Many specialists in the field of biological and veterinary sciences use pure crops for work in fundamental and applied areas. The degree of purity of crops can be influenced by various factors, including violation of storage conditions. Despite the wide range of methods for the conservation of microorganisms, lyophilization and low-temperature preservation are relevant and universal for reproduction in laboratory conditions. In this regard, the department of the State Collection of Microorganisms carried out the selection of optimal methods and conditions suitable for the preservation of the strains of interest and their properties for a long time. The purpose of this work is to clarify the morphological aspect of the question of the influence of various conservation conditions on the biological properties of Bacillus anthracis vegetative and spore forms under long–term storage conditions: the ability to germinate, spore formation and morphological characteristics. A precipitated suspension of Bacillus anthracis bacterial cells of vegetative and spore forms was used as an object of research. To carry out a morphological study, B. anthracis samples were prepared using the method of ultrathin sections, contrasted and viewed under an electron beam on a transmission electron microscope. Statistical data processing was carried out in MS Excel and Statistica 6.0 programs. The nonparametric Mann–Whitney test was used, followed by correction using the Bonferroni method. According to the results of the research, it was found that the bacteria of all groups retained the ability to germinate and sporulate. The morphology of Bacillus anthracis in the State Collection of Strains generally corresponds to the data given in the literature, and storage conditions did not significantly affect these characteristics.

The aim of the present research was to study the impact of infective dose on effectiveness of levofloxacin in Antibiotic therapy solves the problems of eliminating colibacillosis, and properly constructed treatment regimens prevent the spread of resistant strains of pathogens among humans, farm animals and birds. The aim of this work was to study the effect of the infective dose of Escherichia coli on the effectiveness of levofloxacin in experimental colibacillosis of chickens. For the experiment, 375 chickens were used, which were divided into three groups of five subgroups (25 heads) in each. The birds of the first group were infected intraperitoneally with a suspension from a daily culture of E. coli at a concentration of 150 million microbial bodies / 0.5 ml (1 DLM - minimum lethal dose). Birds of the second and third groups were infected in a similar manner, with the minimum lethal dose increased to 2 DLM (300 million microbial bodies/0.5 ml of suspension) and 3 DLM (450 million microbial bodies/0.5 ml of suspension), respectively. The chickens were observed for 15 days. The efficacy of levofloxacin administered in various concentrations with drinking water was assessed by comparative analysis of the number of surviving and dead birds in the experimental and control groups. When reproducing experimental colibacillosis in chickens with an infectious dose of 1 DLM, a high therapeutic effect (100%) was achieved in the groups of birds to which the drug was administered in concentrations of 200 and 300 mg/l of water. In the groups of chickens where the infectious dose was increased to 2 DLM, the efficacy of treatment decreased to 80-84%. In groups of chickens where the challenge dose was increased to 3 DLM, treatment efficacy decreased to 64-80%.

To date, the only effective means of combating goat arthritis-encephalitis viruses (CAEV) includes its early diagnosis and slaughter of all animals in dysfunctional and suspected farms, since specific preventive measures have not been developed. Among the widely available tools for diagnostic studies, PCR indication of the CAEV genome and the detection of specific antibodies of the virus can be distinguished, which directly depends on the serological activity and specificity of the antigens used in diagnostic kits. This work is devoted to the development of a recombinant antigen for serological indication of antibodies against CAEV. As a result of bioinformatic analysis, a search was performed for amino acid sequences of virus proteins, an analysis of immunogenic epitopes of these proteins, a search for N-, O-glycosylation sites, signal peptide sites and transmembrane domains. Based on the data obtained, a recombinant multiepitope antigen was designed with the following amino acid sequence "mqktnepyedfaarlleaidaepipvgaeiipesmkylrgaksqgklneeaerwrrnnppppavraytygviempenyakvcqplvqiyrtlstptyqhhhhhh». The constructed amino acid sequence, after converting it to a nucleotide one, taking into account the codon optimization of protein production in Escherichia coli, was cloned into an expression construct based on the pET28a(+) vector. As a result of the design, the length of the created plasmid for the expression of the nucleotide sequence of the CAEV was 5527 bp. The protein developed and purified by affinity chromatography, containing amino acid sequences of immunogenic epitopes of the CAEV antigens, confirmed its functionality in indirect solid-phase enzyme immunoassay using blood sera from goats with previously confirmed immune status to this virus. The recombinant multiepitope antigen presented in this paper can be widely used as an integral component in the development of diagnostic test systems.

The aim of the study was to investigate the effect of different doses of enrofloxacin on the indices of phagocytosis of pseudoeosinophils in the blood of chickens under conditions of experimental salmonellosis. The effect of enrofloxacin in doses of 200 mg/l and 100 mg/l on the phagocytosis of pseudoeosinophils in the blood of chickens was studied. Enrofloxacin is an antibacterial drug of the fluoroquinolone group used in veterinary medicine. The use of this medicinal product is most widely represented in poultry farming, due to its excellent pharmacodynamic and antimicrobial properties. The aim of this work is to study the effect of enrofloxacin on pseudoeosinophil phagocytosis in experimental salmonellosis caused by Salmonella infantis culture. The study involved four groups consisting of day-old chicks of the Haysex Brown cross. Chickens of group I (intact control) received pure water, while in groups III and IV, enrofloxacin was drunk for 5 days with water at doses of 200 mg/l and 100 mg/l, respectively. Blood sampling was performed on the second, fourth, sixth, eighth and tenth days after drug withdrawal. Phagocytic activity, phagocytic number, phagocytic index, and phagocytic capacity of pseudoeosinophils were studied after co-incubation for 30 and 120 minutes with Staphylococcus aureus culture. The effect of enrofloxacin at a dose of 200 mg/l was manifested in a short-term increase in phagocytic activity, phagocytic index, and phagocytic capacity of pseudoeosinophils after 30 minutes of exposure. The most significant changes in phagocytic activity, phagocytic index, and phagocytic capacity of pseudoeosinophils were detected in experimentally infected groups receiving enrofloxacin at a dose of 100 mg/l, as well as pure water. All registered changes were shortlived.

Strains of Escherichia coli isolated from animals are commensal microorganisms, still some E. coli serotypes can cause pathology in animals. Accordingly new methods of treating colibacillosis are in demand. The goal of the present study was to determine the effectiveness of moxifloxacin for treatment of white mice, experimentally infected with E. coli. The drug was administered to laboratory animals intraperitoneally at a dose 20 mg per kg of body weight once a day and twice a day in the course of 1, 3, 5, 7 and 10 days. We found out that even a single administration of moxifloxacin makes it possible to achieve reliably better results, as compared to the control group. We also noted that the effectiveness of the administered drug was correspondent to the duration of treatment and the frequency of administration on days 1, 2 and 3 of the treatment. When treatment lasts one day moxifloxacin has low activity with single administration and it is active with two administrations per day. When treatment lasts 3 days the drug can be considered active with either method of administration, though the effectiveness of moxifloxacin and survivability of mice are reliably higher with 2 administrations per day. Maximum effectiveness was achieved when moxifloxacin was administered for 5, 7 and 10 days (active and highly active). Statistical analysis of the data obtained showed that frequency of administration on days 5 to 10 had little effect on the effectiveness of the drug. The differences between the respective groups were minimal and statistically unreliable. Our research demonstrated clearly the fact that in order to design new effective regimens of moxifloxacin for treating colibacillosis one must study characteristics of its pharmacokinetics.

Bovine leukemia is studied both intravitally and after slaughter of animals by different methods (serological, pathomorphological, histological, etc.). In this regard, the objective was defined: to apply RID and ELISA after slaughter of animals in diagnostics of bovine leukemia in the comparative analysis. Materials and methods: the main material for the study was 305 washings taken from carcasses and offal of animals. Of these, 185 animals were seronegative during their lifetime to BLV, and 120 heads of cattle did not undergo diagnostic tests for leukemia. The peculiarity of the methods used was that these methods (ELISA, RID) are applicable in detecting antibodies found in muscle tissue fluid (plasma, lymph) to the antigen of the bovine leukemia virus (BLV). Results of the studies: out of 185 seronegative animals tested during life, 160 heads were re-tested in RID after slaughter, and 25 were analyzed by ELISA. Both reactions (RID, ELISA) confirmed the absence of antibodies to BLV in these animals after slaughter. At the same time, diagnostic studies (ELISA and RID) were performed on swabs obtained from the carcasses (by-products) of 120 heads of cattle that were not tested for leukemia during life. Positive post-mortem results for bovine leukemia were obtained from four samples (4 (3.3%) out of 120 (homogeneous substrate)) in RID, and ELISA revealed specific antibodies to the BLV gp51 antigen in muscle tissue fluid in six (6 (5.0%) out of 120 samples) of the studied carcasses. Conclusion: the use of the ELISA method allowed us to identify two additional positive samples for bovine leukemia, which exceeds the sensitivity of the RID by 33.3%. The obtained data indicate a higher sensitivity of the ELISA method in identifying animals infected with BLV.

