State collections of pathogenic microorganisms play an important role in ensuring the biological safety of Russian Federation. They carry out storage and comprehensive study of collection strains of microorganisms using modern methods. The collection fund is formed due to the deposition and receipt of strains upon request from other collections, also those isolated during the indication, diagnostic and monitoring studies of natural ecosystems, and in the course of experimental activities. The purpose of this work was to study the biological properties of the anthrax pathogen isolate obtained in the established manner, issue a passport for it and include it in the list of collection strains for further storage. An isolate of anthrax pathogen isolated during diagnostic studies from pigs in the city of Sengiley, Ulyanovsk region. The results of the study showed that the biological properties of the isolate are identical to the virulent strain “Ch-7” of the anthrax pathogen. As a result, the isolate was assigned to the genus Bacillus, species anthracis and designated as the strain “Sengiley”, with the introduction of these data necessary journals. The work carried out to study the biological properties of anthrax isolate showed a strict compliance with biological safety requirements with the execution of all necessary documents in accordance with regulatory documents.

The aim of the research was to develop a direct dot-immunoassay on a nitrocellulose membrane (NCM) using a conjugate based on colloidal gold for the qualitative determination of the presence of rabies virus antigen in pathological material. As the test samples, we used brain samples of various animal species, which were positive during the initial study by methods of fluorescent antibodies: foxes and mice. IFA and indirect ELISA carried out using diagnostic kits manufactured at the Federal Center for Toxicological, Radiation and Biological Safety. The materials present the results of primary laboratory tests of the test system for the indication of rabies antigen based on direct dotimmunoassay (DIA) 81 samples of pathological material, the brain of various animal species. It was shown that DIA has 100% specificity, and its optical signals correlate with the results of indirect ELISA. The proposed DIA method, in addition to independent application, can also serve as a basis for the design of test systems based on immunochemical analysis.

The immunocomplex vaccine against infectious bursal disease from the VNIVIP strain has strong immunogenic properties, including active expression of the IL-6 cytokine synthesis genes in the tissues of the bursa of Fabricius and cecum. This phenomenon stimulates a local non-specific immune response, resulting in a reduction in the representation of pathogenic and opportunistic microorganisms in the intestines of chickens. As a result of the studies, it was found that the relative expression in the tissues of the caecum of the intestines of chickens of the Loman White cross reached a 2.7-fold excess over the control level, and the relative expression in the tissues of the Fabricius bag - 15.6-fold excess over the control level. The relative content of bacteria of the Escherichia coli group, as sanitary indicative microorganisms, decreased by 4 times under the influence of the vaccine (from 0.253% in the control group to 0.064% in the vaccinated group). The variety of staphylococci under the influence of the vaccine was also reduced, and only unidentifiable representatives of the genus Staphylococcus were found in the vaccinated group.

The article analyzes the occurrence and spread of animal rabies disease in the Smolensk region for 2017-2021. At the same time, the following were studied: the incidence rate among susceptible species of farm animals, domestic carnivores and wild fauna, the geographical location of disadvantaged territories in which natural foci of rabies were activated during the specified period and the results of work on preventive measures and the elimination of animal diseases with rabies.
Starting from the 80s of the last century, the natural type of rabies epizootics began to spread on the territory of the region, this also indicates the presence of a reservoir of the causative agent of infection, the formation and persistent preservation of natural foci of rabies, supported not only by foxes, but also raccoon dogs, wolves.
As the analysis of the epizootic situation of animal rabies disease shows, the main source and distributor of rabies in the region are representatives of the canine family, who have been supporting stable foci of sylvatic rabies for many years. Their share among infected wild animals for five years (2017-2021) accounts for 48.5% of cases of rabies, but at the same time, during the analyzed period, rabies of domestic animals increases and amounts to 50.2%, which is reflected in chart No. 1.
Animal rabies has spread and is firmly rooted in the Smolensk region, which has actually turned into a vast, unified natural focal area.

The BLV-infected cows’ offspring are at risk due to a decrease in their viability and productivity indicators. The purpose of the studies is a comparative analysis of hematological parameters and indicators of body weight gain in obtained from immunocompromised cows calves when correcting their clinical status using the composition we have developed (patent No 2646831) and a broadspectrum antibiotic. According to our data, calves from BLV-infected mothers were born with a body weight of 6-7% less than calves from intact cows. With the correction of dyspeptic manifestations in calves by the proposed method, the average daily gain in animals remained at the level with intact ones (630-660 g / day), and when using an antibiotic, it was 300-500 g per day. Hematological studies have shown that with clinical manifestations of dyspepsia in neonatal calves, hypovolemia and pronounced leukocytosis are noted in the blood, the signs of which decrease by the 12th day of life during therapy. The glucose of blood serum in calves with dyspeptic syndrome was slightly reduced on the first day. There was a change in the blood electrolytes ratio, a decrease in total blood protein and albumin content, compared to intact animals. Thus, our studies have shown that when correcting dyspepsia in neonatal calves from immunocompromised cows using the composition we have developed, the body weight gain retained, which was due to the rapid normalization of the homeostasis in animals.

