Immunological immaturity of calves and suboptimal housing conditions contribute to the development of diseases in young cattle, leading to significant economic losses due to mortality, reduced weight gain, and forced culling. With the growing antibiotic resistance, alternative treatment methods, including immunostimulants such as the synthetic oligopeptide Allokin-alpha, have become increasingly relevant. The immunostimulatory properties of Allokin-alpha include induction of endogenous killer cell synthesis, activation of the natural killer (NK) cell system, stimulation of cytotoxic lymphocyte-mediated detection of infected cells, and enhanced cytokine production. This results in a shift of immune response from humoral to cellular immunity. The study aimed to evaluate the effects of Allokin-alpha immunostimulant on clinical and hematological parameters in calves. The research was conducted during spring at a breeding farm in Leningrad region on threemonth-old Holstein calves and at the Department of Microbiology, Virology, and Immunology of SPbSUVM (St. Petersburg State University of Veterinary Medicine). Allokin -alpha was administered subcutaneously at a dose of 1 mg/head twice with a 6-day interval. To assess Allokin-alpha's effects on experimental animals and rule out concurrent diseases, clinical examinations and hematological blood tests were performed at the beginning and end of the experiment. Blood samples were collected before drug administration and after treatment completion for dynamic evaluation. Hematological testing was conducted at the SPbSUVM laboratory, analyzing leukocyte, erythrocyte, and platelet counts, hemoglobin levels, leukogram profiles and derived leukocyte indices in control and experimental groups. The application of Allokin-alpha normalized leukocyte counts in calves with bronchopneumonia mitigated inflammatory responses.

Glanders is an infectious disease of horses and other single-hoofed animals from the equine family; some other animals may also be affected. Glanders may manifest itself in nasal, pulmonary and cutaneous forms. The course of the disease may be acute or chronic. The aim of the study was to identify ideas about the occurrence and treatment of glanders in the 17th century, according to information from printed sources of that time in English and Spanish. The materials for the study were printed sources of the 17th century in English and Spanish, which contain information about the diagnosis, etiology, pathogenesis and methods of combating glanders in horses. During the study, we found that all the sources studied mentioned glanders, most often dedicated to it in separate chapters. Most authors refer to knowledge obtained from antiquity in chapters on glanders, and describe glanders as a “very bad disease”, “a disease that is unlikely to be cured” (malleus from the Greek malis - bad, evil). Glanders was mainly the nasal form of the disease, the pulmonary and cutaneous forms are described in some sources under the guise of other diseases with an indefinite chapter title. Obviously, glanders were often confused with myt and African glanders. The main cause of glanders was considered to be either "bad" water or contact with sick animals. "Humors" were considered to be the causes of glanders. Among the main methods of treatment described in printed sources of the 17th century, bloodletting, the use of local remedies, and "panacea" remedies were described.

Brucellosis is a dangerous zoonotic disease caused by bacteria of the genus Brucella. having a significant negative impact on the productivity of farm animals. In the Russian Federation, successes in the fight against this disease in cattle are associated with the use of a vaccine based on the Brucella abortus 82 strain, as well as the timely detection of infected animals. This work is devoted to the preparation and study of the serological activity of recombinant O-antigen for the indication of antibodies against brucellosis. As a result of conducting search queries in the GenBank database, we identified the amino acid sequence of the O-polysaccharide antigen brucella –WP_002967174.1. This sequence was optimized for protein translation in mammalian cell culture, synthesized, and cloned into the pVax1 plasmid. pVax1 was developed by transformation of Escherichia coli cells of the DH5a strain by heat shock, with selection for the kanamycin resistance gene with further isolation and purification of plasmid DNA. Transfection of HEK293 cells with the resulting genetic construct led to the expression of the target antigen, the presence of which in the liquid taken from the cell culture was established using vertical electrophoresis in 12% PAAG based on the visualization of major patterns at the level of 70 kDa. As a result of ion exchange and gel filtration chromatography, it was possible to obtain purified O-antigen in dissolved form at a concentration of 4.7 mg/ml. The resulting drug was used in a dilution of 10 micrograms/ml, as an antigen, during indirect solid-phase ELISA to indicate antibodies in bovine blood sera against S and R brucella antigen. The coefficient of specificity was calculated with respect to ELISA data with blood serum at a dilution of 1:256. Thus, in the reaction with bovine blood serum against Brucella abortus, the specificity coefficient was 6.29, against S and R brucella antigens – 6.1 and 6.77, respectively. The results of the study can make a significant contribution to the development of methods for the diagnosis and treatment of brucellosis, as well as to the creation of new vaccine preparations.

The widespread prevalence of leukemia among cattle poses a significant threat to the profitability of cattle breeding, which is associated with the regulations for the recovery of unfavorable enterprises, which pro-vide for the complete replacement of infected livestock with healthy animals. In this regard, it is necessary to find out what factors affect the level of animal infection and develop mechanisms to improve the health of territories from leukemia. The purpose of the study was to study the prevalence of leukemia in cattle in the Tyumen region depending on the natural and climatic zones, taking into account the organizational and legal form of enterprises engaged in cattle breeding in various municipal areas, including large farms, and the private sector, where cases of leukemia were identified. Monitoring of the epizootic situation on bovine leukosis in Tyumen Oblast was carried out based on the results of serological and molecular genetic stud-ies of cattle for detection of the leukosis virus and antibodies to it, comparing the data with the climatic and geographic location of enterprises and their form of ownership. It was found that in Tyumen Oblast the bovine leukosis virus was not detected only in three northern regions - Tobolsk, Uvatsky and Vagaysky. The most difficult situation on cattle leukosis is observed in the subzone of the northern forest steppe, where the epizootic process occurs with high intensity. It is noted that leukosis is recorded mainly at enter-prises containing no more than one thousand livestock, and at large mega-complexes no infection of cattle was recorded. The level of infection of cattle with the leukosis virus in agricultural enterprises was 3.63±2.95%. In private subsidiary farms, the level of seropositivity of cattle with the leukemia virus was 5.54±4.42%. The highest level of infection was detected in peasant and farm households – 25.59±12.11%. Considering the active participation of peasant and farm households in the spread of epizootics, strategies for improving animal health and maintaining the number of cattle should be adapted to the latest scientific discoveries and practical data.

Microorganisms capable of forming biofilms are significantly resistant to antibiotics and bacteriophages. Cattle diseases caused by biofilm-forming pathogens are a serious problem for livestock production, since the presence of biofilm complicates the use of available therapeutic drugs. In addition, due to differences in antibiotic concentrations in biofilms, microbial cells are often exposed to concentrations below inhibitory concentrations and can develop resistance. The global increase in resistance to antimicrobial and chemotherapeutic drugs is a serious problem in livestock production. The matrix of extracellular polymeric substances within biofilms can physically impede the penetration of antibiotics and bacteriophages, which also contributes to the survival and spread of multidrug-resistant bacteria among farm animals. Therefore, it is necessary to find effective methods to combat biofilm-forming microorganisms. Silver nanoparticles (Ag) are well known for their bactericidal action and ability to reduce the synthesis of bacterial biofilms. Therefore, colloidal silver consisting of silver nanoparticles is an attractive addition to existing therapeutic and preventive measures in animal husbandry. In the course of the study, we assessed the intensity of biofilm formation of causative agents of calf bronchopneumonia (Escherichia coli (n = 30), Klebsiella pneumoniae (n = 10), Proteus mirabilis (n = 15), Proteus vulgaris (n = 10), Pseudomonas aeruginosa (n = 7), Moraxella bovoculi (n = 5), Mannheimia haemolytica (n = 6)) using the spectrophotometric method in the absence of inhibitors and with the introduction of colloidal silver. The obtained results demonstrate the potential possibility of including colloidal silver in a complex of therapeutic and preventive measures to combat pathogens of bronchopneumonia in young cattle that are capable of forming a biofilm.