Mass lesions of the respiratory system of cattle represent a significant problem for livestock production not only in the Russian Federation, but also worldwide. Economic losses of livestock farms during an outbreak of bronchopneumonia of infectious etiology are associated with treatment costs and costs associated with increased mortality, premature culling of animals. Thus, timely treatment measures play a significant role in antiepizootic measures. Since the effectiveness of treatment of animals with infectious disease significantly depends on the sensitivity of the pathogen to antibacterial drugs, early inclusion of the optimal drug in the scheme of therapeutic measures allows to reduce losses. Nasopharyngeal mucus was sampled from calves of cattle breeding complex of the Leningrad region in order to isolate microorganisms associated with respiratory system lesions. Identification of isolates was carried out using culture and biochemical methods. Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Comamonas kerstersii, Escherichia coli, Moraxella bovoculi, Mannheimia haemolytica, Clostridium sp., Acinetobacter baumannii were isolated exclusively from biological material of animals with respiratory system lesions. As a result of this work the pathogens of bronchopneumonia were also deposited for further studies using phagotherapy.

The article presents the results of studies of cats with panleukopenia conducted at the Department of Epizootology and Organization of Veterinary Medicine of the Federal State Budgetary Educational Institution of Higher Education "Moscow State Academy of Veterinary Medicine and Biotechnology named after K.I. Scriabin" and at the "Zoomedic" Veterinary Clinic in Moscow. The aim of the study was to introduce automated SAPS scoring methods to predict the outcome of the disease based on the detection of hematological and biochemical changes in the blood of diseased cats. For the study, observations and assessment of physiological and biochemical changes were carried out based on laboratory data from cats with pancreas (n=10). The diagnosis was made comprehensively, taking into account anamnestic, clinical and laboratory data (PCR tests for the presence of panleukopenia virus). Panleukopenia can often lead to complications and death of animals, therefore, timely prediction of possible septic processes based on various data at an early stage is relevant. Clinically healthy animals (n=10) were used as a comparison group. Violation of the adequate response of the immune system to pathogens leads to multi factorial pathological changes in the animal's body and is accompanied by fever and depression, as well as changes in the function of blood cells, such as a decrease in platelet count, erythrocytopenia, changes in hematocrit and leukoformula, which is associated with the development of an inflammatory reaction. When assessing the biochemical parameters of blood serum, we found an increase in alanine and aspartate aminotransferase, alkaline phosphatase, and changes in urea and bilirubin levels associated with inflammation, intoxication, and dehydration. The pathogenesis is based on the imbalance between intense inflammation and immune response. The development of secondary immunodeficiency leads to various abnormalities. Correlation and regression analysis confirmed the reliability and significance of SAPS scores. A direct correlation was found between the studied traits ("Total SAPS scale score – disease outcome"), and the relationship between them was statistically significant (P=0.046075). The lethality of cats in our study amounted to 40%.

Infectious mastitis in lactating cows is a common disease causing significant economic damage. When studying the problem of infectious mastitis, the greatest interest is in assessing changes in the immunological parameters of milk and blood of cows during the occurrence and development of the inflammatory process in the udder, which is necessary to predict the further course of the disease. Timely diagnosis and prediction of the course of the inflammatory process during infectious mastitis can significantly reduce the economic damage caused. The purpose of the study is to study interleukin 1ẞ and interleukin 10 and their ratio as diagnostic biomarkers for assessing the severity of infectious mastitis. Analysis of the literature data and the data we obtained during the study revealed that the concentration of interleukin 1ẞ and interleukin 10 in cow's milk can serve as a biomarker for assessing
the severity of infectious mastitis. To conduct the research, three groups of lactating cows were formed. Each group included 4 animals, the groups were formed depending on the form of infectious mastitis - a group of healthy cows, cows with subclinical and cows with clinical purulent mastitis. The average concentrations of IL-1ẞ in the milk of cows with clinical mastitis that we obtained exceed the concentration of IL-1ẞ in the milk of healthy cows by 3.3 times, and those of cows with subclinical mastitis by 3.7 times. The concentration of IL-10 in milk of cows with subclinical mastitis is 1.2 times higher than that of healthy animals, and the level of cows with clinical mastitis is 2.7 times higher than that of cows with subclinical mastitis. For the first time, data have been obtained on the possibility of using the IL-1β/IL-10 ratio to predict the course of infectious mastitis. According to the data obtained, when the IL-1ẞ/IL-10 ratio in milk is 1.8 or more, infectious mastitis acquires a chronic relapsing course.

The aim of our study was to evaluate the microbial contamination of the air in a horse-keeping room before and after using dry salt aerosol, as well as to evaluate the dynamics of the microbial landscape in the horsekeeping room in the animal breathing zone and at different distances from the source of dry salt aerosol. To evaluate the bacterial contamination of the air when using a halogenerator, two horse-keeping rooms were organized - an experimental and a control room, each containing 4 horses, measuring 6x5x3.5, where 3.5 is the height of the room at the highest point. The room was conditionally sealed (slot losses remained) temporarily using polycarbonate window covers. Dry salt aerosol for halotherapy in horses was obtained using the Galovet halogenerator, which was used in the automatic Bronkhodzhenik mode, the session duration was 20 minutes. In the control room, the horses were not subjected to halotherapy. Visual, instrumental, microbiological, microscopic, epizootological research methods were used using generally accepted techniques. As a result of the research, it was determined that the microbial landscape of the air in the horse stable is mainly represented by Staphylococcus spp. bacteria, cocci and intestinal bacteria, mold fungi and transitional microorganisms (Nocardia spp.). In the dynamics of the use of haloaerosol, the growth of microorganisms on nutrient media was uneven in the experiment and control. A significant decrease in the concentration of staphylococci and intestinal bacteria in the respiratory zone of animals was noted. The decrease in the growth of staphylococci and intestinal bacteria at points as far away as possible from the operating halogenerator was insignificant or was not observed at the end of the session. Thus, halotherapy helps to reduce the microbial contamination of the air at a distance of at least 1.5 m from the location of the source of dry salt aerosol - the halogenerator. This effect remained pronounced 30 minutes after the end of the session. Based on the physical properties of the active dry highly dispersed sodium chloride aerosol, it can be argued that the process of its impact on microbial cells is accompanied by dehydration of the latter and an increase in their hydrophobic properties.

In European countries and in Russia until the second half of the 20th century, horses (in Spain also donkeys and mules) were not only the main labor force, but also a necessary link for ensuring transportation and waging wars. The sources on veterinary medicine of the 17th century that we studied mention equine rabies, present the main theories of its origin and spread, as well as several treatment options. These data allow us to evaluate the ideas of that time about the origin, development and spread of rabies among horses and some other animals. The aim of our study was to identify ideas about the origin and spread of rabies, in particular in horses, as well as about the methods of its treatment and control in 17th century printed sources in English, Spanish and Latin. We found that in all the sources studied, separate chapters are devoted to rabies, which describe a clinical picture that is really very similar to rabies. We also found that the main causes of rabies were indeed considered to be "poisonous saliva", which was transmitted by bites, and then affected the "humors" in such a way that the animal began to "go crazy". Due to the lack of much knowledge about the etiology, pathogenesis and outcome of the disease available to us now, in the 17th century in Spanish, Latin and English-speaking countries, horses were being treated for rabies, which undoubtedly should have led to infection of humans and other animals.

