Purpose: to study the origin of agricultural populations of Rangifer tarandus in the Far North-East of Russia.

Materials and Methods. Special scientific literature based on archival primary sources and zootechnical information from annual reports of reindeer herding farms in the Magadan Region and the Chukotka Autonomous Okrug were used. An analytical research method was used, and the reindeer population of the North-East served as a model.

Results. Domestic reindeer populations in the Arctic and Subarctic zones of the Far East were formed on the basis of combining the population of nomadic aborigines. Reindeer herding in the 1930-1960s was characterized by permanent economic transformations. Joint grazing partnerships were created by combining the reindeer of private owners. During the era of total collectivization, the latter began to be part of larger economic structures - artels, collective farms. In the 1930-1940s, the Dalstroy State Trust created a number of large reindeer herding state farms in the Northeast to provide food for the growing population of mining regions. During the reorganization, herds were regrouped and large masses of animals were mixed, which led to a significant increase in migration, introgression, biodiversity, enrichment of gene pools, an increase in heterozygosity and heterosis, growth in productivity, live weight, fertility, viability of reindeer, and a decrease in barrenness as a result of crossing genetically unrelated and ecologically different animal groups. Such economically significant features as business yield of calves, survival of the herd, live weight, fatness characterize the reproductive and adaptive properties of the North-East reindeer as sufficiently adapted to the extreme conditions of the range. The largest population of reindeer in the USSR was formed.

The aim of the presented work was to study the variability of morphometric and exterior characteristics of female kamloops trout, to find the dependence of female weight on morphometric characteristics.

Materials and methods. The research was conducted in November 2023 at the Parola fish farm located in Lake Ladoga. The object is three—year-old rainbow trout of the kamloops breed of Finnish origin. The planting material was brought to the fish farm in the spring of 2020 and was grown in cages. Upon reaching the age of three, 86 females with optimal phenotype parameters were selected and labeled from the total group of fish. The selected livestock was evaluated according to a number of indicators: external inspection, body measurements, morphometric and exterior. Studies of the variability of some morphobiological characteristics and body weight of female rainbow trout of the kamloops breed were carried out using modern mathematical statistics methods.

Results. It was revealed that the normal weight of three-year-old female rainbow trout of the Kamloops breed is in the range of 4218...7595 g, the normal total body length is 62,2...74,4 cm, the normal commercial body length is 57,8...69,6 cm, the normal Smith length is 60.8...74.3 cm, the normal high-spin index is 31,3...38,2, the normal bighead index — 20,1...24,8, the normal fatness coefficient is 1,5...2,2. It is recommended to take this into account when carrying out breeding work and fish selection during reproduction. As a result of regression analysis, adequate power-law models were obtained that describe the relationship between the body weight of female kamloops trout and the main morphometric features: total body length, fishing length, body length according to Smith, the highest body height, the largest body girth, and head length, which can be used to predict the body weight of female kamloops trout.

Conclusion. The results obtained make it possible to better assess the growth and changes in the linear weight and exterior parameters of fish during cultivation, and are also of great practical importance when carrying out breeding work with rainbow trout of the Kamloops breed.

Purpose: to study the current state of breeding cattle of the Sychevka breed in the territory of the Russian Federation, taking into account the level of Holstein.

Materials and methods. The results of bonification and data from breeding and zootechnical accounting in breeding farms of the Smolensk region for 2023 were used. The number of cows of the Sychevka breed in the Smolensk region was divided into 5 groups, depending on the blood type of the improving Holstein breed of red-mottled color (%): less 17,5; 17,5—25,0; 25,1—50,0; 50,1—75,0 and 75,1 or more.

Results. The analysis of dairy productivity of Sychevka cattle in the Russian Federation is carried out. According to the study, an increase in the milk yield of Sychev cattle in 2023 compared to 2019 in the Russian Federation averaged 793 kg. In animals in the Smolensk region with a blood content of more than 50 % of the Holstein breed, milk production is higher than in animals with a lower blood content, with a fat content in milk from 3,8 % to 4,0 %. The effect of blood supply on the live weight of animals has not been established. Animals with a blood content of more than 75 % have a good level of nutrition, and their milk yield for maximum lactation is higher than that of cows with less blood.