The purpose of this work was to study the polymorphism of the LipL32 gene of various pathogenic leptospira serovars, as well as to develop a prototype test system for the indication of this gene using the real-time polymerase chain reaction method with an assessment of its stability. The objects of the study were 245 nucleotide sequences of the LipL32 gene of Leptospira interrogans, DNA samples of leptospira serovars Pomona, Grippotyphosa, Canicola, Bataviae and Tarassovi. Based on the results of bioinformatic analysis of 245 nucleotide sequences of the LipL32 gene, it was established that this gene is a highly conserved region of the genome of the causative agent of leptospirosis. To indicate the pathogen under study for this gene by RT-PCR, a marker locus (lipoprotein L32 region) with a size of 173 nucleotide pairs was determined. Within this site, oligonucleotide primers and a probe were developed, which, according to multiple alignment of the amplified locus, turned out to be identical for most of the analyzed nucleotide sequences of the LipL32 L. interrogans gene. BLAST analysis of the sequenced nucleotide sequences of the pathogenic leptospira serovars Pomona, Grippotyphosa, Canicola, Bataviae and Tarassovi showed that the identity of the lipoprotein L32 gene region amplified by engineered oligonucleotides of the above isolates with DNA sequences of the causative agent of leptospirosis stored in the NCBI database ranged from 95.74 to 98.95%. Using the developed oligonucleotides and a fluorescent probe, a prototype test system for the detection of pathogenic leptospires by PCR-RV was constructed. It was found that the specificity of the test kit presented in this work was 100%, and the sensitivity could reach 5·102 copies of DNA per ml of the test material. The stability assessment of the test system showed that the variation coefficients of the minimum threshold values did not exceed 10%, indicating that the kit components were stable during long-term storage.

Despite the rapid development of molecular genetic methods of research, which have literally overturned our understanding of microorganisms, the classical methods of microbiology still do not lose their relevance. Especially it concerns questions when it is necessary to establish the presence of organelles or toxin-forming ability in a bacterium. In the present article the possibilities of visualisation of parasporal bodies on the example of B. thuringiensis by means of Cumassi Brilliant Blue staining are considered. B. thuringiensis strains IPM-3 (H-1), IPM-4 and IPM-4, as well as B. anthracis ∆ Ames strain (negative control) were used in this work. From single colonies of cultures grown on Hottinger's agar, smears were prepared as is customary in laboratory practice, then stained with a mixture consisting of 0.133% Cumassi Brilliant Blue (G) in 50% acetic acid solution and microscoped. Examination of smears showed that the best visualisation of parasporal bodies is achieved when a two-day culture is used, and dye exposure for 30 minutes. In this case visualisation of parasporal bodies in the form of dark-blue structures on the background of light-blue cells and shiny oval spores in all fields of view is achieved. The proposed staining method allows for relatively simple visualization of parasporal bodies and spores, which is especially important when differentiating B. anthracis from other representatives of the Bacillus cereus complex. In addition, visualization of spores in the case of B. anthracis allows for evaluation of the quality of sporulation, making the proposed method a safe competitor to existing ones.

This article presents the results of studies aimed at studying the distribution and assessing the seasonal and age dynamics of the main endoparasitoses of small cattle kept in peasant (farm) households of the Luga, Lomonosovsky and Volosovsky districts of the Leningrad region. Mixed invasions were registered in all the studied farms. The species composition of the parasites included protozoa of the genus Eimeria (E. intricata, E. parva, E. ashata with EI up to 98%); intestinal nematodes (Trichostrongylus sp., Chabertia ovina, Nematodirus sp. with EI up to 96%); cestodes (Moniezia expansa with EI up to 67%); trematodes (Fasciola hepatica with EI up to 28%); protostrongylids (Mullerius capillaris with EI up to 43%). The average EI value was 66.4%. Seasonal and age dynamics of the spread of invasive diseases on the territory of the studied farms were determined. Thus, the peak of eimeriosis and strongylosis was observed in winter, monieziasis - in spring and autumn, mulleriosis - in summer and autumn, fascioliasis - in November. Age dynamics showed that the highest number of eggs of helminths of the suborder Strongylata in a sample of fecal matter from sick animals was found in young animals of the current year of birth (up to 93 eggs / 1 g of fecal matter). At the same time, the highest number of eggs of the cestode M. expansa was noted in breeding rams aged 2 to 4 years (up to 62 eggs / 1 g of fecal matter). High invasion of the trematode F. hepatica was established in ewes aged 2 to 4 years (7 eggs / 1 sample studied). It was also recorded that the greatest release of M. capillaris larvae occurred in 7-month-old ewes. During the helminthological autopsy of sets of internal organs from dead lambs and ewes, the presence of parasitic nematodes of the genus Chabertia (Ch. ovina) was established. In the large intestines, 25-48 specimens/head were found, which amounted to 16.7% of the parasite burden.

The article presents research results on determining the degree of contamination of water samples from different water bodies with taeniid-type eggs, considering zonality and specific ecological conditions for infestation with invasive eggs and helminth larvae. The proximity of rivers, lakes, ponds, ditches, canals, puddles, swamps, and mineral springs to populated areas, as well as their closeness to livestock farming regions and the presence of stray dogs, contributes to the deterioration of the sanitary condition of these territories, where the sanitaryhelminthological factor is a primary concern. A crucial task is conducting water monitoring studies for helminth egg contamination, which will help prevent the entry of invasive eggs and larvae into various aquatic ecosystems. Many scientific sources emphasize the need to develop monitoring methods to assess the sanitary and epidemiological state of various environmental objects related to their contamination. The contamination of various water bodies in the vertical zonation zones of the Republic was assessed using sanitary-parasitological research methods. Water samples were investigated using generally accepted techniques. Monitoring data analysis was carried out using biometric methods, and statistical processing of materials was performed using the "Biometry" computer program. In plain, foothill, and mountain zones, these water bodies, excluding mineral springs, exhibit moderate to high contamination with helminth eggs and larvae during spring, summer, and autumn. Contamination levels were higher in poorly maintained riverbanks adjacent to private homes, gardens, farms, orchards, and other agricultural facilities, posing a sanitary and hygienic threat and risk to animals and the population.

The Baikal seal (Pusa sibirica) is an endemic species to this pond, it feeds exclusively on fish belonging to many species that live both on the surface and at a depth of more than 400 meters in various regions of the lake. Seals are parasitized by both ectoand endoparasites, including cestodes and nematodes of intestinal and pulmonary localization. In addition, seals can be accidental hosts of parasites common to other animal species. The article presents the results of a study of scrapers obtained in helminthological autopsy from the gastrointestinal tract of Baikal seals during the annual scientific research expedition of the Baikal branch of VNIRO to study the abundance, monitoring the territorial distribution and role of Baikal seals in the closed ecosystem of Lake Baikal in the Chivyrkuy Bay in October 2020-2022. The samples were placed in 70% and 96% alcohol in individual test tubes and examined by microscopy and using a compressor. The scrapers identification was made by such features as the shape of the body, the presence and location of the proboscis, the number of hooks on the proboscis (how many rows and how many in one row) and their absence on the body, the size of the parasite, its localization in the body of the Baikal seal. Our research has suggested that the scrapers found in the gastrointestinal tract of the Baikal seal belong to the species Metechinorhynchus truttae, which parasitizes the intestines of fish in Lake Baikal. When eating seals, fish infected with M. truttae, both fish and helminth tissues are digested, which does not affect the welfare of seals.