The article presents the results of a parasitological study of scrapings from the skin of the inner surface of the auricle, scalp, back, side surfaces, front and hind limbs, hair with epidermal scales of the corpse of Arctic fox puppy (Vulpes lagopus semenovi Ognev) at the age of 3-4 months, delivered from Medny Island, which is part of the Commander Islands (Russia). At the Department of Parasitology named after V.L. Yakimov of the St. Petersburg State University of Veterinary Medicine biological material was placed in 50% glycerin and examined by light microscopy using a Primo Star Zeizz microscope (Germany) under magnification of 40 and 100. Microscopy revealed acariform mites in all phases of development: egg, larvae, nymphs and adults. According to morphological features, such as: body shape, limb length, location of ambulacres on them, structure of the gnatosome, ticks are identified to the genus Otodectes. Microscopy of scrapings from the scalp, back, lateral surfaces, front and hind limbs of the arctic fox and wool with epidermal scales revealed ticks with morphological features characteristic of the genus. Otodectes. In the scrapings in the field of view at 40-fold magnification, the number of ticks ranged from 12 to 20 and indicated a high intensity of invasion. Since skin-eating ticks, including otodectes, have high specificity for the localization site, therefore, the detection of ticks of the genus. Otodectes in places of localization not specific to them is interesting in order to study their species affiliation. The purpose of further research will be a genetic analysis of ticks found on the surface of the arctic fox body to confirm the validity of the species parasitizing in carnivores - O.cynotis.

Trichinellosis is a parasitic disease caused by the introduction of Trichinella larvae into the body. Humans become infected by eating animal meat infected with Trichinella larvae. For the population of the Far Eastern Federal District, one of the main sources of invasion is the brown bear. The aim of the study was to determine the extensiveness and intensity of invasion (EI, II), as well as to study the morphological parameters of the capsules of brown bear Trichinella larvae (Ursus arctos) in the Amur Region. An analysis of official statistics from the Veterinary Department of the Amur Region and the State Budgetary Institution JSC Amur Regional Veterinary Laboratory for the period 2019-2023 showed that wild animals infected with trichinellosis were brown bear, wild boar and badger. The FSBSI FEzRVI conducted its own studies to study the infection of brown bears with Trichinella larvae. The EI, II, and capsule shape index of Trichinella larvae were determined. Morphological measurements of Trichinella larval capsules were performed using an ocular micrometer, measured in micrometers. Using compressor microscopy and digestion in IZHS, infection of a brown bear in the Amur Region was revealed with the EI of 12.5% and II of 84.7 lic/g, with p<0.05. The morphological indices of the capsules and larvae are as follows: capsule length 425.7±7.49 μm, width 388.4±3.81 μm, lateral capsule thickness 39.2±1.69 μm, poles 44.8±2.68 μm, Trichinella larval thickness 40.5±1.45 μm, with each index being reliable at p<0.05. The capsule shape index of Trichinella larvae was 0.91 µm (round shape). The EI and II indices of the brown bear indicate a focus of natural trichinellosis in the Amur Region. The morphological values of the capsule shape of Trichinella larvae in the brown bear of the Amur Region can be used to study the period of infection of animals.

The article presents the results of the pathological examination of the corpse of an arctic fox delivered from Copper Island (Commander Islands). Due to the sharp depression of the unique population of the Mednovsky (commander) Arctic fox – the only predator of Medny Island and the key element of the local ecosystem, the preservation of this subspecies is an urgent task for researchers. Parasitic diseases are widespread in arctic foxes and researchers consider arctic fox helminthiasis as one of the possible limiting factors in population depression. In this connection, the purpose of our study was to analyze pathological changes in organs and tissues, including parasitological research, which entailed the cause of death of the animal. The work was carried out at the departments of pathological anatomy and forensic veterinary medicine, pathological physiology and parasitology named after V.L. Yakimov FSBEI HE SPbGUVM. According to the results of the postmortem autopsy of the animal, signs of alimentary dystrophy, as well as acute catarrhal erosive gastritis with hemorrhage to the stomach cavity were found. According to the results of parasitological research, 11 adult nematodes of red color, 40–60 mm long, were found in the tumor-like granuloma of the gastric wall and in its cavity. Morphological data and localization of nematodes gave reason to identify them up to the river. Spirocerca. Previously, about the finds of helminths p. Spirocerca in arctic foxes Copper Island did not communicate.

This work presents the results of the study of mature individuals of Arctic char (Salvelinus alpinus L.) from Lake Ulu located in the Oymyakon district of the Republic of Sakha (Yakutia). The study was conducted as a result of control catching; fifty-two individuals of Arctic char were caught. The following parameters were measured for each fish: standard length (SL), body weight, fish age by scales and otoliths. The maturity state of the gonads and intestinal contents were also assessed. Microscopic parasites were counted by microscopic examination of a series of compression preparations of biomaterial in transmitted light using a Bressr LSd5-005 microscope (Bresser Ltd, China). The number of macroscopic parasites of each species found in each individual was recorded. Measurement of size and weight parameters and ichthyopathological examination of the char revealed a significant parasitic load that negatively affects the growth rate and the state of the population of this fish species. Less than half (42.8%) of the examined fish were free of parasites. The parasitocenosis was represented by two nematode species (Cystidicola farionis, Raphidascaris acus), a cestode (Proteocephalus thymalli) and an acanthocephalan (Neoechinorhynchus salmonis). The highest number of parasites was found in the gastrointestinal tract of the examined fish. Hematological parameters of the blood of fish without invasion and invaded individuals demonstrated reliable (p <0.05) differences in the occurrence of lymphocytes (decrease in invaded individuals), neutrophils (increase to 16.9±2.0% in invaded) and basophils (increase to 1.9% in invaded). The obtained results of diagnostics and parasitological state of the char population, characterized by low growth rate and low occurrence of older age groups, indicate the possibility of increasing fish productivity of the reservoir by suppressing parasite fauna.

A significant problem of modern industrial pig farming is the birth of a significant number of piglets with low live weight. A major problem is the further preservation and viability of physiologically immature piglets. The article describes the results of studies aimed at evaluating the effect of a stimulating drug based on recombinant cytokines of the first and second types (interferon alpha and interferon gamma), as well as vitamins A, E, and C – the drug Prostimuli – on the formation of the intestinal microbiome, as well as the mitotic activity of cells in the small intestine of piglets with perinatal hypotrophy. The experiment used newborn piglets, which were divided into 3 groups: group 1 — healthy piglets (n=10); group 2 — hypotrophic piglets (n=10), which per os, in addition to the main colostrum ration, were given cow colostrum at a dosage of 2.5 ml per head for 3 days (the scheme used in agriculture); group 3 — hypotrophic piglets (n=10), which were given parenteral Prostimul twice, in the first and third days of life at a dose of 0.1 ml / kg of body weight. On the 7th day of the piglets' life, fecal samples and small intestine samples were taken for research. According to the results of the conducted studies, it was found that the use of the drug Prostimul in piglets with perinatal hypotrophy contributes to the normalization of intestinal microflora due to the action of interferon alpha on pathogenic microorganisms, which can be used as a means of preventing colibacteriosis, and also allows to stimulate morphogenesis in the small intestine and, consequently, activate the processes of nutrient absorption, which stimulates more active growth of piglets.- hypotrophics.

The impact of chronic stress on the body of a highly productive animal has a negative effect, which is usually expressed in a decrease in productivity. A promising method for reducing chronic stress in animals are natural adaptogens, which include antlers. The aim of the work was to evaluate the effectiveness of using a dietary supplement made from European red deer antlers on the level of adaptation in Holstein-Friesian cows under chronic stress at a dairy complex. The studies were conducted from 2022 to 2023. The objects of the study were Holstein-Friesian cows that showed signs of chronic stress. The study animals were given freezedried powder from European red deer antlers. Using the pair-analogue method, a control (n = 10) and experimental (n = 10) groups were formed. The effectiveness of the supplement was assessed by a leukogram. Blood samples for analysis were taken from the tail vein on the 1st, 30th and 40th days of the experiment. Morphological blood analysis was performed using the Abaxis HM5 automatic veterinary hematology analyzer. At the beginning of the experiment, animals showed neutrophilia and eosinopenia, indicating chronic stress in animals. The powder was administered individually orally at 10 grams once a day for 30 days. The study showed a 33.7% decrease in segmented neutrophils compared to the control group, in which the corresponding indicators remained virtually unchanged and tended to increase dynamically. By the end of the experiment, the eosinophil volume in the experimental group was more than 2 times higher than in the control group. The results obtained allowed us to conclude that the antler powder is effective in reducing stress and anxiety in animals.