Purpose: to analyze the livestock population of the main beef breeds, the state of beef production and the industrial use of cows.

Materials and methods. The methodological basis of the study was made up of systematization techniques, logical and comparative statistical analysis. The analysis was carried out using domestic and foreign bibliographic databases, yearbooks on breeding work in beef cattle breeding in farms of the country.

Results. Regardless of the analysis period, the largest number of livestock was observed in the Kalmyk breed, the proportion of which amounted to 30,5—33,8 % of all probonitized cattle of beef breeds and increased by 3,3 abs. % compared to 2022. The number of Aberdeen Angus cattle in 2022 amounted to 26,5 % of the total number of beef breeds, while a year later it decreased to 16,9 %, which was less than the number of all other studied breeds. With the exception of Aberdeen Angus, the number of probonitized livestock of Kalmyk, Kazakh White-Headed and Hereford breeds increased, although slightly. Of all the analyzed beef cattle breeds, Aberdeen Angus cattle had an earlier age at the first insemination, with values of 16 months, followed by representatives of the Kalmyk breed (23,8 months), which indicates the late maturity of these animals. The remaining breeds were inseminated in the period of 18—20 months and occupied an intermediate position between the extreme values of the trait. In terms of age of withdrawal from the herds, the best values were shown by cows of the Kalmyk and Kazakh White-Headed breeds, which averaged 6,8—6,9 calvings. Herefords were characterized by a lower age of cow retirement among the studied breeds, the values of which were 0,5—1,3 calvings lower. A low level of calf output per 100 Aberdeen Angus cows was revealed — 56 heads, which is lower than the indicators obtained from other breeds of meat productivity by 27— 29 heads.

Conclusion. The results obtained make it possible to better assess the growth and changes in the linear weight and exterior parameters of fish during cultivation, and are also of great practical importance when carrying out breeding work with rainbow trout of the Kamloops breed.

Purpose: to study genetic polymorphism of blood proteins in Holstein and Simmental cattle breeds.

Materials and methods. The blood of Simmental (n=368) and Holstein (n=266) cows served as the material for the study. Blood samples were analyzed by vertical electrophoresis in a two-layer polyacrylamide gel, where the following polymorphic proteins were analyzed: transferrin (Tf), posttransferrin-1 and 2 (Ptf-1 and 2), hemoglobin (Hb), amylase (Am), catalase (Kt), prealbumin (Pa).

Results. Simmental cattle retain polymorphism of the hemoglobin locus, while in Holstein cattle it remains monomorphic. The Holstein breed is characterized by a high frequency of the Tf A allele and a low frequency of the Tf E allele, as well as the absence of the Am A allele in comparison with the Simmental breed. In the studied cattle populations, a violation of the genetic balance is observed at four loci in the Simmental breed (Tf, Kt, Pa, Am) and at two loci in Holstein cattle (Ptf-1 and Am) due to an excess of homozygous genotypes. The number of effective alleles per locus in the studied breeds averaged 1,79 (in Holsteins) and 1,82 (in Simmentals). The highest value of the number of effective alleles was observed at the transferrin locus (3,00—3,03).

Hypoxia is a widespread pathological process that manifests itself in insufficient oxygen supply to the tissues of the body and/or impaired cellular uptake. This condition triggers a complex of secondary nonspecific metabolic and functional disorders, as well as adaptation reactions. Regardless of the causes and conditions contributing to the development of hypoxia, it leads to failures in the processes of biological oxidation and energy metabolism. The aim of the study was to investigate the disorders of lipid metabolism in rat heart tissues and the effect of plant antihypoxants on them during modeling of acute histotoxic hypoxia.

Materials and methods. The studies were performed on white mongrel rats weighing 240-260 g. A model of histotoxic hypoxia was used. Lipoproteins in rat heart tissues were determined by electrophoretic method according to the standard technique using standard sets of chemical reagents from Lahema (Czech Republic). Phospholipid spectrum in rat heart tissues was determined by thin-layer chromatography using silicone plates of Silufol (Czech Republic).

Results. The results of the studies showed that against the background of acute histotoxic hypoxia lipid metabolism disorders developed, characterized by a decrease in the concentration of lecithin, cephalin, phosphatidylserine, cardiolepin and an increase in the concentration of sphingomyelin and lysolecithin, as well as a decrease in the total concentration of phospholipids in general. The use of antihypoxants leveled the negative effect of histotoxic hypoxia on lipid metabolism in rat heart tissues and the most pronounced positive effect was observed when using a mixture of extracts of medicinal raspberry and black currant in the ratio of 1:1.