The authors analyzed the available literature data and statistics, and results can be found for leishmaniasis in Armenia. Between June 2019 and December 2021, 375 different breeds were deployed. 135 animals were subjected to a comprehensive study with laboratory diagnostics of blood serum for the detection of Leishmania infantum antigen. In 68 dogs, antigens were detected using the VetExpert Leishmania Ab immunochromatographic instrumentless test system. In the publication of the authors Yerevan and other cities of the republic. In the studies in animals affected by leishmaniasis, the cutaneous form of leishmaniasis (CL) prevailed, which was recorded in 85.3% of cases, and the visceral form of leishmaniasis (VL) was recorded in 14.7% of cases. Sexual and breed predisposition of the studied dogs to the disease with leishmaniasis was not found by the authors. The visceral form of leishmaniasis (VL) in the studies was recorded in dogs over the age of 4 years. The authors believe that in the near future it is necessary to conduct epidemiological, epizootological and entomological studies to continuously monitor the situation of leishmaniasis in the Republic of Armenia.

The combined use of hepatoprotectors and phytosorbents in theory is a promising method of pharmacotherapy of comorbid pathologies, as it creates the possibility of presenting them as the result of an extended search for the most relevant forms of manifestation of metabolic disorders, the results of which made it possible to identify general patterns of development and, accordingly, the main directions for their leveling.
It was revealed that the main pathogenetic trend is the failure of metabolic processes in the gastrointestinal tract, which reduces the efficiency of feeding and causes a decrease or fluctuations in productivity (or product quality), the subsequent accumulation of products of disturbed metabolic processes with toxic properties - the development of a local syndrome of endogenous intoxication, a violation of the processes of cavitary and symbiotic digestion in the gastrointestinal tract, with increased alimentary insufficiency, functional overload of the digestive organs and primarily the liver, imbalance of the microbiota and local barrier mechanisms, generalization of the pathological process in the form of the development of systemic endogenous intoxication with the corresponding toxic depression of immunity, functions of organs and body systems, including including dysfunctions and the development of pathology of the hepatobiliary system, in the form of systemic metabolic disorders with the occurrence of a secondary deficiency of nutrients and biologically active substances, acid disorders butalkaline balance and dystrophic phenomena.
The main purpose of this article is, based on the analysis of literary sources, to identify the pathogenetic basis for the combined use of drugs from the hepatoprotector groups and phytosorbents.
We searched for original studies in the scientific databases PubMed, Elsevier Science (Scopus) and Clarivate Analytics (Web of Science) over the past 20 years to identify the features of the above processes, after which a formalized content analysis of the found publications was carried out.
A better understanding of the various mechanisms involved in pathogenesis involving the liver and intestinal microbiota will contribute to the development of improved pharmacological approaches to the treatment of these pathologies.

In the manufacture of ophthalmic medicinal films, special attention should be paid to the choice of a film-forming substance, since both the shape of the future film and its medicinal properties as a whole depend on it. This article provides a laboratory analysis with a comparative assessment of the optimal concentrations of two film-forming substances, polyvinyl alcohol and gelatin. Most of the presented film formers have a number of disadvantages, such as thickness, insufficient strength and elasticity, heterogeneity, formation of cracks and creases. One of the requirements for ophthalmic medicinal films is the smoothness of the surface and the absence of sharp corners. Based on the foregoing, we set the goal of the study - to conduct a laboratory test of film-forming substances for the manufacture of ophthalmic medicinal films. An analysis of domestic and foreign works gave reason to use polyvinyl alcohol and gelatin as the basis for ophthalmic medicinal films. As a result of the study, we have established the optimal concentrations of film-forming substances (polyvinyl alcohol and gelatin) that meet the existing requirements. The optimal concentration of the gelatin solution was the ratio of 1:7. The addition of the plasticizer glycerol to gelatin
in the manufacture of ophthalmic medicinal films is mandatory. The optimal concentration of the solution of polyvinyl alcohol was the ratio of 1:15. Films from both film formers did not lose their shape, did not form cracks or breaks when introduced into the conjunctival sac. No irritant effect was observed. Laying the films did not cause difficulties. Forms of gelatin completely dissolved in the eye in 40 minutes, of polyvinyl alcohol - in 90 minutes.

Biocompatible nanoparticles attract the attention of researchers as a means of correcting a wide range of diseases. The carbonbased nanostructure, fullerene C60, is one of the most promising compounds. However, the use of compounds based on fullerene nanoparticles remains limited. Therefore, the development of domestic innovative medicinal compounds based on fullerenecontaining nanoparticles is one of the priority areas of veterinary medicine. The research was carried out in the laboratory of the Department of "Morphology, Pathology of Animals and Biology" of the Saratov State Agrarian University named after N.I. Vavilov. The first group served as a control. An aqueous solution of fullerene C60 was administered at a dose of 1 ml per (DV 5 mg / kg) 1 kg of body weight (group 2 animals). A compound based on an aqueous solution of fullerene C60 was also introduced, including an aqueous solution of fullerene C60, Lcarnosine and succinic acid in the following ratio of components, wt. / mg: an aqueous solution of fullerene C60 stabilized with pluronic F-127– - 5 ml (5 mg by DV), Lcarnosine -50 mg, succinic acid - 50 mg per 1 kg of body weight (group 3). The studied compounds were administered intramuscularly, once. Glycerin loading was carried out 24 hours after the introduction of the studied compounds. It was found that aqueous solutions of fullerene C60 have a distinct effect on carbohydrate metabolism in the body of white rats. The initial blood glucose level in animals of all groups turned out to be approximately at the same level, but the highest rate of gluconeogenesis was found in animals of group 2. As for the gluconeogenic function of the liver, in animals after the introduction of aqueous solutions of fullerene C60, the increase in newly formed glucose and the rate of gluconeogenesis significantly exceeded the control values. The results obtained indicate a failure in glucose metabolism after the introduction of aqueous solutions of fullerenes.