The aim of this work was to develop and validate a method for the quantitative determination of marbofloxacin in the substance and the medicinal product "Marbotim" in the form of an injection solution using highperformance liquid chromatography. The following tasks were solved in the course of the work: to develop methods for the quantitative determination of marbofloxacin in the substance and medicinal products based on it, to validate the method for the quantitative determination of marbofloxacin in the substance and in the preparation "Marbotim" in the form of an injection solution. The quantitative content of marbofloxacin was determined using high-performance liquid chromatography according to OFS.1.2.1.2.0005 or FEAEC 2.1.2.28 [4]. The work used the analytical standard sample of marbofloxacin series G1297125 (DR. EHRENSTORFER) with the content of the active substance of 99.28%, acetonitrile (Alpha Chemika, India), trifluoroacetic acid (Central Drug House, India), glacial acetic acid (SigmaAldrich, USA) and ultrapurified water obtained using the Rephile Genie U device that produces ultrapure water (type I water) and reverse osmosis water (type III water) (China). Validation was carried out according to OFS.1.1.0012. A 0.1% (vol.) solution of acetic acid was used as a solvent. The standard solution of marbofloxacin, test solutions of marbofloxacin substance and the medicinal product "Marbotim" were prepared using a solvent (0.1% acetic acid solution) and with a final concentration of marbofloxacin - 16 μg / ml. Based on the results of testing for the parameters: specificity, linearity, convergence, intralaboratory precision, accuracy, analytical range, robustness, the methods for the quantitative determination of marbofloxacin in the substance and the medicinal product "Marbotim" in the form of an injection solution were assigned the status "Validated".

The leading place among diseases of non -infectious etiology in productive animals is occupied by diseases of the digestive tract. The article discusses the pathogenetic mechanisms of ulcerative gastroduodenitis development, modern approaches to pharmacotherapy of the disease and prospects for the use of herbal remedies based on oleaster. An analysis of publications by keywords, "oleaster", "pharmacological effects", "herbal remedy", "gastritis", "peptic ulcer disease", "medicinal plants", posted in bibliographic databases and scientific electronic libraries of search engines. The existing pharmacotherapeutic approaches to the treatment of ulcerative gastroduodenitis, including herbal preparations, were studied, and data on biologically active substances contained in narrow-leaved oleaster were searched and analyzed, with an emphasis on their potential therapeutic effect in ulcerative gastroduodenitis. The main pathogenetic factor of peptic ulcer disease is damage to the mucous membrane of the stomach and duodenum under the influence of excessive production of hydrochloric acid and pepsin with the subsequent development of oxidative stress and disruption of its barrier function. Frequent use of non-steroidal antiinflammatory drugs (NSAIDs) for therapeutic purposes in animals contributes to the development of NSAID-induced gastropathy. Modern therapy of ulcerative gastroduodenitis in unproductive animals is based on the use of synthetic drugs - blockers of H+ and H2 - histamine receptors, antacids and sorbents. A promising direction in the therapy of ulcerative gastroduodenitis is the use of herbal preparations with proven gastroprotective activity, such as powder of rhizomes and roots of elecampane, flax seeds, plantain and preparations based on calendula officinalis. As a source of biologically active substances for the production of herbal preparations / feed additives with a gastroprotective effect, it is possible to use raw materials of oleaster - a plant containing a significant number of tannins, flavonoids, carotenoids and alkaloids, aqueous extracts from the fruits of which have wound-healing, antiinflammatory, antimutagenic, antimicrobial properties.

Zearalenone is a mycotoxin produced by fungi, mainly of the genus Fusarium, which is often found in animal feed. Zearalenone is known to have estrogenic activity and can cause various disorders in the reproductive system of animals. In recent years, conjugated forms of zearalenone, such as sulfates and glycosides, have increasingly attracted the attention of researchers. In this regard, the aim of this study was to analyze the embryotoxicity of zearalenone and its conjugated forms when administered to pregnant rats. The article presents an experimental analysis of the embryotoxicity of zearalenone and its conjugated forms (sulfates and glycosides) when administered to pregnant rats. The study was conducted on four groups of animals, including a control group, using crystalline zearalenone and feed extracts naturally contaminated with zearalenone and its conjugates. The results showed that the presence of conjugated forms of zearalenone significantly enhances the embryotoxic effect. This is manifested by an increase in preimplantation embryonic mortality by 25- 30%, an increase in postimplantation mortality by 15-20%, and an overall increase in embryonic mortality of up to 40%. In addition, a decrease in fetal weight by 10-15% and a decrease in craniocaudal size of fetuses by 5-10% were observed in the experiment. These effects are associated with the possible release of toxic zearalenone from conjugated forms in the gastrointestinal tract. This leads to an actually higher toxic load than calculated. Thus, the study results highlight the importance of understanding the potential risks associated with conjugated forms of zearalenone.

The objects of study in this work were the following strains: Pediococcus acidilactici, Lactobacillus johnsonii and Ligilactobacillus salivarius, isolated from the feces of 14-day-old broiler chickens. A sample of broiler chicken feces was placed in a sterile MRS nutrient medium (HiMedia, India) and incubated at 37 ˚C for 24 hours. After that, the analyzed samples were subcultured deeply onto the MRS-agar nutrient medium (SPC Biokompas-S, Russia) using the limiting dilution method to isolate individual colonies of microorganisms. Petri dishes with the cultures were incubated for 48 hours at 37 ˚C. The grown colonies of microorganisms were identified by cultural and morphological characteristics for further sequencing. The resistance of these cultures to bile acids was studied, their antagonistic activity, tolerance to extremely low and high pH values were assessed, and their resistance to different groups of antibiotics was analyzed. L. salivarius was the most resistant to bile compared to L. johnsonii and P. acidilactici. P. acidilactici did not exhibit antagonistic action against the normal microbiota of the gastrointestinal tract, unlike the other analyzed strains, but had a significant effect on opportunistic bacteria. Extremely low and high pH values did not provoke complete death of P. acidilactici, while L. salivarius and L. johnsonii did not retain activity at extremely low pH values. The experiment also revealed that L. johnsonii was the most antibiotic-sensitive strain.

The goal of the present study was to assess the chemotherapeutic effectiveness of moxifloxacin, at various doses, in experimental colibacillosis of chickens. Day-old Hisex Brown chickens were experimentally infected via intraperitoneal injection with Escherichia coli in suspension at a dose of 1.5 x 10^8 CFUs / 0.5 mL per chicken. For the sake of the experiment, we divided the chickens into 3 groups (n=90, in each group). The dose of moxifloxacin for Group I was determined 5 mg/kg body weight, Group II – 10 mg/kg body weight and Group III – 20 mg/kg body weight. In each group the chickens were challenged intraperitoneally once (ten chickens at a time), at 1h, 2h, 3h, 4h, 6h, 8h, 10h, 12h following the challenge and simultaneously with the challenge. The results of our research prove that the therapeutic effectiveness of moxifloxacin at a dose of 5 mg/kg body weight, in experimental colibacillosis, irrespective of the moment of administration of the drug in regard to the moment of the challenge, was insignificant. Moxifloxacin at the dose of 5 mg/kg body weight was just scarcely effective when it was administered to the chickens at 1h and 10h following the challenge and simultaneously with the challenge (total life span = 31 -39%). Otherwise, the specified dose of the drug proved ineffective. When the dose was increased to 10 mg/kg body weight the therapeutic effectiveness of the drug increased likewise. When moxifloxacin was administered to the chickens simultaneously with the challenge the total life span was 57%, thus the dose can be considered effective. Similar results were achieved when the drug was administered to the chickens at 6h, 8h and 10h following the challenge (the total life span was 44-53%). The drug at a dose of 20 mg/kg body weight allowed to achieve higher effectiveness. Moxifloxacin at such dose ensured the total life span from 33% (administration at 12h following the challenge) to 75% (administration simultaneous with the challenge).

