, and kidneys were collected for histopathological evaluation. Microscopic analysis revealed marked pathological changes in infected animals, including granular and fatty degeneration of hepatocytes, hyperemia, emphysema and exudative inflammation in the lungs, myocardial dystrophy, spleen hyperplasia, and degenerative changes in renal tissue.These alterations reflect systemic involvement, indicating the pathogenicity of T. evansi and its ability to affect multiple organ systems. The experimental model reproduced classical features of the disease, such as anemia, tissue edema, and hemorrhages, supporting the relevance of rabbits as a viable model for trypanosomiasis research. This study contributes to a better understanding of host-pathogen interactions and pathogenesis in surra. The results offer valuable insights for the development of diagnostic tools, treatment strategies, and vaccine research. Moreover, the established rabbit model may facilitate future investigations into the biology and virulence of T. evansi strains circulating in Kazakhstan and beyond.

The valorization of dairy by-products, particularly whey, represents a key challenge and opportunity in sustainable food systems. This study aimed to evaluate the physicochemical and amino acid composition of milk and whey-derived products and to identify optimal whey–milk mixtures using integrated multivariate and desirability-based approaches. Ten model systems (M1–M10) were prepared with increasing whey content (7.5–75%), and their composition was analyzed using infrared spectroscopy and high-performance liquid chromatography. Multivariate analysis, including PCA and correlation heatmaps, revealed that protein, casein, TS, SNF, and amino acid fractions (ΣEAA and ΣBCAA) were the primary drivers of compositional variability, whereas lactose and acidity-related parameters contributed to secondary differentiation. Desirability function analysis was applied by integrating nutritional quality, functional balance, and sustainability score into a composite index. The results demonstrated that intermediate formulations achieved a more balanced profile compared with extreme compositions. Among all mixtures, the formulation containing 30% whey (M5) showed the highest overall desirability within the evaluated parameters, reflecting a favorable balance between compositional quality and whey utilization. These findings highlight the potential of integrated analytical approaches for the development of nutritionally optimized and resource-efficient dairy systems.