The goal of the present research was to investigate therapeutic and prophylactic effectiveness of levofloxacin following experimental challenge of chickens with varying doses of Escherichia сoli namely 1 minimum lethal dose (DLM) and 4 minimum lethal doses (DLM). We conducted two experiments on two-day-old Hisex Brown chickens. For the first experiment we used 6 groups of chicks (n = 25, in each group). The drug was administered via drinking water (with free access) 24 hours before the challenge. Chicks of Groups 1 to 4 received levofloxacin via drinking water at concentrations 50 mg/L, 100 mg/L, 200 mg/L and 300 mg/L for 5 days. Group 5 was control, Group 6 was intact. The chicks were challenged with 1.5 х 108 E. сoli bacterial cells per 0.5 mL (1 minimum lethal dose (DLM)) intraperitoneally. The second experiment was conducted similarly but the infecting dose was increased by 4 times (4 minimum lethal doses (DLM)).
Administration of levofloxacin at concentration 300 mg/L both in the first experiment, when the infecting dose was 1 minimum lethal dose, and in the second experiment, when the infecting dose was 4 minimum lethal doses, proved that the drug has the same high therapeutic and prophylactic effectiveness of 96 %. Administration of the drug at concentration 200 mg/L showed 100 % effectiveness in the first experiment. But in the second experiment levofloxacin at the same concentration ensured survival of only 88 % of the challenged chicks. When the drug was administered at concentration 100 mg/L we observed reliable change in indices. Accordingly in the first experiment 88 % of the chicks survived. In the second experiment, when the infecting dose increased to 4 minimum lethal doses, only 52 % of the chicks survived. Administration of levofloxacin at concentration 50 mg/L did not show significant therapeutic effect.

Currently, one of the main indicators characterizing the safety of feed for productive animals is the content of toxic elements in them. According to the requirements of MDU No. 123-4 / 281-8-87 "Temporary maximum allowable level (MRL) of the content of certain chemical elements and gossypol in feed for farm animals and feed additives", mercury, cadmium, lead are of the highest veterinary, sanitary and toxicological significance, arsenic, selenium. The danger of these substances lies in the ability to accumulate in the body of an animal and cause various pathologies, affecting the urinary, hematopoietic, digestive and nervous systems, generally retard the growth and development of farm animals, reduce resistance, productivity and increase the risk of detecting toxicants in agricultural products of animal origin.
The purpose of the study was to assess the safety of plant foods for the content of mercury, arsenic, selenium, lead and cadmium using atomic absorption spectroscopy.
The study materials were 76 samples of various plant foods for productive animals: grass meal, linseed cake, oats, vegetable feed. The amount of toxic elements was determined according to GOST R 55447-2013 and GOST 31651-2012 using an MGA-1000 atomic absorption spectrometer with Zeeman correction of non-selective absorption (LUMEX Group of Companies).
As a result of the studies, it was found that in all samples of plant-derived feed for productive animals, the amount of toxic elements did not exceed the maximum allowable level. Thus, the amount of mercury in the studied samples averaged 0.55±0.04 mg/kg, cadmium - 0.86±0.04 mg/kg, lead -0.29±0.01 mg/kg, arsenic - 0 .24±0.01 mg/kg, selenium – 0.44±0.02 mg/kg. The established concentrations of toxic elements did not exceed 1.0 mg/kg and were less than 1.5% of the maximum allowable level, which meets the requirements for the toxicological safety of feed for productive animals.

The spread of oncological diseases is currently one of the main problems in both humanitarian and veterinary medicine. Despite the high achievements of domestic and foreign scientists of modern veterinary medicine in the field of diagnosis, treatment and prevention of oncological processes, the number of cancer-affected animals is quite large and continues to grow steadily. Therefore, improving the complex of diagnostic studies for neoplasms among dogs and cats is one of the priority areas of veterinary medicine. The research was conducted on the basis of the veterinary clinic of the Center for Animal Beauty and Health "Zoostyle" IP Gorinsky V.I. (Volgograd) and the Department of "Morphology, Pathology of Animals and Biology" of the Saratov State Agrarian University. In the period from 2018 to 2021, 244 patients, including 127 dogs and 117 cats, were examined by an oncologist at the veterinary clinic of the Zoostyle Center for Animal Beauty and Health.
All the animals belonged to residents of the city of Volgograd. When an animal was admitted to the clinic for an oncological appointment, animals with any visual signs of a neoplasm in the projection of the breast were selected for research. As a result of the physical examination, based on the results of laboratory, X-ray and ultrasound examinations, MR tomography, it was found that breast tumors (OMJ) are more common among dogs and cats. In the population of dogs, OMH accounted for 33.8% (n=43) and 62.4% (n=73) of all cases of oncological pathology in cats. Depending on the gender, breast neoplasia was observed in females - 100%, in cats, females accounted for 89%, and males - 11%. The results obtained indicate that the introduction of a complex of modern high-tech diagnostic methods into veterinary oncology practice is a key element that significantly affects the prospects for providing specialized care and prognosis.