The success of disinfection measures in the country depends on the availability of effective drugs to the veterinary industry. For this purpose, new drugs are being researched and tested. According to international regulations, they must be safe, highly effective and comply with generally accepted standards. In the article, the authors present research data aimed at determining the bactericidal activity of the Theotropin P+ disinfectant against the causative agent of brucellosis using the suspension method and the method of neutralizing contaminated surfaces of test objects (rubber, wood, galvanized steel, concrete) that mimic livestock facilities. The reference strain B was used in the work. abortus 54M (test - culture), which was previously studied for its basic properties (tinctorial-morphological and cultural-morphological), cultivated on mowed liveropen-hearth agar with Hottinger's digest (PMHA) and liver-open-hearth broth with Hottinger's digest (PMHB) and the disinfectant "Theotropin P+" in the following concentrations 0.5%; 1%; 2%; 5%; 10% and exposures on test objects, in the first case 10; 30; 60; 120; 180 minutes, in the second – 1; 3; 24 hours. With positive (test culture) and negative (without test culture) controls. Studies have established that the Theotropin P+ product, being a new generation disinfectant, has bactericidal activity against the reference strain B. abortus 54M, the main properties of which are characteristic of this pathogen, ensuring its complete inactivation depending on the type of material of the surfaces to be disinfected. The data obtained allow us to recommend this product as a disinfectant in veterinary practice for disinfection of animal husbandry, infectious foci, transport infrastructure, warehouses, meat and dairy industries, privately and publicly owned, etc.

Conducting preclinical studies is an important stage for the introduction of new pharmacological drugs into clinical practice. A prerequisite for this is to conduct toxicological studies. The article presents the results of studying the parameters of acute toxicity of the new antimycotic drug "Fungicor". The experiments were conducted on laboratory nonlinear white rats and mice. The acute toxicity of the drug was studied with intragastric, subcutaneous and subcutaneous administration. It was found that the dose range of the drug from 4000 to 10000 mg / kg body weight for mice and from 4000 to 12000 mg / kg body weight for rats with intragastric administration did not lead to the death of laboratory animals. The vital signs were within the physiological norm and did not differ from the values of the control animals. The maximum tolerated dose (MTD) of "Fungicor" for mice and rats was 10,000 mg/kg and 12,000 mg/kg body weight, respectively. Subcutaneous administration in doses from 4000 to 8000 mg / kg body weight for mice and from 4000 to 10000 mg / kg body weight for rats also did not reveal a negative effect of the drug on the general condition of experimental animals. The maximum tolerated dose was 8000 mg/ kg and 10000 mg/kg, respectively. When studying the cutaneous toxicity of the drug in doses from 1500 to 15000 mg / kg of body weight, the death of experimental mice and rats was not noted. In connection with the above, it can be concluded that the drug "Fungicor" according to GOST 12.1.007-76 belongs to hazard class IV (low-risk substances).

Fluoroquinolone drugs can affect the cells of the mammalian and avian body. One of the key mechanisms of this effect is the ability of fluoroquinolones to induce oxidative stress by generating reactive oxygen species, which can lead to damage to cellular structures. The study investigated the effects of various concentrations of enrofloxacin on morphometric parameters of erythrocytes from «Hisex Brown» chickens in vitro. Enrofloxacin, a fluoroquinolone antibiotic, exhibits not only antibacterial properties but can also induce oxidative stress leading to cellular structural damage. Blood samples were collected via cardiac puncture and stabilized with heparin. Erythrocytes were incubated in test solutions for 60 seconds, followed by preparation of blood smears on degreased slides. Romanowsky-Giemsa stained smears were used to measure major and minor axes of cells and their nuclei. Changes in erythrocyte volume, surface area, and nuclearcytoplasmic ratio were evaluated following exposure to enrofloxacin at concentrations of 0.05%, 50 μl/l, 5 μl/l, 0.5 μl/l, and 0.3 μl/l. Control groups included erythrocytes in autologous plasma and isotonic saline (0.93% NaCl) without enrofloxacin. Enrofloxacin induced dose-dependent alterations in erythrocyte morphology. The most significant increases in cell volume (>20%) and surface area (14%) were observed at concentrations of 5 μl/l and 0.05%. The therapeutic dose (0.3 μl/l) produced less pronounced changes (11% increase in volume, 7% in surface area). The paradoxical reduction of effect at higher concentration (50 μl/ l) may be attributed to the nonlinear doseresponse toxicity characteristic of fluoroquinolones. The 23% decrease in nuclearcytoplasmic ratio observed at 0.1% and 10 μl/l concentrations was primarily due to cellular swelling.

This document emphasizes the development of feed additives for animals, veterinary drugs, and mineral supplements, supported by the implementation of competitive domestic technologies based on the latest scientific achievements. The goal of this study was to explore the potential use of a biocomposite made from montmorillonite clays and the bacterial strain Bacillus subtilis VKM B-3701D in poultry farming. This biocomposite was tested as a zearalenone mycotoxin neutralizer, as well as a prophylactic and probiotic agent. Zearalenone is a secondary metabolite produced by toxigenic mold fungi, commonly found in contaminated animal feeds, including grains. Even moderate or low levels of zearalenone consumption often led to reduced productivity, such as slower growth rates, decreased production, and lower market quality. These effects frequently occur without clear symptoms of primary mycotoxicosis. The study showed that the biocomposite, when prepared in a 5:1 ratio of bacterial biomass to montmorillonite, reduced the concentration of zearalenone mycotoxin by 6,5 times in vitro experiments, as determined by highperformance liquid chromatography (HPLC). Adding the experimental feed additive to the diet of laying hens at a dosage of 2.0 kg per ton of dry feed increased the average daily weight gain by 5.8% compared to the control group. The average weight per chick reached 3016.9 grams, which is 5.7% higher than the control group. No significant changes in biochemical parameters were observed in either the control or experimental groups. These findings represent an important step toward the development of modern symbiotic feed additives for animals, contributing to the biosafety of domestic poultry farming.

The aim of our research was to study the insecticidal efficacy of the veterinary drug Dironet Plus against ectoparasitosis in cats. Cats were involved in the experiment. Based on the examination and research, the following diagnoses were made: afanipterosis and trichodectosis. After the detection of ectoparasites, the animals were divided into groups. The experiment involved cats of both sexes, different breeds, aged from 14 weeks to 10 years, weighing more than 1 kg. A total of 40 male and female animals were involved in the experiment, for this they were divided into 4 groups of 10 heads each according to the diagnosis. Based on the technical specifications, the animals of the first two groups received the drug Dironet Plus 140 and Dironet Plus 280 in the recommended dose depending on the weight of the animal. The third and fourth groups received the drug Inspector QUADRO TABS (Inspector Quadro Tabs) at the rate of g per kg of body weight of the animal. These drugs were administered to the animals forcibly on the root of the tongue immediately after feeding. On the 2nd, 7th, 14th, 21st, 28th day, a mandatory examination of the test animals was carried out, and then, if the animal continued to remain in the hospital, the examination was carried out once a week. As a result of studies, when using the drug for afanipterosis, Dironet Plus showed 100% effectiveness. During a clinical examination of the animals of the experimental group on the second day after treatment, we found only dead fleas on the body and bedding in the cage. Reinfestation from the 35th to the 45th day from the beginning of the test. In the animals of the experimental group, which were infected with trichodectes after treatment with Dironet Plus, on the second day, 100% death of ectoparasites was also observed. This conclusion was made on the basis of a clinical examination, during which no live parasites were found on the animals’ bodies.

The article presents the results of a study of correlations between the clearance of exogenous sorbitol and the activity of traditional liver enzymes (ALT, AST, ALP) and the level of total bilirubin in clinically healthy cattle. Statistically significant positive correlations have been established between the concentration of sorbitol in blood plasma and the level of AST and alkaline phosphatase, which indicates the promising use of the sorbitol clearance test as an early marker of liver functional disorders. The data obtained substantiate the need for further research to develop new means of preclinical diagnosis of hepatopathy in productive animals. According to the results of the study, there was no statistically significant correlation between the level of sorbitol and the activity of ALT, as well as the concentration of total bilirubin. This may be due to the greater organ specificity of AST for the liver of cattle compared to ALT, as well as the fact that bilirubin levels increase with more serious and pronounced pathologies. The conducted study established the presence of statistically significant strong positive correlations between the concentration of exogenous sorbitol after its loading administration and the activity of key "classical" liver enzymes – AST and ALP in clinically healthy cattle. This indicates that a decrease in the metabolic clearance of sorbitol is closely associated with the initial pathobiochemical shifts characteristic of hepatocyte damage and cholestasis. The results of this study confirm the prospects of using the sorbitol clearance test as a highly sensitive functional test for preclinical diagnosis of liver disorders in cattle.