The article presents an analysis of the effects of stress of various etiologies on the body of a fast-growing bird, with an emphasis on physiological, immunological and metabolic disorders. The main stress factors, including heat, cold, light, high-density planting, fodder and immune stress, as well as their consequences for poultry health, are considered. Special attention is paid to changes in the biochemical composition of blood, mechanisms of oxidative stress, disorders of the intestinal microbiota and changes in gene expression under the influence of stressors. The work shows that heat stress leads to a significant decrease in productivity, metabolic disorders and activation of oxidative processes, which is confirmed by an increase in cortisol levels and a decrease in thyroid hormones. Cold stress causes structural damage to tissues, including the heart and intestines, as well as an imbalance of pro-inflammatory cytokines. The light regime significantly affects the stress level, which affects the ratio of heterophiles and lymphocytes. Planting density is associated with an increase in leukocytosis and a change in electrolyte balance. Lipopolysaccharide-induced immune stress (LPS) leads to significant changes in the microbial composition of the intestine and correlates with the modulation of genes related to inflammation and metabolism. The research results emphasize the need for further research in the field of stress management in poultry farming, including the development of feeding programs using modern adaptogens. The purpose of this review is to summarize current scientific data over the past 5 years on the etiology of various types of stress in intensive poultry farming, as well as to establish their effect on the body of fast-growing poultry. This study will be useful as a theoretical and fundamental basis for the development of programs to enhance the adaptive capabilities of the bird's body, including through nutritional factors.

Objective: to study the relationship between biochemical blood markers in tigers and to determine age-related predisposition to impaired renal filtration capacity.

Materials and methods. To achieve this goal, the results of a biochemical blood test from tigers (N=41) aged from two months to 18 years were statistically analyzed. The tigers belong to various organizations: zoos, nurseries, circuses, and the "Tiger House" hospice. The blood test was conducted using "Randox" test systems. The results of creatinine, urea, inorganic phosphorus, potassium, and creatine kinase determination were used in this study. The biochemical test results were divided into 5 groups based on age. For statistical processing of the results, the Microsoft Excel software package was used, in which the functions of data grouping, calculation of the mean value (M), error of the mean (m), determination of the variation coefficient and the correlation coefficient were performed.

Results. A progressive increase in creatinine concentration in age dynamics from 83,6 ± 16,1 μmol / l to 637,9 ± 224,3 μmol / l was revealed. A unidirectional increase in the level of creatinine and urea in tigers aged from 7 to 18 years was determined, at a young age, the concentration of urea almost does not change and ranges from 9,91 ± 0,83 mmol / l to 11,62 ± 1,67 mmol / l. The change in the concentration of inorganic phosphorus in connection with age can be illustrated by a parabolic curve with the lowest value corresponding to the age period of 3—6 years. No significant age-related fluctuations in serum potassium concentration were found in tigers; the differences between the lowest and highest values were 9,5 %. Blood creatine kinase activity did not show any significant changes up to the age of 12; only in the oldest age group of 14—18 years did the enzyme activity increase by 5,3 times. A wide range of creatinine concentrations was observed in all age groups; the variation coefficient ranged from 27,7 % to 89,8 %. An examination of the correlation coefficients when comparing creatinine concentration with other parameters revealed a close positive relationship with urea both in the entire sample and in the age range from 7 to 18 years. No significant correlation relationships were found for potassium.

Conclusion. Blood creatinine levels in tigers in all age groups are subject to significant fluctuations, and this is a reason to substantiate objective reference intervals for these animals. The concentration of creatinine in the blood of tigers increases progressively with age. At a young age, this trend is not directly related to the deterioration of the filtration function of the kidneys, since up to 6 years of age, animals do not show a parallel increase in the concentration of urea and inorganic phosphate. In the older age period from 7 to 18 years, tigers show a predisposition to kidney diseases, since along with an increase in creatinine in the blood, there is an increase in the concentration of urea (r = 0,929) and inorganic phosphate (r = 0,687).