The study was aimed at studying the relationship between the concentration of vitamin A in the turkey diet and the change in the amount of ciliated epithelium in the bronchi. Methods and methodology: to increase the dosage of vitamin A, the “Alphabet AD3E” multivitamin complex was used in the experimental group for 10 days with the slaughter of poultry on days 3, 5 and 10 of the study with the study of macro and microcartins of the epithelium with the counting of ciliated epithelium cells per 1000 cells in each bird. Subsequently, the concentration of cells of the ciliated epithelium was analyzed in the experimental and control groups. The results of the study demonstrated not only an increase in the number of cells of the ciliated epithelium in the experimental group compared to the control group by 27.3% at the end of the experiment, but also allowed us to note a greater speed of processes during the recovery period after the respiratory disease of the turkey. The scientific novelty lies in the study of the relationship between the concentration of vitamins in the diet of poultry and the quantitative change in the epithelium of the respiratory system of poultry, which in turn is necessary for a broader understanding of the causes and spread of diseases of the respiratory tract.

In recent years, the anatomy of a goat is relevant and attracts the attention of veterinary morphologists and clinicians. The goat is used for a number of purposes, including such as: meat and milk production, biomedical research. The peculiarity of the topography of the pharynx as an organ is that it is located between two vital systems (digestive and respiratory). Food and air pass through the pharynx on the way to the esophagus or larynx, as well as during belching in ruminants, which plays an important role in preventing suffocation. There are also tonsils and single lymph nodes in the pharynx, which perform a protective function. In connection with the above about the relevance of pharyngeal research, we set a goal to study the morphology of the goat's pharynx, and use the Anglo-Nubian breed as a model. The study of the morphology of the throat of the Anglo-Nubian goat breed was conducted on the basis of the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine. The dated material was delivered from the farm of the Moscow region of the Russian Federation "Gzhelskoe podvorye". The age of the studied animals was 1 year and older. The age was determined from the words of the chief veterinarian of the farm "Gzhel farmstead", as well as according to the bonus cards and according to the dental formula of the methodology of Professor I.I. Kalugin, a total of 15 individuals were studied. During the study, such methods as: fine anatomical dissection, morphometry, photographing were used. According to the results of the study, the species and breed anatomical and topographic characteristics of the structure of the pharynx, as well as the structural and functional muscle groups of this organ were established. Morphometric parameters of the pharynx of the Anglo-Nubian goat breed were determined. These studies can be used by veterinary specialists in goat farms for the prevention and treatment of diseases of the digestive and respiratory systems.

Intranasal neoplasms in cats are less common than in dogs and, according to the literature, account for up to 1% of all neoplasms in cats. Most often, carcinoma and sarcoma develop in cats of the middle age group, and intranasal lymphomas are more common in younger animals.
The etiological factors causing intranasal neoplasms in cats are diverse. The algorithm for diagnosing nasal neoplasms in cats depends on the clinical manifestations of the process and includes diagnostics aimed at determining the clinical stage of cancer and making a final diagnosis based on a morphological conclusion. And also a diagnostic algorithm is necessary for the choice of treatment methods. The determination of the clinical stage directly depends on the visualization of the neoplasm in the nasal passages, the involvement of one or two nasal passages in the oncological process, the degree of spread of the tumor into the surrounding tissues – using visual diagnostic methods such as MRI and CT aimed at determining the localization of pathology, the spread, the degree of invasion and the degree of involvement of blood vessels in a specific oncological process. Diagnostic methods such as palpation of regional lymph nodes, chest X-rays and ultrasonography of abdominal organs are aimed at determining the clinical stage of oncopathologies.

The state of the immune system of newborn animals largely determines their further development, morbidity, and productive qualities. Various diseases of pregnant animals to a certain extent affect the body of the fetus, this is especially true if the disease is characterized by an erased clinical picture and it is difficult to diagnose it in a timely manner. One of these diseases is genital mycoplasmosis of cattle, which is widespread both in our country and abroad. Despite this, many aspects of the pathogenesis of genital mycoplasmosis remain poorly understood, especially the state of the immune system. A study was made of the content of immunoglobulin classes in healthy dry cows and cows with genital mycoplasmosis, as well as in calves born by them. The results showed a significant decrease in the level of immunoglobulins and a redistribution of their classes in cows with genital mycoplasmosis. Changes of a similar nature, but more pronounced, were also noted in calves born from these cows. Studies show that pregnant cows with genital mycoplasmosis develop an immunodeficiency state, characterized by a decrease in the total amount of immunoglobulins, a significant decrease in the level of Ig G and an increase in the concentration of Ig A. A similar immunodeficiency state was observed in calves obtained from these cows. The noted changes will be useful for the development of rational therapy for genital mycoplasmosis in cows.