Medicines make up the majority of xenobiotics, and understanding the processes of pharmaco- and toxicokinetics is prevailing. Also, the question of the influence of the endogenous environment on the biotransformation of drugs, which changes depending on the stage and form of development of all diseases of both infectious and noninfectious etiology, remains open in the literature. The main objective of this study is to study the effect of exogenous cytochrome administration on CYPOR levels in various gastrointestinal pathologies. Five groups of laboratory rats were formed for the study (the studies were approved by the LEC at the FSBEI HE SPbGUVM, protocol No. 2, dated 04/20/2025), weighing 180-195 g, of both sexes, 10 heads per group (males and females were separately). As a result of the studies, we concluded that no reliable differences were found between males and females. All values were within the reference intervals. In induced liver pathologies in experimental animals, an increase in CYPOR levels was observed, which is associated with an increase in endogenous intoxication and increased expression of cytochrome in response to this intoxication, which, within the framework of compensatory mechanisms, also causes increased induction of CYPOR. When induced gastrointestinal pathologies, an insignificant increase in CYPOR was observed, since these pathologies, despite the point of expression of cytochrome, occur without its participation. The introduction of exogenous cytochrome in pathologies significantly increased CYPOR levels. Thus, the results of the study confirm that the introduction of exogenous cytochrome can stimulate CYPOR biosynthesis, especially in liver pathologies, which opens up prospects for further research in the field of pharmacotherapy of liver diseases using cytochromes and CYPOR regulation.

A significant number of CYP450 enzymes of the mammalian body are localized in hepatocytes, which determines the high metabolic capacity of the liver in relation to most foreign substances. Due to the fact that there are no data in the scientific literature on the concentration of CYP450 in the body of laboratory rats depending on the nature of tissue samples, the main goal of our study included studying the variability of the CYPOR concentration level in various biomaterials (blood serum, liver homogenates). Several groups of laboratory rats weighing 180-195 g, of both sexes (n = 20) were formed for the study. At the end of the quarantine, the laboratory rats were humanely euthanized (LEC at the FSBEI HE SPbSUVM, protocol No. 2, dated 04/20/2025) in order to obtain liver homogenate. For this purpose, the samples were placed in a special suspension medium for tissue homogenization (pH=7.4; the basis of the medium is Tris-HCl buffer with the addition of 0.25 M sucrose and a small amount of ethylenediaminetetraacetic acid and sodium salt in order to bind divalent metal ions and glutathione to prevent peroxidation of lipid components. Then, using a homogenizer (Stegler S10, China), 20 homogenate samples were obtained (1 g of tissue per 9 ml of the above medium), which were analyzed by enzyme immunoassay. As a result of the study, the results obtained in the blood serum were statistically unreliable, and amounted to figures in the range from 0 to 470 ng / ml, and often went beyond the sensitivity of the determination method. In the liver homogenates, there was an opposite picture, where the range was from 0.650 to 11.8 ng / ml, the data were representative, reliable.

An important task for the successful development of aquaculture is to increase the resistance of fish to infections in the early stages of ontogenesis, when the immune system has not yet formed. The main protective function is performed by physical barriers: cuticle and mucous membrane, which include antimicrobial peptides and immunoglobulins. The main role in neutralizing harmful microflora is played by the enzyme lysozyme, which has bacteriolytic activity. The purpose of the study is to study the effect of various drugs on the level of antibacterial protection of young sterlet. The study was conducted for 27 days on young sterlet. The fish were divided into 7 groups: control and 6 experimental, receiving various drugs ("Antibak-100", "Sub-Pro", "Ecoflor", "Aquatan", "Roncoleukin" and "Polyphepan"). The drugs were added to the feed according to the instructions. Samples for bacterial contamination analysis were collected on the 7th, 14th, 21st and 27th days. Four individuals from each group were selected for the study. Water was removed from the fish using filter paper and an imprint was made on a solid medium (nutrient fish-peptone agar) in an individual sector. Petri dishes were placed in a thermostat at 26°C for 1 day. Then the number of bacterial colonies in each sector was visually counted. During the study, fluctuations in bacterial contamination were recorded in all the studied groups. The maximum decrease in bacterial contamination was observed on the 14th – 21st days. The lowest number of bacterial colonies on the body of young sterlet was found in the groups receiving the probiotic "Sub-Pro" and the immunomodulator "Roncoleukin". An increase in bacterial contamination was recorded at the end of the experiment. In the last 2 weeks of the experiment, a significantly lower number of colonies was found in all experimental groups compared to the control. The data obtained indicate different duration and effectiveness of the antibacterial action of the drugs used.

The aim of this study was to determine the efficiency of processing by-product of animal husbandry (cattle breeding) – manure obtained from cattle – by biocomposting. Processing of manure in biocomposters "ECO" manufactured by VKO "AlmazAntey", operating from a 380 V electric network, is a modern, environmentally friendly and cost-effective technology. Organic waste of the agro-industrial complex (crop growing, animal husbandry, fish farming) pose a biological threat, contributing to the reproduction of pathogenic microorganisms and the spread of zoonotic infections. Bacteria such as Salmonella spp., E. coli, Listeria monocytogenes can pollute soil, water and agricultural crops. Biowaste also attracts synanthropic animals – carriers of infections. An effective solution is aerobic biocomposting with the participation of thermophilic microorganisms at a temperature of 50 -85 °C. The technology provides multi-stage degradation of the organic substrate, resulting in the formation of a bio-mixture suitable for use as a fertilizer or feed additive, with a volume of 10% of the original. In parallel, the material is disinfected with the deactivation of pathogenic microflora, including antibiotic-resistant strains. In this article, we will tell you how much the mass and volume of manure are reduced due to moisture evaporation, and calculate the energy efficiency of using biocomposter equipment with this technology. The results of field tests have established that when processing a by-product of animal husbandry - cow manure - in the biothermal composter "ECO", its volume and mass are reduced by 75 - 85% of the original. Energy costs for processing 1 kg of a by-product of animal husbandry (cow manure) are about 0.78 kW / h or 3.75 rubles per 1 kg. (The tariff is indicated for institutions in St. Petersburg, in other regions of the Russian Federation tariffs may differ).

This article presents a comprehensive analysis of contemporary approaches for detecting genetically modified organisms (GMOs) in food products, animal feed, and grain, with a specific focus on molecular genetic methods and the regulatory framework within the Russian Federation. The analysis draws upon a review of regulatory acts, scientific publications, and open-source review materials spanning the past decade. The retrospective review concentrated specifically on aspects of GMO detection employing molecular genetic techniques. Analysis of regulatory documents and scientific literature established the legislative foundation governing genetic engineering operations and GMO circulation in Russia. This framework encompasses Federal Law No. 86 (On Genetic Engineering Activities) and Federal Law No. 52 (On Sanitary and Epidemiological Well-being). Furthermore, the study examined definitions pertinent to GMOs and genetically modified (GM)- derived materials, alongside potential risks associated with their application. These risks encompass implications for human health (allergenicity, metabolic effects), the environment (emergence of resistant weeds, genetic contamination), and global security. The review also delineated threshold levels for permissible and non-permissible GM lines in food and feed, as well as requirements for mandatory "GMO" product labeling. Polymerase chain reaction (PCR) is identified as the primary detection methodology. The critical importance of standardizing laboratory procedures, preventing contamination, and implementing stringent quality control measures is emphasized. Consequently, the Russian Federation has established a robust, detailed, and precautionary regulatory system for GMOs. This system integrates rigorous legislative norms, precise control procedures, and standardized high-precision molecular diagnostic methods to ensure product safety.