Currently, an important task is to improve the quality of livestock products. In this context, special attention is paid to the analysis of the biological value of meat products, which directly depends on the composition of protein components. Thus, the purpose of our study was to evaluate the effect of fulvohumate on the amino acid composition of muscle tissue of broiler chickens. It was found that the administration of fulvohumate led to a change in the amino acid composition of muscle tissue. When assessing the profile of essential amino acids, it was revealed that the introduction of fulvohumate led to a statistically significant increase in the amount of leucine and isoleucine by 4.35% (P≤0.05), valine by 5.19% (P≤0.05), lysine by 5, 15% (P≤0.05), phenylalanine by 4.23% (P≤0.05). The studied supplement led to an increase in the amount of essential amino acids by 3.55% (P≤0.05) compared to the control group. The introduction of fulvohumate provides an increase in histidine by 6.91% (P≤0.01) and arginine by 5.68% (P≤0.01) in comparison with the main diet group. During the study, an amino acid score was established, indicating the effect of fulvohumate on the biological value of the analyzed muscle tissue. The introduction of the supplement contributed to an increase in the rate of phenylalanine by 4.23% (P≤0.05) and the rate of other essential amino acids, such as: leucine + isoleucine by 4.35% (P≤0.05), valine by 5.19(P P≤0.05), lysine by 5.15% (P≤0.05), histidine by 6.91% (P≤0.01) in comparison with the main diet group. Thus, these results can be used to optimize animal feeding aimed at improving the quality of livestock products. The introduction of fulvohumate into the diet of broiler chickens helps improve the amino acid composition of muscle tissue, which increases its biological value and can lead to improved quality of meat products.

Pork is one of the key elements of the human "meat diet" and is produced in increasing volumes both in Russia and worldwide. Data on global pork production (WP), in particular for 2022–2023, according to FAO (FAOSTAT 122.989–124.668 million tons) and the US Department of Agriculture (USDA 114.62–116.30 million tons) estimates differ significantly, as do many other countries, with the exception of the USA. For example, pork production in China, which accounts for almost half of the worlds, for 2022–2023 is estimated at 56.340–58.867 million tons (FAOSTAT) and 55.410–56.500 million tons (USDA). A detailed assessment of such data for the top ten countries in the world is the main objective of this review. It is important not only that Russia today shares 3rd and 4th places in the world in pork production with Brazil, but also that Russia's share in the global pork production volume is constantly increasing (from 3.2% to 3.8% from 2018 to 2023), which indicates that pork production in the Russian Federation is growing faster than global growth. This growth, both in the number of pigs and in the production of products in the Russian Federation, is mainly (92%) provided by "agricultural organizations", and the share of farms (peasant) and the population in total amounts to no more than 8% (ROSSTAT) in recent years. Thus, in 2023, "... production in agricultural organizations, according to preliminary estimates, increased by 6.1% ..." (Ministry of Agriculture of the Russian Federation). This significant growth in pork production is one of the main drivers determining the positive dynamics in all domestic animal husbandry.

The introduction of urea (carbamide) into the composition of raw cow's milk artificially increases the protein level, which is a key parameter for evaluating product quality. However, traditional methods of analysis based on the measurement of nitrogenous compounds do not allow to distinguish natural protein from added urea, which creates a risk of falsification. To detect urea, the colorimetric method is used, regulated by GOST R 55282-2012, and according to GOST R 52054-2023, the maximum urea content in milk is established. Despite its accuracy, this technique requires significant time and labor costs. The research was conducted in stages on the basis of the Educational and Research Center for Food and Animal Feed Expertise of the St. Petersburg State University of Veterinary Medicine. Samples of raw milk without urea and with its addition in various concentrations, as well as a standardized urea sample, were used as objects of analysis. At the first stages, the IR spectra of the samples were studied, after which the dependence of the intensity of absorption peaks on the concentration of urea was analyzed. The aim of the work was to evaluate the possibility of using IR spectrometry in the medium range to identify carbamide in milk. As a result of the research, a correlation was found between the level of urea and the characteristics of the IR spectra. The most significant result was the detection of a specific absorption band unique to urea. This allows not only to quantify its impurity, but also to confirm its presence even at low concentrations.

The article presents the results of the effect of silver nanocomposite on growth and blood parameters of carp. During eight weeks fish of experimental groups received Ag-C in doses of 0.1 ppm and 0.8 ppm as a feed additive to the main diet. Silver nanocomposite had a negative effect on the growth of juvenile carp. By the end of the experiment, Group I, which received Ag-C nanocomposite at a dosage of 0.1 ppm, was 48.9 % behind the control group in growth, and Group II, which received Ag-C nanocomposite at a dosage of 0.8 ppm, was 12.7 % behind the control group in growth. Decrease in the number of leukocytes and increase in the number of erythrocytes, hemoglobin, hematocrit, thrombocytes in group I indicates an increase in metabolic processes and redox reactions, antibacterial effect of silver, as well as indicates the stress response of the body to toxic exposure. The levels of urea, creatinine and uric acid significantly exceeded the control values in the experimental groups, which is associated with the activation of the processes of reducing the toxic effect of silver on the body of carp. The antibacterial and toxic effect of silver can be seen from the blood parameters in our study. Eliminating pathogenic microflora in the body, Ag-C nanocomposite also had a strong toxic effect

Mycotoxins (metabolites of toxigenic isolates of microscopic fungi) are ubiquitous in animal feed and food raw materials. To register feed additives, a specific package of documents is generated, which constitute a registration dossier, which includes an assessment of the results of toxicological studies and safety of use, as well as the preservation of the declared chemical-physical, microbiological and biological properties within certain limits during the established shelf life (i.e. stability study). The purpose of the research is to assess the stability of the complex feed additive "Galluasorb" based on the natural nanomaterial halloysite, glucans of plant origin, methionine, milk thistle meal. Testing of 3 batches of the feed additive "Galluasorb" for compliance with the requirements of technical specifications TU 10.91.10-008-00492374-2024 was carried out at the beginning of storage and after 3, 6, 9 and 12 months. The tests were carried out on samples of the feed additive packaged in kraft paper bags with a rectangular bottom with a volume of 1 dm3, which were stored in a dry room, excluding exposure to light, at a temperature of no more than +25 °C and a humidity of no more than 60%. During storage, the quality (appearance, mass fraction of moisture and ash) and safety (toxicity, content of pathogenic microorganisms and toxic elements) and authenticity indicators were assessed. As a result of the experiment, it was established that during 12 months of storage, Galluasorb complies with the requirements of technical conditions in terms of quality and safety indicators. When the storage conditions are observed, the stability of the declared quality indicators is preserved. An increase in the humidity of the adsorbent was recorded, not exceeding the established standard. Changes in the physicochemical properties were also not recorded when exposed to a temperature of 115 °C for 10 minutes.

Currently, in addition to traditional methods in poultry farming, they have begun to use wave technologies based on the effect of weak electromagnetic fields on birds. Studies were carried out on 80 broiler chickens of the cross “Change 9” in the educational and production poultry house and laboratory of nutritional physiology of K.A. Timiryazev Russian State Academy of Agriculture named after K.A. Timiryazev in 2024. Physiological status and zootechnical indicators of poultry were studied under heat stress conditions. Non-invasive electromagnetic therapy device “TOR” (manufacturer “Concern GRANIT” JSC) was used as a method to increase metabolism and productivity. The results of research showed that the live weight gain for the period of experience (35 days) in broiler chickens of the experimental group was higher by 19.5% (p<0.05), which can be explained by a higher metabolism in the body of experimental chickens, because they significantly increased feed intake (by 7.3%). Nutrient assimilation was higher as the cost per 1 kg of live weight gain in the experimental group was lower by 10.2% compared to the control group. This was due to the strengthening of digestive processes, with trypsin activity increasing in the experimental group by 24.4% (p<0,05) compared to the control group. Trypsin activity in blood serum tended to increase by 10.9%, total protein increased by 8.9% (p<0,05), indicating an increase in the rate of protein metabolism towards assimilation. Consequently, the multifaceted role of trypsin in the organism can fulfill the role of a biomarker in diagnosing the stress state of the animal organism and can be corrected using different methods, including electromagnetic radiation.