In the Yamalo-Nenets Autonomous District were studied 169 heads of Nenets deer from birth to 18 months of age The maximum rate of weight gain of live weight of calves is observed in the first 6 months of postnatal development and has sexual differentiation: in males it was 52.5, in females – 46.5 kg. From 6 to 12 months of age, which falls during the wintering period, in the studied groups of deer there was a drop in absolute indicators of live weight gain to minus values: males -5.3 kg, females -1.7 kg. In the period from 12 to 18 months of age, the absolute growth rates of males and females turned out to be equal. The rate of linear growth and the formation of the physique of young deer in the period from birth to 6 months of age, no significant difference between males and females was found either visually or instrumentally.. During the first wintering period, an increase in absolute value was observed by measurements associated with the growth of the skeleton: height at the withers, height at the elbow, head length, chest depth, oblique length of the butt. The age period from 12 to 18 months is characterized by a significant increase in linear body sizes in the studied deer, but the difference in almost all measurements did not exceed 4%. A comparison of 10 indices of physique in animals showed that at 6 and 18 months of age, the main proportions of the physique are close, which indicates a high rate of formation of the physique in young domestic reindeer. A comparison of the physique indices revealed no signs of sexual dimorphism for any of them, except for the pelvic index, which was higher in females at all age periods and the broadbodied index at 18 months of age.

The Yorkshire pig breed was bred in the 19th century by the English farmer Joseph Tooley and presented at the agricultural exhibition in Windose in 1851. Pig breeders immediately appreciated this breed on merit for its calm disposition and unpretentious lifestyle, feeding and maintenance. Farmer Joseph Tuley decided to assign the name of the breed immediately, and in particular to link it with his county - Yorkshire. The Yorkshire pig was the result of crossing representatives of the white Leicester and Chinese and English long-eared. Farmer Joseph Tuley decided to breed a new bacon breed, which became the goal of his life and brought him fame and an impressive income. Yorkshire piglets were brought to Russia only in the post-war years and immediately became quite popular. Currently, this breed of pig ranks fourth in the world in terms of prevalence and popularity. There are about 1.5 million individuals of this breed of pigs in the Russian Federation. Currently, diseases of pigs associated with the urinary tract are very widespread. The causes of this pathology can be infectious microorganisms, injuries of various etiologies, metabolic disorders and vascular apparatus of the organs of the urinary system. This can lead to the occurrence of diseases such as nephritis, nephrosis, pyelonephritis, urethritis, cystitis. Without knowledge of anatomical and topographic features of the structure of the organs of the urinary system, it is problematic to diagnose diseases and pathologies, as well as to carry out timely treatment. The purpose of our study was to study the anatomical patterns of kidney structure in Yorkshire pigs in the age aspect. The material for the study was three age groups of pigs - newborns 1-7 days (early neonatal period); piglets 10-14 days (neonatal period); piglets 20-28 days (late neonatal period) weighing from 2000 to 3500 g. To achieve this task, a complex of traditional anatomical research methods was used: fine anatomical dissection, photographing and morphometry. During the study, it was found that the kidneys of Yorkshire pigs are located in the retroperitoneal space. Topographically, the right and left kidneys are located at the same level under 1-4 lumbar vertebrae. The kidneys of male Yorkshire piglets are much larger and larger in absolute and relative terms than those of females. The study also found that the maximum kidney growth in Yorkshire pigs in the observed period ranged from 10-14 to 20-28 days of age.

The reproductive capacity of livestock can be increased by breeding. The influence of controlled changing factors on the reproductive ability of the Cows of the first calving the Sychevskaya breed was studied, taking into account the inbreeding coefficient in order to improve the breeding process. In breeding work with animals, two methods of crossing are used: outbreeding and inbreeding. A measure of the genetic consequences of inbreeding is the inbreeding coefficient. The studied number of first-calf cows was grouped into groups according to the inbreeding coefficient. Calculated by the intergroups and intragroups differences, the strength of influence and reliability in the cows of first calving the method of variance analysis. The average age of the first calving in inbred cows was 30 months, overestimated in animals with a coefficient of 12.5 and higher. The effectiveness of the multiplicity of inseminations in groups by the first lactation is excellent (1.4-1.5) and good with close inbreeding (1.7). In first-born heifers with an inbreeding coefficient of 0.1-0.59%, the average duration of the period between the calvings is 10 and 9 days less than in animals with moderate, close and closely related breeding. The fertility index of the first heifers of the groups is average, except for animals with close inbreeding. The results of the analysis of variance in breeding work with factors are statistically significant, but have unequal alternative variability. For further breeding work, taking into account the reproductive ability of animals, it is necessary to conduct inbred selection in moderate degrees. It is also necessary to take into account the reliable influence of controlled factors: such as the age of the first calving, the multiplicity of insemination, the fertility index, which allow increasing the efficiency of selection work.

The aim of the work is to study agerelated and pathological changes in the tissues of different parts of the heart of rats aged 18-23 months. Neuroimmunohistochemical reactions for PGP 9.5 protein, tyrosine hydroxylase, synaptophysin, von Willebrand factor and staining with toluidine blue for mast cells were used. A correlation was found between the level of decrease in the intensity of the innervation of the heart and pathological changes in the tissues of the heart. Destructive changes in the nervous apparatus, the presence of lymphomononuclear infiltrates and mast cells were revealed in the aortic-pulmonary region, atria and ventricles. Along with the degeneration of the nervous apparatus, reactive and destructive changes in arteriole and capillary endothelial cells, as well as their death, an increase in the number of reserve sinusoidal capillaries, an increase in the secretory activity of endotheliocytes, and pigment accumulation in the cavity of the subaortic cone were revealed.