Contamination of feed with mycotoxins has been a global problem for many decades. The aim of the study was to determine five mycotoxins standardized in feed (aflatoxin B1, ochratoxin A, T-2 toxin, zearalenone, deoxynivalenol) in roughage, succulent, concentrated and other feeds, as well as to identify toxigenic fungi and their metabolites in granulated feeds and raw materials for feed production. A retrospective analysis of the results of feed research in the Omsk Regional Veterinary Laboratory for the period from 2019 to 2024 was carried out for five mycotoxins (aflatoxin B1, T-2 toxin, ochratoxin A, zearalenone, deoxynivalenol). According to the annual reports of the Omsk Regional Veterinary Laboratory, over 7,000 samples were submitted for general feed toxicity testing during the analyzed period (2019- 2024), of which 229 samples were tested for mycotoxins. Wheat, oats, peas, feed corn, coarse (hay, straw) and succulent (haylage, silage) feed, meals, cakes, feed mixtures, and compound feed were subject to mycotoxicological testing. Enzyme-linked immunosorbent assay and high-performance liquid chromatography were used to quantify mycotoxins. The problem of feed contamination with toxigenic fungi and mycotoxins remains relevant even with the use of intensive technologies in crop production and high-tech equipment in feed production. It has been established that the trichothecene group of mycotoxins (T-2 toxin, zearalenone, deoxynivalenol) predominates in roughage and succulent feeds. In raw materials for the production of compound feeds, the growth of mold fungi producing aflatoxins and ochratoxins is more often noted. In most cases, 2-3 or more mycotoxins were detected in one sample, which requires the development of comprehensive measures to prevent combined mycotoxicoses in animals.

Milk is a particularly valuable food product for humans and a number of animals. Recently, it has been recommended to use the clarification for the Holstein breed as black-and-white (in the vast majority of cases) or red-and-white (several percent of animals), since many black-and-white cows are transferred to the black-and-white Holstein breed after genetic analysis. The relative abundance of the remaining dozens of breeds is below this level, but a number of them are important domestic breeds of cows, so they will be considered below. As a result of the data analysis, it follows that both the total and breeding population of the Kholmogory cow breed in Russia is gradually decreasing. At the same time, the average milk yield for the breed per lactation is gradually increasing and already amounts to 7875 kg, which is almost 2 times higher than that for 2005. The average mass fraction of fat is about 3.9%, and the average mass fraction of protein is 3.2%. The four breeds considered (Suksunskaya, Sychevskaya, Tagil breeds and Yakut cattle) are among the smallest ("minor") in Russia, therefore, recently, the prospects for preserving these breeds have caused concern. Although many of the animals of the "minor" breeds are distinguished by an increased content of fat (and / or protein) in milk, acclimatize well in a harsh climate and are resistant to many diseases.

An alternative to scarce animal protein can be proteins of plant origin, in addition, they are considered hypoallergenic, nontoxic and easily digestible. Deep processing of peas allows you to obtain a protein concentrate with a crude protein content of up to 40% and a proportion of essential amino acids of 12.3% of the total protein. The inclusion of pea-based protein in the diet of birds can serve as a replacement for expensive imported soybeans. The experiment studied the effect of feeding feed additives based on extruded soybeans, peas and pea protein concentrate on the physiological state and productive qualities of young chickens. Studies were carried out on chickens (100 heads) of the Dominant breed meat -egg production direction. Control (1) group received commercial compound feed (PC) according to age, 2 group was administered equivalently in protein (up to 5%) pea protein concentrate (MCB) obtained by fermentolysis, 3 group - extruded soybean seeds (ES) and 4 group - extruded pea seeds (EG). Studies showed that young animals of group 2 receiving MCB had the best productivity indicators. Compared to the control, the increase in live weight in this bird on day 40 was 2.7% more (p ≥ 0.05), on day 60 - by 4.7% (p ≥ 0.05), the average absolute and daily increase was 5.4% and 10.2% (p ≥ 0.05). The obtained data are confirmed by the indices of massiveness and shortness, for 2 groups they were the largest and amounted to 5.7 and 53.8, respectively. In this group, the lowest feed consumption per 1 kilogram of live weight gain was noted, and the productivity index was 23 units or 19% higher. Biochemical studies of the blood of birds have established that feed protein additives of plant origin do not have a negative effect on the body of the experimental bird.

In this study, a comparative analysis of the chemical composition of water in three water bodies in the Buinaksk District of the Republic of Dagestan was carried out: The Shura-Ozen River, Lake Buglen-2 and the Kapchugay irrigation canal. The purpose of the work was to comprehensively assess the water quality based on hydrochemical indicators using regulatory requirements for water bodies of fishery importance, as well as to identify the main factors affecting the state of aquatic ecosystems in the region. Water samples were taken at key points of each object, using standard methods for determining the main physicochemical parameters, including acidity (pH), biochemical (BOD5) and chemical (COD) oxygen consumption, total hardness, mineralization (dry residue) and concentrations of the most important ions: ammonium (NH4⁺), nitrites, nitrates, phosphates, sulfates, chlorides, calcium, magnesium, sodium and potassium. The analytical base was supplemented by a comparison of the results with the maximum permissible concentrations (MPC) established by regulatory documents of the Russian Federation (SanPiN 1.2.3685-21 and the order of the Ministry of Agriculture of the Russian Federation No. 552). The results of the analysis indicate a significant anthropogenic impact on the hydrochemical regime of all three water bodies. The most pronounced are the excess of MPC for biogenic elements, organic pollution and mineralization. In particular, the Shura-Ozen River is characterized by extremely high concentrations of ammonium and phosphates (up to 23.9 mg / l and 43.9 mg / l, respectively), which is hundreds of times higher than the standards and indicates severe eutrophication. At the same time, increased biochemical and chemical oxygen consumption is noted, indicating a significant organic loading effect. Recommendations are proposed to strengthen monitoring, identify pollution sources and take measures to improve the ecological state of the studied water bodies.

Today, literacy and correctness of disinfection in service dog breeding are an urgent need. The choice of disinfectant, its concentration, temperature of the solution and the room, the method of application and other indicators play an important role here. The main thing is not to damage the olfactory center of service dogs, otherwise they will lose their search value. This is the purpose of studying the effectiveness of two disinfectants ("Kemisept" and "K-Dez AIR"), when using them in the conditions of the penal system in service dog breeding by irrigating various surfaces (concrete walls and floors, metal grates and wooden pallets). For the study, preliminarily, swabs were obtained from untreated surfaces and it was determined that in the control samples on Endo and XLD-agar media, the growth of enterobacteria colonies was detected, including Escherichia coli in significant quantities; on staphylococcal agar, a large growth of coccal microflora was noted in all samples. In MPA, growth of coccal microflora and spore-forming gram-positive rods Bacillus spp. was detected in all control samples. When treated with Kemisept and K-Dez AIR on intestinal media (Endo and XLDagar media), no growth of enterobacteria colonies was observed in all the studied samples. On staphylococcal agar, a smaller growth of coccal microflora was observed in the studied samples (concrete walls and floor) than in the control samples, and growth of single staphylococcal colonies was also established. Growth of a smaller number of coccal microflora was detected than in the control, growth of only single colonies of coccal microflora was noted. Thus, the results of disinfection of surfaces with two studied disinfectants (Kemisept and K-Dez AIR) are identical, the properties of both can be classified as bacteriostatic in relation to coccal microflora and bactericidal in relation to intestinal microflora.

Structural changes in the distal part of the limbs in cattle are manifested not only by arthrosis of the finger joints, but also by destructive changes in the skin in this area. At the same time, the condition of the hooves and signs of damage to the hoof horn have been described in a number of studies, while the condition of the skin in the interdigital area has not been sufficiently studied at the microscopic level. However, the chronicity of dermatitis and the constant presence of a chronic inflammatory focus undoubtedly have a negative impact on the surrounding tissues and serve as an indicator of changes in the skin in the hoof area. This article presents the results of a study of morphological changes in the skin of dairy cows. The purpose to present data on morphological changes in the skin of the interdigital area in dairy cows with chronic dermatitis. The skin preparations of the interdigital area were studied in the study of the sectional material from 50 cows aged 3 and 4 years, which had signs of chronic interdigital dermatitis, disorders of the growth of the hoof horn, as well as arthrosis of the finger joints. The skin fragments were subjected to histological examination according to the generally accepted methodology. The micropreparations were studied using Jenamed-2 and MicroScreen microscopes. As a result of the conducted research, data was obtained on the variants of microscopic changes in the skin of the interdigital area in dairy cows with chronic dermatitis. It was shown that the process can occur with an allergic component, which should be taken into account when treating sick animals.