Modern technologies open up prospects for using new effective methods of stimulating reparative osteogenesis in order to optimize patient treatment outcomes. The aim of the study was to present microscopic and biomechanical characteristics of rat diaphysis and femoral bone regeneration formed on the 120th day after surgery and the use of MMSC secretome. The results of experimental study of structural and biomechanical characteristics of rat femoral diaphysis regenerate on the 120th day of reparative osteogenesis after induction of bone defect under the conditions of application of an innovative regenerative preparation - secretome of multipotent mesenchymal stromal cells – are presented. Bone samples in which saline solution was injected into the area of osteorepair, as well as intact rat femurs served as control. The material was studied by light microscopy, microscopic morphometry and biomechanical tests. It was found that in the experimental group the regenerate is compacted, has histotypic features and is formed mainly by lamellar bone tissue. In the control group, the regenerate is thinner than in the experimental group, has no histotypic features, and in its structure, there is a greater representation of reticulofibrous bone tissue compared to the experimental group. Both in the experimental and control groups the remodeling of the regenerate is not completed. Obviously, this affects the strength characteristics of the bone. Biomechanical tests have shown that the femur bones of animals of the experimental and control groups are inferior to intact samples in terms of strength characteristics. At the same time, experimental samples exceed control samples by 25%, which corresponds to the results of morphological studies.

The article presents micromorphological features of the pulp chamber wall of a tooth and its structural elements in a dog. The study was carried out on the basis of the Department of Animal Diseases and Veterinary and Sanitary Examination of the Federal State Budgetary Educational Institution of Higher Professional Education Vavilov University and the Department of Anatomy and Histology of Animals named after Prof. A.F. Klimov, Moscow State Academy of Veterinary Medicine and Biotechnology – MVA by K.I. Skryabin. The object of the study was mesocephalic dogs (n=15) aged from 2 to 3 years. The incisor group of teeth (n=15) served as the material for the study. Microscopic examination and micromorphometry were performed on a digital microscope LEICA LMD 7000 (Germany). Based on the results of the study, it was found that the pulp cavity wall was formed by intertubular dentin with the ends of dentin tubes protruding above it. This type of dentin is represented by a homogeneous mass of gray color, while the protruding ends of its tubes have different length, diameter and various bends. The study of the wall part of dentin showed an increase in the length of its tubules with a simultaneous decrease in their diameter. It is revealed that due to various bends of tubules on the surface of intratubular dentin they acquire a fragmentary appearance. In deeper layers of dentin, compared to the surface of the pulp chamber, the predominance of intratubular dentin is noted, which leads to a wider arrangement of dentinal tubules between each other.

Despite the development and modernization of agriculture, mycotoxicosis remains one of the important problems of poultry farming. Due to the production of several mycotoxins by mold fungi at once, it is important to talk about their combined action, which, due to the synergistic effect, can cause more serious changes in the body than each individual toxin. Pathological changes primarily occur in the liver and other target organs. It is known that drugs that have a targeted effect on hepatocytes are promising as therapeutic and prophylactic agents against mycotoxicosis. The objective of this work is to evaluate the hepatoprotective activity of the complex adsorbent "Galluasorb" at the ultrastructural level in experimental combined mycotoxicosis of broiler chickens. The experiment was conducted on 40 broiler chickens of the СOBB-500 cross, aged 21-22 days, divided into four groups: group 1 (BC) - biological control; group 2 (TC) – toxic control (toxic diet contaminated with T -2 toxin, aflatoxin B1 and zearalenone); group 3 (TC+GS) – preventive (toxic diet with the addition of 0.25% Galluasorb); group 4 (BC+GS) – safety control (regular diet with 0.25% Galluasorb). For morphological examination, 1 mm3 liver pieces were prepared using the ultrathin section technique, contrasted and examined on TEM. Then, the obtained electronograms were described and morphometry was performed, taking into account the following mitochondria characteristics: area, perimeter, caliperometric diameter (Feret diameter), roundness coefficient. Statistical data processing was performed using descriptive and comparative statistics (nonparametric Mann-Whitney test, α=0.05; Bonferroni correction p). Based on the research results, a protective effect of the Galluasorb adsorbent was revealed in relation to the general cytomorphology of hepatocytes and morphometric indices of mitochondria of hepatocytes in broiler chickens.

Service dogs in the Russian Federation play the most important role in the executive authorities, performing complex tasks in which these trained animals are indispensable to this day. The most common service dog breeds on the territory of the Russian Federation participating in search, patrol, search, special, escort and guard activities are the German Shepherd, Belgian Shepherd, Spaniel, Labrador. Dysplasia of the elbow joint and injury with high-energy injuries, often has only surgical methods of treatment in dogs, it is necessary to develop the safest, most effective surgical approaches to the elbow joint with anatomical and topographic justification. The study was conducted in the network of veterinary centers "Kotonai" in St. Petersburg. The object of the study was dogs of the Labrador breed in the amount of 10 individuals. Research methods: morphometry, computed tomography. As a result of the study, it was found that the humerus has the lowest growth potential in the first age group, however, it has the largest area of epiphyseal zones, which may affect the planning of surgical interventions in the area of the elbow joint, as well as in the treatment of epiphysiolysis of the humerus. Evaluation of ossification of the processes of the ulna by computed tomography in case of suspected dysplastic changes in the type of disease of the medial coronary process and non-fusion of the hooked process is possible at the age of 5.5 months in Labrador dogs. To obtain more accurate data on the comparative anatomy of the bones forming the elbow joint, the study of this topic should be continued, and to reduce measurement errors, studies should be conducted on groups according to the sex of the animal.

Morphometric studies of the skull in dogs are mainly aimed at studying the relationship between the facial and cerebral divisions in different breeds of dogs, their morphotyping and analysis of the skull as a whole, without taking into account the characteristics of the cranial cavity parameters. In dogs of brachycephalic breeds, these studies are of particular value in view of their tendency to impaired cerebral circulation and increased intracranial pressure due to the structural features of the skull. The purpose of the study is to provide a morphometric characterization of the cranial cavity of brachycephalic breed dogs. The research method is computed tomography, French Bulldog dogs were included in the group of dogs for the study. The average age of the animals included in the study was 4 years, all animals were over 2 years old and had no history of head pathology. A total of 12 dogs were examined. During morphometry, the parameters of the maximum width, height and length of the cranial cavity, similar parameters of the cerebral part of the skull, as well as the zygomatic width and total length of the skull were determined. The morphometric data obtained was used to calculate indices reflecting the relative parameters of the cranial cavity. Of the studied parameters of the cranial cavity, the largest is its length, which on average reaches a value of 6.57± 0.33 cm. The width of the cranial cavity is 1.29 times lower than the length, but 1.06 times higher than the height of the cranial cavity. The index of the cranial cavity is 77.58. of the studied parameters of the cranial region of the skull, similar to measurements of the cranial cavity, the largest is its length, which on average reaches a value of 8.63± 0.59 cm. However, the values of width and height are not directly correlated with similar indicators of the cranial cavity. The height of the cerebral region is 1.35 times less than its length and 1.15 times greater than its width. The comparison of indices reflecting the craniometric parameters of the cranial cavity and the cerebral skull is in direct correlation with the absolute values.

In the last decade, significant progress has been achieved in pork production and Russian pig farming in general. However, it is necessary to intensify work on establishing standards for the main biochemical (BC) parameters of the blood of commercial pig hybrids, which was the main goal of the work. The studies were conducted on boars of the following groups: 1) Duroc breed on the 60-65th day of fattening (n=12), 2) F2 Duroc˟Landrace˟Large White hybrids on the 60-65th day of fattening (n=19), 3) Duroc breed on the 100-110th day of fattening (n=18) and 4) F2 Duroc˟Landrace˟Large White hybrids on the 100-110th day of fattening (n=27). Blood samples were taken from the ear vein into vacuum tubes with a blood coagulation activator for biochemical coagulation analysis and centrifuged (15 min at 3000 rpm). Biochemical coagulation analysis was performed on a ChemWell analyzer (Awareness Technology, USA). Amino acid concentrations in blood serum were determined by ion-exchange chromatography on a HPLC LC-20 Prominence (Shimadzu, Japan) with a proprietary column and a module for post-column derivatization with ninhydrin ARM-1000 (Sevko&Co, Russia). Samples for analysis were prepared according to GOST 32195-2013. It is positive that the main protein indices of blood in Duroc pigs and their F2 hybrids in different age groups are quite stable, as evidenced by low and moderate variation coefficients (CV<20%). It is shown that with an increase in the fattening period, the tendencies to intensify all types of metabolism increase, as evidenced by numerous correlations between the biochemical and amino acid parameters of blood of boars of groups 3 and 4 at the end of fattening (100-110 days) compared to groups 1 and 2 (a period of 60-65 days). The authors believe that establishing relationships between the biochemical parameters of pig blood, on the one hand, and their breed characteristics and fattening duration, on the other hand, is of great fundamental and practical importance.