Despite its relatively widespread, many physiological parameters, including blood, in ferrets still need to be studied. Leukocyte indices are calculated values obtained on the basis of leukogram values. As a rule, they are not a direct indicator of a specific disease, however, they are important indirect markers that can help in compiling a list of differential diagnoses.

The aim of the study was to evaluate the indicators of leukocyte indices in clinically healthy ferrets, as well as to compare the obtained indicators with some available reference values in other animal species.

Materials and methods. The morphological parameters of the blood of 10 clinically healthy ferrets were analyzed. In the stabilized blood, the number of leukocytes and the leukogram were determined according to generally accepted methods, followed by the calculation of the following leukocyte indices: Krebs index (KI), leukocyte intoxication index (LII), nuclear index of GD Dashtyantsa (NI), leukocyte displacement index (LDI), leukocyte index (LI), neutrophil-monocyte ratio index (NMRI), lymphocyte-monocyte ratio index (LMRI). 

Results. The results of the presented study can potentially improve the diagnosis and prognosis of various diseases in ferrets, identify markers of early mortality, and assess the dynamics of pathological processes. The indicators of leukocyte indices used indirectly reflect the degree of activity of the immune system, including phagocytosis, cell proliferation and regeneration, as well as the interaction of humoral and cellular immunity. In the future, the study is planned to expand by increasing the sample size, analyzing individual diseases, physiological conditions, dietary effects, and the relationship with the severity of the condition, duration, and quality of life.

The study of metabolic disorders caused by hypoxia is an important area of medicine and biochemistry, since such conditions can be key factors in the development of serious clinical diseases. One of the main consequences of hypoxia is the development of hypoenergetic states, in which there is increased lipid hydrolysis. At the same time, active synthesis of fatty acids is also observed, which leads to their increased concentration in blood and tissues. The multiplicity of pathophysiological changes in the organism under hypoxia requires the search for effective antihypoxants. Promising antihypoxants are extracts of black currant and medicinal raspberry.

The aim of the study was to investigate the peculiarities of fatty acid metabolism in rat heart and brain tissues against the background of acute histotoxic hypoxia and antihypoxant loading.

Materials and methods. The studies were performed on 180 white mongrel rats. The animals were divided equally into 6 groups. According to group affiliation, animals received intragastrically extracts of black currant, medicinal raspberry, a mixture of these extracts in the ratio of 1:1 and cytochrome C, which was administered intramuscularly, for 15 days. A model of histotoxic hypoxia was used. Absolute and relative concentration of fatty acids (FA) was determined in rat brain and heart tissues.

Results. An increase in the concentration of fatty acids in all studied tissues was found in acute histotoxic hypoxia, which is an indicator of disorders of lipid and carbohydrate metabolism, which may contribute to the failure of adaptation mechanisms. Additional loading of rats with antihypoxants on the background of acute hypoxia contributed to a decrease in the concentration of fatty acids in tissues, which indicates that the studied preparations have a high lipidoprotective and antioxidant effect, and the highest efficiency is demonstrated by a mixture of extracts of medicinal raspberry and black currant in a ratio of 1:1.

Objective: to determine the characteristics of temporal variations in the dispersion mapping of ECG and HRV in cows and sport horses, as well as the early detection of possible pathological changes in cardiac activity.

Materials and methods. Cows and horses were studied in the work. The functional state of the heart of the studied animals was assessed with subsequent dispersion analysis using the CardioVisor-06s computer analyzer. The principle of operation of the device is based on the method of dispersion mapping of the electrocardiogram (ECG). The dispersion characteristics map in the CardioVisor-O6S device is projected onto the surface of a computer three-dimensional anatomical model of the heart, the so-called "heart portrait" or quasi-epicardium.

Results. The following results were obtained as a result of the research:

– a set of features of heart portrait images was proposed, allowing a more detailed description of cardiac activity in cows and horses using the CardioVisor-06S PTC;

– a method for expanding the diagnostic capabilities of the CardioVisor-06S software and hardware complex by analyzing the features of heart portrait images and identifying their characteristic values for various cardiovascular diseases is proposed;

– the use of this method is aimed at increasing the objectivity of assessing the results of analyzing an expanded set of output data obtained as a result of analyzing heart portrait images, taking into account the values of dispersion characteristics.