The article presents the results of a study of coagulation hemostasis in cows under conditions of intensive and extensive production in different physiological periods (dry, fresh and at the peak of lactation). Disorders of coagulation hemostasis have been revealed in productive animals in different physiological periods under both intensive and extensive housekeeping, and a relationship has been established with feeding, keeping and exploitation.
It has been established that the index of activated partial thromboplastin time (APTT) is significantly higher in dry cows with both intensive and extensive management. Prolongation of prothrombin and thrombin time and a decrease in the amount of fibrinogen were noted, which indicates a deficiency of coagulation factors and indicates hypo- or dysfibrinogenemia. For the first time, a conclusion was made about the possibility of using indicators of coagulation hemostasis as an objective assessment of the influence of technological factors in conditions of intensification of production.

The article presents the data of DNA testing of Holstein cattle by the APAF1 gene. The structure of the Tatarstan population was studied in comparison with world experience. The aim of the study was to study the allelic polymorphism of the apoptosis peptide activating factor 1 gene (APAF1; g.C6315040T; p.Gln579Q→X), the cause of the fertility haplotype (HH1), in the domestic population of Holstein cattle of the Republic of Tatarstan. Genotyping was carried out by PCR-RFLP followed by electrophoretic separation in agarose gel in the presence of ethidium bromide. For the first time in the Republic of Tatarstan in the conditions of the Dairy farm "named Lenin” carried out the identification of cattle by the locus of APAF1 - BstC8 I, assessed the genetic equilibrium and structure of the population. As a result of gene diagnostics, two alleles and three genotypes were identified. The frequency of occurrence of alleles Q and X was 0.988 and 0.012; genotypes QQ and QX – 97.5 and 2.5%, respectively. Since homozygous XX embryos do not survive, they are never found among born animals. Chi-quad testing showed that the studied population is in genetic equilibrium according to the Hardy-Weinberg law. Our studies confirm an insignificant share of the presence of animals-carriers of the lethal allele in the population of Holstein cattle of domestic selection of the Republic of Tatarstan. In order to contain the spread of the mutant allele X of the apoptosis peptide activating factor 1 gene, it is recommended to conduct DNA testing of polymorphism of the APAF1 gene during the selection of pairs for breeding.

High-performance liquid chromatography mass spectrometry is a hybrid method and combines independent processes of liquid chromatographic separation and mass spectrometric analysis, which makes it possible to effectively determine the concentration of various substances in complex substances. The optimal parameters for the determination of progesterone, 17-hydroxyprogesterone capronate (17-OHPC) and aglepriston in the blood plasma of cattle by this method have been established in the work. The quantitative determination of the components was carried out by the method of an external standard using reference substances and preliminary construction of calibration dependencies (absolute calibration). To account for the effect on the result of the analysis of various components of blood plasma, the matrix calibration method was used using "pure" plasma, i.e., it did not contain detectable compounds. It was experimentally determined that the time of progesterone peak release is within 2.72 minutes, and the optimal precursor ion is m/z =315.3. In the course of the work carried out, it was found that in the blood plasma of animals, endogenous progesterone is well detected by the developed method according to the parameters set for the synthetic analogue. The peak time of 17-OHPC occurred after 4.20 minutes, and the optimal precursor ion had a mass of 429.2 au. The first stage of studying the kinetics of 17-HPC in cattle showed that the steroid is well visualized on the chromatogram even in low concentrations. The outputs of the peaks of aglepriston were observed at 2.25 minutes, and the optimal precursor ion was equal to 432.2 au.m. The chromatogram even at low concentrations of the steroid had a low noise level, and the concentration of the steroid in the blood plasma a day after injection of 20 ml of 3% aglepriston solution to a lactating cow was 7.2 ng/ml. Thus, optimal parameters were selected for determining the concentration of selective progesterone receptor modulators in the blood plasma of cattle, which allows for further evaluation of the pharmacokinetic properties of these steroids after their use.

Malnutrition syndrome is widespread in allergic enteropathy in dogs, causing a violation of absorption and transport of nutrient substrates in the intestinal mucosa, which serves as a trigger for subsequent metabolic changes in the gastrointestinal system, affecting hepatocytes through the activation of lipid peroxidation processes and the development of shifts in the redex system. homeostasis. As a result of biochemical and morphological studies of the blood of sick animals with allergic enteropathy with severe gastrointestinal syndrome, a violation of metabolic processes was established (T-Pro - 59.46±0.32 g/l and 63.34±0.53 g/l; ALB - 19.71±0.64 g/l and 18.56±0.50 g/l; GLB - 39.75±0.82 g/l and 44.78±0.96 g/l; A/G - 0.49±0.06 and 0.41±0.08; RBC - 5.85±0.17×1012/l and 5.67±0.16×1012/l; Na - 134.50±6.10 mmol/l and 130.80±5.97 mmol/l, K - 3.43±0.10 mmol/l and 3.40±0.09 mmol/l, Ca - 2.15±0.07 mmol/l and 2.13±0.06 mmol/l), redox homeostasis (ALT - 108.95±11.00 U/l and 115.73±9.39 U/l; AST - 62.90±6.05 U/l and 60.30±5.80 U/l; ALP - 196.05±19.20 U/l and 210.20±23.91U/l) due to activation of lipid peroxidation processes (MDA - 23.10±1.06 µmol/ml and 24.25±1.40 µmol/ml; DK - 1.08±0.15 uA/ml and 1.15±0.09 uA/ml) and antioxidant potential depletion (CT - 0.54±0.02 Bach units and 0.55±0.03 Bach units; SOD - 18.23±1.59 EU/mg protein per minute and 19.98±1.91 EU/mg protein per minute; GSH-Px - 26.69±2.46 µmol/ml and 28.31±3.02 µmol/ml; Vitamin A - 0.66±0.05 mcg/ml and 0.59±0.03 mcg/m; Vitamin E - 8.49±0.90 mcg/ml and 7.87±0.98 mcg/ml). The presence of direct correlations between the level of trophological disorders due to the development of intestinal malabsorption syndrome and the degree of redox homeostasis disorders was revealed.