The cardiovertebral index is the most accurate system for estimating the size of the cardiac silhouette on radiographs for assessing cardiomegaly in small pets (cats and dogs). However, the study of VHS in dwarf rabbits remains insufficiently studied, currently there are no publications with indexes for minor dwarf rabbits. The article presents anatomical features of the heart and thoracic spine of ornamental rabbits. The research was conducted at the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine and the Kotonai network of veterinary centers. The X-ray images of fifty decorative rabbits of various breeds served as the material for the study. The average weight of the studied rabbits was 1.10±0.10 kg. To study the features of the anatomical boundaries of the heart on the X-ray, a comparative anatomical method was used, followed by an analysis of the data obtained in the Radiant program. As a result of the research, it was found that the thoracic spine of rabbits consists of 12 thoracic vertebrae. The thorax is the bony skeleton of the thoracic cavity, in which some tubular and parenchymal organs are located. X-ray examination allows you to take the necessary measurements and deduce the cardiovertebral index together with the Buchanan coefficient for an objective assessment of heart changes during X-ray examination. In our study, based on the linear parameters of the heart silhouette on chest X-rays in decorative rabbits, we derived and adapted the Buchanan coefficient and VHS. These indices make it possible to objectively assess the boundaries of the heart of ornamental rabbits in normal conditions, as well as to detect possible pathologies of the cardiovascular system, such as cardiomegaly.

Increasing aquaculture production is an important condition for ensuring food security in Russia and promoting socio-economic development of the regions. Parasalmo mykiss or rainbow trout is one of the most popular objects of industrial fish farming due to its commercial value and biological characteristics, including rapid growth and resistance to intensive cultivation conditions. The purpose of this study was to examine the morphological parameters of rainbow trout (Parasalmo mykiss) blood when introducing various probiotic preparations into the diet. To assess the physiological state of the fish, the following morphological parameters of blood were determined: the number of erythrocytes and leukocytes, hemoglobin concentration, hematocrit. When analyzing the data obtained from the use of the probiotic supplements Probiotic-1 and Probiotic-2 in the diet of yearling rainbow trout, it can be concluded that the average erythrocyte count of yearling trout, whose diet included the supplement Probiotic-2, is 30.7% higher than that of the group receiving the production feed without additives, and 13.74% higher than that of the group receiving the supplement Probiotic-1 with their feed. The total leukocyte count of yearling trout, whose diet included the supplement Probiotic-2, is 3.11% higher than that of the group receiving the production feed without additives, and 1.39% higher than that of the group receiving the supplement Probiotic-1. Thus, it can be concluded that the experimental probiotic preparations based on bacterial strains of the genus P. Lactobacillus on morphological parameters of rainbow trout (Parasalmo mykiss) blood. These preparations have an adaptogenic effect on the rainbow trout organism, contributing to an increase in resistance parameters. The obtained results can be used to optimize the composition of production feeds for rainbow trout and to correct the microbiome of fish of different ages.

Osteosarcoma (OS) is the most common primary malignant tumor of bone tissue in humans, laboratory animals, and domestic animals. The causes of OS remain unknown in most cases. OC can affect any part of the skeleton, but is most often localized in long bones. OS is characterized by diffuse infiltrative growth, rapid dissemination via blood vessels and the development of multiple metastases in the lungs. To reliably verify the diagnosis of OS, it is necessary to compare the results of an X-ray examination of the lesion with data obtained from a morphological examination of biopsy or surgical material obtained from tumor tissue. This article describes a rare case of spontaneously occurring OS of the proximal humerus with multiple metastatic nodes in the lungs in a mature female green monkey (Chlorocebus aethiops ssp.). A large tumor mass destroyed the cortical layer and periosteum of the humerus, grew into adjacent tissues, and multiple metastases were found in the lungs. Microscopically, the tumor was an anaplastic mesenchymal neoplasm with invasive growth and foci of ossification and the formation of neoplastic bone tissue (osteoid). Atypical cells of tumor tissue had different shapes, structures and sizes. To our knowledge, this is the first described case of OS manifestation in the appendicular skeleton in the green monkey. The occurrence of spontaneous OS in lower monkeys and the similarity of pathological changes at the macro- and microscopic levels indicates the possibility of using these animals as a natural model for studying similar pathology in
humans.

In highly productive fish farming, antibiotics are still the only way to prevent and treat infectious diseases. The use of antibiotics is not always rational, often accompanied by the formation of multiple drug resistance in pathogens, affects the ecological state of the reservoir and the safety of farmed fish products for humans. Many antibacterial drugs accumulate in individual organs and tissues and remain stable even after cooking the fish. Currently, the need for drugs with adaptogenic properties can be associated with changes in the situation on the feed additives market, a shortage of domestic effective nutraceuticals and biologically active substances, including vitamins, mineral complexes, dietary fiber, pro- and prebiotics. The aim of the study was to study the effect of various probiotic supplements in the diet of rainbow trout (Oncorhynchus mykiss) on the biochemical status of its body. Blood biochemical parameters (ALT, AST, ALP activity, total bilirubin, total protein, albumin, creatinine, urea, glucose, cholesterol) were determined using an automatic Chem Well biochemical analyzer (Awareness Technology, USA). The studies revealed that the studied probiotic preparations do not have a hepatotoxic and nephrotoxic effect, as indicated by the absence of reliable changes in biochemical parameters characterizing the functioning of the liver and kidneys, but have a positive effect on the protein metabolism of fish. Thus, we can conclude that the experimental probiotic preparations based on strains of bacteria of the genus Lactobacillus have a positive effect on the metabolism of rainbow trout. The results of the studies can also be used to optimize the composition of production feed for rainbow trout.

On the basis of complex morphological studies, a comparative characterization of light-optical, ultrastructural and morphometric parameters of superficial pectoral muscle in 35-day-old broiler chickens of meat cross Cobb-500 kept on different diets: basic and with the addition of feed additives (prebiotic, probiotic, sorbent) of domestic production is presented. It is shown that depending on the features of feeding ration in the superficial pectoral muscle varies the degree of development of muscle fibers and connective tissue component of the muscle, as well as the density of myofibrils packing and the development of mitochondrial network. Representatives of the cross Cobb-500 in the groups “Control”, “Prebiotic” and “Probiotic” have similar morphological and morphometric parameters of the superficial pectoral muscle. All three groups are characterized by dense packing of muscle fibers of the first order, which is associated with a small thickness of the endomysium. At the same time, the perimysium is well developed, which determines a rather loose arrangement of the second-order bundles. In the “Prebiotic” and “Probiotic” groups, compared to the control samples, the representation of large-diameter muscle fibers increased, which may indicate the synchronization of growth of different muscle fibers against the background of application of appropriate feed additives. In the “Sorbent” group, a pronounced decrease in the density of muscle fibers and their bundles in the muscle structure with a significant representation of connective tissue and a low content of white adipose tissue was determined. In this group, the signs that may indicate a delayed realization of growth processes in the muscle were revealed. The obtained data are expedient to be taken into account when formulating diets in industrial poultry farming. They can also be used as morphological criteria in assessing the quality of poultry meat during commodity and veterinarysanitary examination.

Increasing the productivity of farm animals without harming their health is one of the most important tasks of modern animal husbandry. One of the solutions is the use of feed additives that can compensate for the deficiency of nutrients and biologically active components that can positively affect the productivity of animals and the quality of the final product. Of particular interest in this area are fucus waters rich in iodine, microelements (selenium, zinc, iron), vitamins (A, D, E, group B), characteristic polysaccharides (fucoidans, alginates) and omega-3 fatty acids. Alginates, for example, improve the functioning of the gastrointestinal tract, and fucoids have anti-inflammatory and antioxidant effects. The use of powder based on fucus liquid is a promising direction, especially for regions with accessible raw materials, such as the Leningrad Region. The purpose of the study is to study the effect of fucus water additives on the productivity of cows and the quality of milk. During the study, we found that when using a feed additive containing fucus water, there was a sharp increase in the norm in the experimental group (by 11%), and the effectiveness in terms of milk quality was observed through a significant increase in the percentage of fat in the experimental group (by 10.8%). There was also a reliable decrease in the level of urea milk in the experimental group (by 3.4% and 7%). The results can be used in safe and applicable feed solutions to improve productivity in animal husbandry, which is especially important at present, since there is a steady trend towards increasing the level of highly productive animals, such methods often cannot be fully satisfied with standard diets.