The relevance of the topic is determined by the growing scientific interest in the role of photobiological regulation of the processes of embryonic development of poultry. The red spectrum of visible light is able to influence the linear parameters of poultry embryos, the rate of organ formation and metabolism. Optimization of environmental factors, in particular lighting conditions, is becoming an important area of scientific research aimed at increasing the yield of healthy and viable offspring. Artificial egg incubation is widely used in modern farms, but traditional environmental control methods often ignore the influence of the lighting spectrum on the morphological and biochemical aspects of embryo development. Thus, an in-depth study of the effect of the red light spectrum on the growth and development of turkey embryos is relevant for practical implementation in modern technologies of industrial poultry breeding and increasing the economic efficiency of turkey meat production. The purpose of this work is to study the effect of the optical effect of the red spectrum on the linear length parameters of turkey embryos during incubation. The study is devoted to the analysis of the effect of red monochromatic light (wavelength 660 nm) on the growth of turkey embryos during embryonic development from 13 to 27 days. Embryo length measurements were performed on 13, 15, 17, 19, 21, 23, 25 and 27 days of incubation, which made it possible to track the dynamics of length changes under the influence of light exposure. According to the results of the study, it was determined that red monochromatic light had an effect on the length of turkey embryos on the 13th, 15th and 21st days of embryogenesis.

The most important direction in the development of the modern agro-industrial complex is to increase the productivity of farm animals. Animal husbandry researchers are actively searching for effective Russian feed additives capable of regulating digestive processes, metabolism and, as a result, animal productivity. One of the most important tasks of this industry is the development and testing of feed additives. Special attention in scientific research is paid to the development and testing of feed additives based on dehydrated and amino acid-enriched diatomites for piglets. Production tests and physiological experiments were conducted on 900 pigs of LLC Agrofirma Rubezh in the Saratov region. Dehydrated diatomite enriched with natural amino acids "VitaAmin" was added to the diet of animals of the experimental groups, 2 and 3 % of the dry matter of the diet. Hematological and biochemical studies, histological and morphological examinations were carried out at the Vavilov University. Hematological and biochemical studies, histological and morphometric analysis of piglet liver samples were carried out at the Vavilov University. The data obtained indicate that there is no negative effect of the studied additive. It has been established that the use of the supplement leads to normalization of homeostasis and increased metabolism in pigs. This is confirmed by an increase in erythropoiesis, the intensity of protein metabolism, the activity of transamination enzymes, an improvement in liver structure and the morphological state of hepatocytes. The greatest effect was observed when the supplement was fed at a dose of 2% of the total diet.

The article presents anatomical and topographic features of the myofascial formations of the gluteal-femoral region in cattle, which are not reflected in the available literature. It has been shown that the deep femoral fascia between the underlying muscles forms its fascial nodes, from which the "intermuscular fascial plates" extend into the depths, represented by partitions of dense connective tissue passing between the muscles. The deep fascia of the thigh tightly fits the structures of the thigh, and at the same time, the gluteal-biceps, slender and tailor muscles are enclosed between its outer and inner sheets. The outer sheet of the deep fascia, from the lateral surface, covers the tensor of the wide fascia of the thigh, fuses with the surface of the gluteal biceps muscle, and on the border with the semi-tendon muscle it forms a powerful caudo-lateral fascial node. The material for the research was sectional material – pelvic limbs (n=10), selected from calves of the black-and-white Holstein breed, without external signs of pathologies of the musculoskeletal system. The methods of fine macro- and microanatomic preparation under the control of a Micromed HR 350 S binocular magnifier, biomechanical modeling followed by functional analysis of the studied structures, as well as the manufacture of frozen cuts according to N. I. Pirogov were used. It is advisable to use the original data obtained in matters of veterinary and sanitary expertise in the morphological substantiation of the quality of the meat raw materials obtained.

This publication presents the clinical and morphological characteristics of the teeth of dogs with various odontogenic deposits. The research was carried out in the Departments of Animal Diseases and Veterinary and Sanitary Expertise Saratov State University of Genetics, Biotechnology and Engineering by N.I. Vavilov, and in the Department of Animal Anatomy and Histology named after Professor A.F. Klimov at the Moscow State Academy of Veterinary Medicine and Biotechnology – MVA by K.I. Skryabin and Veterinary Clinic «Tsentralnaya na Moskovskaya» (Saratov). The study focused on small-breed dogs with a mesocephalic head shape (n=300), aged between one and ten years. The material used in the study was extracted teeth. A comprehensive methodological approach was used, including a clinical examination of the oral cavity and light microscopy of tooth surfaces. This established that the enamel of the tooth has specific surface formations that occur in a set order. The transition from one state to another depends on processes occurring in the oral cavity, breed characteristics, and feeding and housing conditions. Initially, the tooth is always covered by a biological film, or pellicle, which then transitions to the next state as a result of external factors. These factors can accelerate or slow down this process by altering the balance within the oral cavity. Each dental formation has characteristic features that determine their clear sequence. Of all the acquired enamel formations, the enamel monolith is the most pathogenic, leading to an irreversible odontone state in animals.

Fundamental knowledge about the reproductive system of animals, in particular, anatomical features of the pelvic cavity of pigs, is of particular importance in the context of reproduction. It is the correct anatomical structure and volume of the pelvic cavity that ensure the normal development and functioning of these organs, creating conditions for successful fertilization, pregnancy and subsequent farrowing. Any abnormalities in the development of the pelvis can directly affect the reproductive potential of an animal. Knowledge of the architecture of the venous bed in the pelvic cavity of pigs is of critical practical importance for veterinary medicine. The aim of the study was to establish the age –related features of the course and branching of some veins of the pelvic cavity of Yorkshire pigs, to determine their morphometric parameters and to explain the relationship between the increase in length and diameter of blood vessels in the prenatal and postnatal periods. In the study of two age groups in fetuses and piglets aged 30 days, a significant increase in the linear and volumetric parameters of venous vessels is a direct consequence of the complex adaptation of the vascular system to the new conditions of postnatal life: a radical change in hemodynamics, rapid somatic growth, an increase in the volume of circulating blood and the need to ensure effective venous return in gravity. The predominance of an increase in diameter over an increase in length in almost all vessels emphasizes that the key adaptive mechanism is precisely the expansion of the vessel's lumen to increase its throughput and capacity. In the study of two age groups of piglets aged 30 and 60 days, there is a slight increase in venous vessel parameters, which indicates not a slowdown in development, but a transition from the stage of acute adaptation to the phase of stable and proportional growth, when the vascular system develops smoothly and synchronously with the whole organism.

The prevalence of finger joint pathologies in dairy cattle in conditions of intensive animal husbandry requires the search for a scientifically based approach to the study of diseases of the distal extremities using data from morphological studies. This is necessary to improve methods for the prevention and diagnosis of limb pathologies in cattle and is due to the fact that destructive changes in this anatomical region led to systemic failures in the body and are accompanied by a decrease in animal productivity. However, not all aspects of the pathogenesis of arthrosis of the finger joints in cows are currently studied. The purpose of the work is to provide data on the morphological changes of the sesamoid bones of the 3rd phalanx, their ligaments and bone-ligament connections in cows of the milk direction of productivity. Isolated acropodies from 20 cows of holstinized cows of 4 years old were studied. The sectional material was anatomically dissected, and the hoof joints of the 3 and 4 fingers were examined, focusing on the sesamoid bones of the 3 phalanges. Joint surfaces of sesamoid bones and areas of osseousligamentous connections and proximal and distal ligaments were subjected to histological examination according to a generally accepted technique. Micro preparations were examined using Jenamed-2 and MicroScreen microscopes. As a result of the studies, original data were obtained on destructive changes in the articular surface of the sesamoid bones of the third phalanx, as well as bone-ligament connections and ligaments, which complement the idea of the depth and prevalence of the pathological process in arthrosis of the ungulate joint in cows of the milk direction of productivity.