The aim of the study was to establish the features of the histological organization of pancreatic tissues on the example of a domestic bull. For its implementation, pancreatic tissue samples of five sexually mature one-year-old cows of a black-and-white breed obtained by biopsy were used. The selected material was fixed in a 10.0% solution of neutral formalin for a day, after which it was poured into paraffin according to the generally accepted method. Histological sections were made from the obtained blocks, which were stained with hematoxylin and eosin, according to Van Gieson and trichrome according to Mosson. It has been established that the studied organ in the studied animals belongs to complex alveolartubular glands. From the outside, it is covered with a delicate connective tissue capsule, giving rise to connective tissue strands (trabeculae) passing between its lobules. Vascular elements, nerve trunks and excretory ducts are identified as part of these structures. The gland itself, in accordance with its function, includes two parts – endocrine and exocrine. The terminal sections of its exocrine part are represented by pancreatic acinuses. As part of the latter, two departments can be distinguished - secretory (formed by serous endocrinocytes) and ductal (formed by epithelial cells (centroacinous) of the initial sections of the insertion excretory ducts). The secretory department of the acinus includes from seven to eleven cells having a pyramidal shape. They contain one welldeveloped basophilic rounded nucleus, and two zones are revealed in their cytoplasm. The basal – homogeneous – zone has a basophilic color and is located in the basal part of the cell. The apical – zymogenic (apical) zone contains secret granules and is colored oxyphilically. The endocrine part of the gland is represented by pancreatic islets (islets of Langerhans) formed by strands of closely interconnected endocrine cells (isulocytes) surrounded by abundant capillary loops forming branched networks inside the islet. Insulocytes are small cells having a polygonal shape with a poorly defined border. In their composition, one rounded or oval nucleus is revealed, containing evenly distributed small-smiley chromatin.

Mastitis is the most important disease in the dairy industry. Antibiotics are considered to be the first choice in the treatment of the disease. However, the problem of antibiotic residue and antimicrobial resistance, leads to many restrictions on antibiotic therapy in the dairy sector worldwide.
The work is devoted to the study and analysis of the sensitivity of pathogens of acute mastitis in cows to different antibacterial drugs. Bacteriological studies were carried out according to the generally accepted methods. Antibiotic sensitivity was determined by the disk diffusion method.
The dynamics of isolation of the main pathogens of acute mastitis in cows and their antibiotic sensitivity within a 5-year period (2017-2021) in the central region of Russia was analyzed. It has been established that in recent years gram-positive infections became predominant, while coagulase-negative staphylococci are increasingly replacing S. aureus. Representatives of the genus Enterococcus were predominant causative agents of the disease. High-level multidrug resistance of all isolated strains of pathogens was determined (97%).
The improvement of laboratory diagnosis and strict control over the use of antimicrobials need to reduce the level of resistance and the spread of multi-resistant pathogens of pyo-inflammatory diseases.

The disease of cows with mastitis is a serious problem in the intensive use of animals and the financial well-being of dairy farms [1,5]. The development of animal health programs, as well as the introduction of an integrated approach to the prevention of mastitis using modern pharmacotherapy, is the main task of veterinary medicine today [10,11]. Different groups of microorganisms cause mastitis; recently, frequent cases of participation of Klebsiella, gram-negative polymorphic microorganisms, can be noted [7,8]. Analysis of statistics shows that mastitis becomes recurrent in 40% of cases. The repeated occurrence of mastitis occurs as a result of the weakening of the body and the immune system, as well as the development of bacterio-resistance [9]. In our scientific work (2015-2021), various methods of preventive and therapeutic measures were used on farms. The main ones were: preparation of the udder for milking, treatment of milking and dairy equipment with disinfectants, compliance with machine milking regimes. Every year, the latest drugs were used to treat mastitis and increase the overall resistance of the body and the immune system [2,3]. The purpose of this article is to create a unified approach in the prevention and treatment of mastitis, thereby pursuing the preservation of the health of dairy cows, obtaining environmentally friendly products and reducing the economic damage to farms. In the complex use of modern medicines to increase the overall resistance and immune system of the body, as well as the processing of milking and dairy equipment, the incidence of mastitis in cows was reduced by 2 times. The use of new anti-mastitis drugs showed high efficiency, which reached 86.7-96.7% of each, and when two drugs were used simultaneously, it was 98.2% [4].