The state programs for the development of animal husbandry aim not only to increase the dairy productivity of cows, but also to improve the quality of milk. The development of molecular genetics of farm animals has created conditions for the search for key genes, the polymorphism of which makes a significant contribution to solving the problems of practical breeding. Among the many genes that determine milk productivity and milk quality, a group of genes can be identified that make the greatest contribution to the formation and functioning of this quantitative trait. These primarily include the kappa-casein (CSN3) gene. The aim of the work was to establish the polymorphism of the kappa-casein gene in Holstein and Red steppe cows and to identify the relationship between the genotypes and the dairy productivity of animals. The object of the study was cows of two breeds: Holstein (n = 60) and Red steppe (n = 53). Animal genotyping was performed by PCR- RFLP. It was found that the heterozygous CSN3B genotype was the most common CSN3 gene in the group of Holstein cows – 46.7 %, while the homozygous CSN3AA genotype was the most common in the group of red steppe cows – 62.3 %, and the frequency of occurrence of the desired homozygous CSN3B variant was the lowest, amounting to 10.0 and 5.7 %, respectively. The best milk yield results (8810.0 kg of milk) were observed in Holstein cows carrying homozygous CSN3B genotype. In the sample of cows of the red steppe breed, the milk yield advantage was found in animals carrying homozygous CSN3AA genotype – 4200.0 kg of milk. Consequently, research shows that understanding how different genetic variants of marker genes affect milk productivity and quality will further allow us to form long-term strategies for both an individual farm and the industry as a whole.

The aim of the study was to investigate the cytokine profile of newborn calves that had undergone antenatal and intranatal hypoxia. Three groups of calves took part in the study: healthy (n = 8); those that had undergone antenatal hypoxia (n = 14); those that had undergone intranatal asphyxia (n = 12). Three days after birth, blood samples were taken from these animals to determine the concentration of interleukin-1β (IL-1β), interleukin-10 (IL-10) and interferon-γ (IFN-γ) using the enzyme immunoassay. It was found that in calves with antenatal and intranatal hypoxia, the cytokine profile is characterized by an increased level of IL-1β by 14.9-84.4% (P 0.05) and a decreased level of IL-10 produced by type II T-lymphocytes by 18.3-19.8% (P 0.05). At the same time, the amount of INF-γ produced by type I Tlymphocytes in calves with antenatal hypoxia does not change significantly, whereas in calves with intranatal hypoxia this indicator increases by 14.7% (P 0.05). When calculating IL-1β/IL-10, it was noted that in animals that have undergone antenatal and intranatal hypoxia, this indicator significantly exceeds the value of healthy animals. Thus, for the former it is higher by 43.5% (P 0.05), and for the latter by 2.3 times (P 0.05). In turn, the calculation of the INF-γ/IL-10 ratio shows that in calves that have experienced antenatal and intranatal hypoxia, this indicator is higher by 27.2 and 40.8% (P 0.05), respectively. Thus, the study showed that in newborn calves that have experienced hypoxic conditions, the activity of T-cell immunity and proinflammatory cytokine profile prevail, which reflects the severity of the pathological effect.

A large amount of data has been accumulated indicating a decrease in the effectiveness of breeding work with dairy cattle due to significant problems with reproduction. In breeding, not only the breeding method is of particular importance, but also the method of selection, on which their reproductive ability depends. The article considers the issue of the influence of the degree of inbreeding, as an extreme form of homogeneous selection, when using the method of linear breeding of cows on their reproductive qualities. The research was carried out on the livestock of 437 cows of the breed of Sychevka, which calved for the first time in the period 2013-2022 in Vostok LLC of the Smolensk region. For a retrospective analysis, the number of cows was taken, the proportion of blood in the improving Holstein breed of which does not exceed 25 %. The values of the age of the first calving, the indifference period and the service period obtained as a result of the research do not significantly depend on the degree of inbreeding applied; however, they have different indicators in the context of linear affiliation. The largest number of livestock with a high degree of inbreeding was found in the Klever 68 line (52.5 %). The breeding stock of the Aromat 3433 lines and Danzig 3641 are completely out breed. Only in the Toreador 3032 line, the livestock obtained using closely related selection has a significantly low age of the first calving (29.7 months). Throughout the studied livestock, the most precocious animals are out breeding selection. One of the lowest age of the first calving in cows from the line Anis 4593, obtained without the use of inbreeding (28.1 months). The average values of the herd's indifference period in Vostok LLC indicate that the sexual cycle of 58 % of cows resumes within 60 days after calving. The service period of animals in Vostok LLC is closest to the optimal values for cows from the Anis 4593 and Danzig 3641 lines (46–95 days) with remote inbreeding and out breeding selection. In the descendants of the Klever 68 line, with closely related selection, the longest service period exceeding 165 days was revealed in the first lactation. The share of the influence of the degree of inbreeding on the age of the first calving and the indifferent period of cows of the Sychevka breed in an agricultural enterprise does not exceed 5 %.

Insulin-like growth factor-1 (IGF-1), secreted in the liver, is one of the major elements of the somatotropic axis, is involved in numerous physiological processes, and plays a role in the control of lactation, mammary gland development, and the formation of important performance traits such as growth and reproductive traits. The associations of IGF-1 gene polymorphism (T → C 512) have been studied and evaluated with economically useful traits in different breeds of dairy and beef cattle. The study carried out on the population of Holstein cows and Holstein and Holsteinized bullssires allowed to establish that the identified populations are polymorphic, the animals are represented by three genotypes of IGF-1 gene. The frequency of occurrence of IGF-1 gene genotypes in the cow population amounted to: AA - 24.7 %, AB and BB - 55.6 and 27.3 %, and in bulls-sires: AA – 31.3 %, AB – 49.3 % and BB – 19.4 %. In both cases, the predominance of the “normal” allele over the “mutant” allele was observed, with the A allele prevailing over the B allele to a greater extent in the group of breeding bulls. The analysis of literature data indicates that the frequency of alleles (A and B) and genotypes (AA, AB and BB) in populations shows variation depending on breed, direction of productivity and habitat of cattle.

The article is devoted to the quantitative and qualitative echographic characteristics of ovarian structures in dogs during the estrus of the sexual cycle, the significance of the follicular echogenicity index in detecting ovulation. The object of the study was 27 sexually mature female dogs of different breeds, from the period of proestrus to diestrus. The animals were divided into 3 groups: the first group - dogs weighing up to 5 kg (n = 12), the second group – dogs weighing 6-20 kg (n = 8), the third group - dogs weighing more than 20 kg (n = 7). The studies were carried out at the Pirogov Veterinary Center in Stavropol on a SIUI Apogee 1100 Omni scanner (Shantou Institute of Ultrasonic Instruments Co., Ltd., Guangdong, China) according to the generally accepted technique using a multi-frequency linear sensor with a frequency of 7.5-12 MHz in B-mode. The quantitative parameters of the echogenicity of the ovaries and follicles were determined using the techniques of Silina T.L. et al. (2010) and Tsygansky R.A. (2020). Specific echographic markers of the ovulation process have been established, in the form of an increase in the hyperechoic border of follicles by 0.1-0.2 cm or loss of clarity of the follicle contour with a decrease in their size, loss of follicle symmetry, a decrease in the number of follicles by 30-40%. During estrus, the follicular echogenicity index (FEI – the ratio of quantitative units of echogenicity of the stroma and follicles). At the beginning of proestrus, this index is 1.5-1.7, by the end of proestrus 2.0-2.5, which indicates a decrease in the echogenicity of the follicles during folliculogenesis, after ovulation, this index decreased below 2.0. Dynamic changes in the echographic parameters of the ovaries were accompanied by an increase in the concentration of progesterone in the blood serum of dogs. The obtained qualitative and quantitative sonographic data of the ovaries of dogs in the process of folliculogenesis can serve as a basis for identifying various stages of the active phase of the sexual cycle during ultrasound examination.