The article presents data on the effect of castration on changes in indicators reflecting pigment, enzyme and lipid metabolism. The experiments were carried out on 14 boars (aged 5 month), divided into two groups ‒ control and experimental (n=7 in each).
Medical support before castration (using an open method) consisted of an intramuscular injection of ketoject, and during the post surgery period ‒ in the repeated use of the abovementioned drug, as well as cobactan and hipratopic spray. The boars of the experimental group were additionally injected with thymogen, which is a synthetic analogue of one of the thymus hormones.
Blood sampling was performed before the surgery, as well as on the 14th and 30th day after it; serum was obtained by the conventional method. The content of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total and direct bilirubins, cholesterol, triglyceride, lactate dehydrogenase, α -amylase, γ-glutamyltransferase were determined and the de Ritis coefficient was calculated.
It was found that castration in both the control and experimental groups (against the background of immunocorrection) caused significant changes in the biochemical status of animals in both groups, in most cases having the same pattern. Thus, on the 14th day, 9 out of 10 indicators were characterized by negative dynamics, and on the 30th ‒ by positive, in five cases of which they exceeded the level of the pre-surgery period. Only in relation to triglycerides, an upward trend
was noted at all stages of the studies. The de Ritis coefficient was diverse.
The most pronounced changes were recorded at the catabolic phase in the enzymatic system of indicators ‒ aminotransferases (especially ALT, γ-glutamyltransferase, lactate dehydrogenase, α-amylase). The anabolic phase is characterized by the normalization of indicators of AST, alkaline phosphatase, γ-glutamyl transferase, lactate dehydrogenase; below the initial, but exceeding the standard values ‒ AlAT; upper limit of reference intervals ‒ total bilirubin, cholesterol, triglycerides.
The use of thymogen significantly reduced the negative impact of surgery, especially at the catabolic phase, and contributed to a more rapid normalization of indicators reflecting enzyme metabolism. Their dynamics in the experimental group was characterized by a smaller amplitude and intervals in the min – max range compared to the control group. At the catabolic phase (in most cases), there were no significant differences in the dynamics of lipid and pigment metabolism between the groups (against the background of reference values); at anabolic phase – an increase in the level of total bilirubin, cholesterol and triglycerides.

Digital dermatitis, Mortellaro's disease, is one of the most common diseases of the hooves of cattle on farms, which can lead to significant economic losses. Digital dermatitis is considered a polybacterial disease in which the microbiome composition changes as the different stages of the disease progress. According to the literature, bacteria such as treponemas, mycoplasmas, porphyromonas and/or fusobacteria may play a key role in the pathogenesis of digital dermatitis. Cattle digital dermatitis has a staging ranging from minor ulcerations to hyper- and dyskeratic proliferation of the papillary layer of the skin base. The foci are localized on the palmar or plantar surface of the fingers and hooves, between the fingers, along the perimeter of the corolla, under the rudimentary fingers and above the horn capsule. The article evaluates the frequency of its occurrence, the impact on the productivity of dairy cows and compares the effectiveness of the treatment of Mortellaro's disease with the use of beech tar and Terramycin spray. In the studied livestock, digital dermatitis was detected in 1.5% of animals. Most often, digital dermatitis of various stages was identified in cows of II, III, IV and more lactation. A decrease in the average daily milk yield in cows with Mortellaro disease was determined - 21.78 kg of milk, while the average value for the household is 24 kg. Also, the insemination of 14 cows out of 18 sick animals after the first insemination 42.9% were barren. In 90% of the animals, the pelvic limbs were affected, pathological foci were localized in the heel area in 74% of cases, in the interhoof arch in 23%, and in the corolla in 3%. In 78% of the animals one limb was affected. Surgical removal of the affected tissues, the use of a bandage with beech tar reduced the treatment time by 5-7 days compared with the use of Terramycin spray.

The presented study analyzes the healing effect of pure cell-free plasma and plateletrich plasma. The study was conducted on Wistar rats. Three groups of rats were formed for the experiment: a control group and two experimental ones (No. 1, No. 2). Burn wounds were inflicted on animals under sevoflurane anesthesia in the interscapular region with a copper-plated disc with a diameter of 20.0 mm heated in the flame of a gas burner to a temperature of 300.0 OC by applying it for 2.0 - 3.0 seconds. In the control group, treatment of burn wounds was not carried out, but surface application of aerosol 10% lidocaine was used to reduce the pain syndrome. For rats of experimental groups No. 1 and No. 2, treatment of burn wounds with plasma was started on the 5^th day after injury. Rats of experimental group No. 1 were treated by injecting cell-free plasma under and around the burn. Rats of experimental group No. 2 were treated by injecting platelet-rich plasma under and around the burn. Monitoring and evaluation of wound healing was carried out by measuring their area. Photo fixation and photo documentation were carried out at the time of the burn wound and then on the fifth day after the injury (the first injection of plasma samples), on the 14th day after the injury, on the 23rd day after the injury and on the 30^th day after the injury. The result of the study showed that both cell-free plasma and platelet-rich plasma accelerate the healing of a burn wound in comparison with the control. But platelet plasma, in comparison with cell free plasma, has a stronger therapeutic effect, significantly accelerating the contraction of the wound edges in the very first days after administration.