Dogs with fractures of the ischial bones can be subjected to both – conservative treatment, in case of stable fractures, and operative treatment, in case of instable fractures. The techniques of fixation of the ischial bone fragments using epibone plates, rods, (drill) wires and wire are sufficiently wellknown. The aim of this research Is to estimate the surgical treatment of dogs with instable fractures of the ischial bone using the technique of intercortical and transosseous introduction of wires and subsequent fixation with an external construct. The case reports and X-rays of 400 dogs with pelvic injuries were studied. Conservative treatment was performed in 280 dogs and surgical – in 120 ones. Ischial bone fractures made up 33% of all pelvic injuries, and were revealed in 74% dogs. There were found two of the most often noted combinations of pelvic injuries which included the ischial bone. Fixation of the fragments of the body of ischial bone was performed using a wire introduced inraosseously from the caudal end of the ischial bone plate along the pelvic bone axis together with transosseous osteosynthesis of pelvic bones and articulations using a device of external fixation. The intercortical introduction of wires in case of ischium body fractures in different combinations of pelvic injuries was made in 63 dogs or in 52% cases of surgical treatment. The periods of union of ischial bone fractures were in adult dogs 60±10 days on the average, in young dogs under one year – 30±10 days. The review of literature and the analysis of clinical results for instable ischial fractures demonstrated the validity of surgical treatment. The use of little-invasive surgical approach to the ischial body during reposition, and intraosseous fixation of fragments using an intercortically introduced wire simultaneously with rigid external fixation allows to achieve anatomic and stable alignment and according good results of repairing both ischium in particular, and pelvis on the whole.

Healthy hooves are essential for the normal life of the horse, they carry the weight of the animal and cushion the impact force of each movement, protecting the joints from damage. Under load, the hoof increases blood flow to the limb. Hoof problems can lead to lameness causing discomfort to the horse and potentially leading to withdrawal from training. There are various methods for assessing hoof health. In veterinary practice, radiography, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) are widely used. All of these methods require special and expensive equipment, as well as physical manipulation of horses. Thermography is a non-invasive diagnostic technique that involves scanning the animal's surface temperature to look for areas representing potential vascular changes. Because thermography is non-invasive and inexpensive, it can be used to detect early changes before lameness occurs. Fifteen healthy horses and 15 horses diagnosed with arrowroot rot were selected for the study in 2024 under the conditions of equestrian complexes in St. Petersburg and the Leningrad region. A thermographic study of hoof temperature with healthy arrowroot and hooves with arrowroot thrush was carried out. Analyses were made based on the studies. The study showed that in healthy animals there were no significant differences between paired hooves, while in animals with arrowhead thrush there was a difference in temperature. Comparison of groups using nonparametric Mann-Whitney test showed statistically significant deviation of temperature from the plantar surface in the area of the arrow in animals with arrow lesions.

The aim of the work was to determine the therapeutic and preventive and economic efficiency of using the "SV" product for dry hoof baths developed by the staff of the Federal State Budgetary Institution “FCTRBVNIVI” in the conditions of an agricultural enterprise unfavorable for diseases of fingers and hooves. With the course use of such baths for 20 days, the number of lame cows in the experimental group decreased by 69.57%, in the comparison group, where baths were carried out using a 10% solution of copper sulfate - by 34.78%, while in the control (intact) group the number of lame cows increased by 45.83%. The damage from diseases of the fingers and hooves was also calculated based on such indicators as: lost milk, decreased live weight and premature culling of animals, decreased offspring yield, increased service period, which significantly hinder the receipt of greater profit and the effectiveness of the production activities of the agricultural enterprise. The effectiveness of the measures taken against these diseases was determined during a comparative test of traditional "wet" and baths with the product developed by us. At the same time, the economic damage from diseases of the fingers and hooves, and the costs of veterinary measures using the "SV" product were minimal, and the economic effect was maximum. The economic efficiency of using "SV" was 2.2 rubles per ruble of costs. Savings in material costs when using the "SV" product in the experimental group compared to using a 10% solution of copper sulfate amounted to 856,000 rub. Thus, the developed product made it possible to improve the health of the experimental livestock in a short time with minimal costs. The results of the research, allowed the management of the agricultural enterprise to see the problem in more detail and in the future to make timely decisions on preventing, eliminating and (or) minimizing damage from diseases of the fingers and hooves of cattle.

The aim of the study was to compare the effectiveness of different ointments in the local treatment of ulcerative lesions in the distal extremities of dairy cows. The studies were conducted from January to December 2023. based on the Kupinskoye State Unitary Enterprise (now Kupinskoye JSC) Bezenchuk district of the Samara region. The object of the study was animals of the Holstein breed, numbering about 1,850 heads, 800 of them dairy cows. The cows were 3-8 years old and had a live weight of 550-600 kg. To study the effect of ointment bases on the healing processes of crumb ulcers on the hooves of cows, three groups of ten animals each were formed, a control group and two experimental ones, in the control group ointments "Ungula Vita+)" were applied topically, in the experimental group ointments developed by us: "Vet-Kopin" and "VetKopem". Clinical studies have shown that the studied ointment preparations have different therapeutic effects in the treatment of crumb ulcers. The most effective ointment was "Vet-Kopin", used in the first experimental group, its use reduced the duration of treatment by 1.4 days compared to the second group, and 3.3 days for the control group. It was revealed that the highest percentage of healing to the initial area of ulcerative defects was on the 3rd day in all groups, in the control group - 64.48, in the first experimental group – 55.69, in the second – 56.87%. The lowest percentage of ulcerative defect to the initial area was in the control and second experimental groups on day 10 – 8.28 and 3.71%, and in the first experimental group on the seventh day – 14.36.

A methodology was developed to create a customized guide for Cranial Closing Wedge Osteotomy (CCWO) in dogs using additive technology. The study included a comparative evaluation of the accuracy of tibial angle correction and the duration of surgery with and without a customized osteotomy guide. The pelvic limbs of six cadaver dogs of different breeds and weight categories were used in the experiment. Postoperative Tibial Plate Angle (TPA) and mechanical medial proximal tibial plate angle (mMPTA) were analyzed in both groups to evaluate the effectiveness of the method. In the group with a guide, the mean difference between expected and postoperative TPA and mMPTA angles was 0.58±0.28° and 0.21±0.06°, whereas these values were significantly higher in the group without a guide, 0.99±0.79° and 1.13±0.50°, respectively. In addition, the use of a customized guidewire significantly shortened the duration of surgical intervention. The average time of CCWO surgery with the use of the guidewire was 29.83±4.98 min, which is 64.56% less than that of classical CCWO without the guidewire (84.17±12.97 min). The developed method allows to perform precision planning of osteotomy, providing high accuracy of surgical intervention and significantly reducing the operation time. The introduction of individual guidewires based on 3D modeling and printing contributes to the optimization of the CCWO technique and can improve the efficiency of treatment of dogs with excessive tibial plateau inclination angle.

The article proposes a new comprehensive method for assessing the problematic behavior of companion dogs. The aim of the study is to develop a system for the comprehensive analysis of dog behavior using behavioral markers, blank tests, wearable devices and neural networks. The method involves the sequential execution of a series of test samples and blank tests. To test and implement the method in accordance with the "Open Field Test" paradigm, a landfill has been prepared, within which, using two analog video cameras and a wearable accelerometer, the free behavior of a dog at the landfill is recorded as part of a series of experimental tests. The tests included familiarization with the training ground, typical behavior for this dog when interacting with the owner and a stranger, being alone, reactions to loud and quiet sounds, and ECG recording. Putting on an accelerometer and the dog's reaction to a thermal imaging camera were used as separate small tests. The owners separately filled out questionnaire blank tests to analyze the anamnesis of life and behavior of dogs outside the landfill. During the recording, minor behavioral signs of anxiety behavior were analyzed using a developed checklist. The analysis of the obtained data was carried out both manually (blank questionnaires, small behavioral signs) and in semi-automated mode (accelerometry, video recordings and thermography). During the testing process, the advantages and limitations of each of the methods used in the context of the approach were identified, and the effectiveness of its use – in whole or in separate samples – for evaluating the behavior of companion dogs, working and service dogs was shown. The results are applicable for monitoring the behavior of companion dogs, working and service dogs, analyzing possible correlates of anxious and aggressive behavior, in zoopsychologic and ethological studies.