Leukocyte indices are important tools for assessing the inflammatory reaction, immune response, intoxication and allergization of the body. In this work, we assessed the level of reactivity, intoxication and activity of the inflammatory process in the glandular and connective tissue of cattle in a comparative aspect using leukocyte indices. The object of the study were first-calf heifers and lactating cows of the Holstein breed, which were kept in one of the livestock complexes of the Leningrad Region. The animals were divided into 3 groups: 1st - clinically healthy (n = 20); 2nd - with inflammation of the glandular tissue (n = 20) (catarrhal mastitis); 3rd - with inflammation of the connective tissue (n = 20) (arthritis). The animals of the second group had acute inflammation of the mammary gland with the following clinical signs: increased body temperature to 41C◦, depressed state, enlargement of the affected quarter of the mammary gland, soreness in the area of inflammation, enlargement of the supra-udder lymph node, and when milking, a watery serous secretion with casein clots was released from the affected area. In the group with inflammation of the connective tissue, there were signs of acute arthritis: soreness on palpation, fluctuation in the affected area, swelling of the joint, increased local temperature, lameness. The calculation of leukocyte indices was performed using formulas characterizing the ratio of the content of various forms of leukocytes. The results of calculating leukocyte indices showed activation of innate immune mechanisms, as well as severe intoxication in sick animals of the second group, which confirms the presence of an acute phase reaction accompanying inflammation of the glandular tissue. In animals of the third group, inflammation of the connective tissue was accompanied by severe intoxication and increased allergic readiness of the body. It can be noted that the systemic response of the body to inflammation of the glandular tissue is more intense.

Magnetic resonance imaging (MRI) has proven to be a highly effective non-invasive tool for the study of avian embryogenesis, enabling detailed visualization of internal structures without compromising egg integrity. In this study, MRI was combined with conventional approaches, including candling, anatomical dissection, and radiography, to provide a comprehensive evaluation of duck embryonic development. A total of 60 embryos were monitored daily from day 1 to day 27 of incubation, allowing the identification of key stages of growth and structural differentiation. MRI provided high-resolution three-dimensional images of the vascular system, internal organs, and skeletal structures, with particular sensitivity at later developmental stages. Notably, by day 22, the yolk sac began to retract into the abdominal cavity, and by day 27 the embryo reached complete formation and initiated shell pipping. Comparative analysis demonstrated that each method contributed unique information: ovoscopy allowed rapid assessment of embryo viability, radiography provided clear images of skeletal ossification, while MRI offered superior visualization of soft tissues and dynamic processes in real time. The strong concordance between MRI data and anatomical dissection confirmed the reliability of this technique for continuous, non-destructive monitoring of embryogenesis. The findings highlight the applicability of MRI not only as a fundamental research tool but also as a promising method for optimizing incubation protocols and improving poultry breeding practices. The ability to track organogenesis and morphological changes in vivo provides new opportunities for early detection of developmental abnormalities, assessment of environmental influences, and refinement of incubation management strategies.

This study aims to conduct a comparative analysis of thermoregulatory characteristics in two populations of Yakut horse foals — the Momsky (Arctic region) and Amginsky (Central region) — during the first six months of life. The thermal insulation properties of the coat were assessed using an insulation index (II) based on coat mass, hair density, and hair length. In winter, the II for Momsky foals was 7270.65 (density: 1812 ± 127 hairs/cm²; mass: 0.107 ± 0.0058 g/cm²; hair length: 37.5 ± 0.5 mm; diameter: 57.9 ± 1.31 µm), while the Amginsky foals had an II of 4646.34 (density: 1443 ± 108 hairs/cm²; mass: 0.070 ± 0.0043 g/cm²; hair length: 46.0 ± 0.68 mm). To approximate thermal conductivity (k), values of thermal resistance (R) in the range of 0.8–0.9 ° C·m²·W⁻¹ were used, consistent with data for cold-adapted mammals (Walsberg, 1991; Kvadsheim et al., 1994, among others). Using the formula k = L / R, approximate conductivity values were calculated. The thermal conductivity of the Momsky foals (k = 0.042–0.047 W/m·K) was lower than that of the Amginsky foals (k = 0.051–0.058 W/ m·K), which is attributed to the higher hair density that reduces heat loss. Although Amginsky foals had longer hair, the lower density increased convective loss. Both II and k were adjusted for seasonal variation and hair diameter, confirming that the higher density and optimal diameter in Momsky foals ensure effective thermoregulation even with shorter hair length. Morphologically, Momsky foals were more compact (girth index: 118.9% vs. 112.7%), minimizing heat loss in accordance with Bergmann’s rule. Overall, the findings indicate that the Mom sky population of Yakut horse foals displays more pronounced thermoadaptive traits during the early stages of postnatal development.

Chitosan has a number of characteristics that make it relevant for use in veterinary medicine. It has antibacterial and antifungal properties, which makes it a promising tool for the treatment and prevention of infections in animals. This is especially important in conditions of increasing bacterial resistance to traditional antibiotics. Chitosan accelerates the wound healing process by stimulating fibroblast proliferation and angiogenesis. This makes it a valuable component for veterinary dressings and ointments. It is attractive that chitosan can stimulate the immune system of animals, which is associated with increased resistance to various infectious diseases. This polysaccharide can be used as an additive to animal feed, contributing to improved digestion and absorption of nutrients, as well as lowering cholesterol and triglycerides. According to a number of studies, chitosan and gels based on it are not toxic. Despite the extensive data on the numerous benefits of chitosan, there is insufficient data on potential side effects. There is also limited data on the combined use of chitosan with other drugs. The above indicates the need for further research.

Milk is a very important food product for humans and young animals of some farm animals. The aim of the work is to comparatively study such an integral indicator as the total amount of water-soluble antioxidants (TAWSA) before and after pasteurization of milk of Holstein cows with the analysis of details of these changes and comparison with the biochemical profile. The pasteurization studies were carried out according to industrial technological regulations (at 72°C for 15 seconds) with milk samples of cows of the Ladozhskoye breeding farm. Each of the 6 formed groups included 22 heads of cows, which is enough for statistical analysis. A significant increase in TAWSA values was found in pasteurized milk samples to the maximum values of 24.3 mg/l in group 1 (avg. milk yield 16.6 l) and 25.4 mg/l in group 2 (avg. milk yield 30.2 l); up to 25.9 mg/l in group 3 (MDF 3.50%) and 24.0 mg/l in group 4 (MDF 4.62%); up to 26.0 mg/l in group 5 (MDPt and MDPg 3.09% and 3.24%) and 23.7 mg/l in group 6 (MDPt and MDPg 4.31% and 4.34%) compared to the control before pasteurization. These significant differences are associated (both in our opinion and according to literature data) with a certain degree of protein denaturation and oxidation of milk lipids, which makes a number of functional groups of these milk components more accessible to oxidationreduction processes recorded by the amperometric method as TAWSA. The range of average SCWA values of milk after pasteurization (from 22 to 26 mg/l) can serve as a "reference" interval for practical use. Thus, the analysis of TAWSA changes during pasteurization of cow's milk indicates that the antioxidant activity of milk increases significantly after pasteurization. This is a positive trend for practice in terms of high milk quality after its traditional processing.

The activity of antioxidant enzymes depends on a number of variables, including the content of nutrients in the diet. To normalize the mineral component of diets, it is proposed to use various metal-containing preparations, including chelated (intracomplex) compounds. A number of studies have demonstrated that chelated compounds have greater bioavailability compared to inorganic sources of trace elements.

The aim of the study was to study the effect of the chelate complex on the processes of free radical oxidation in trout by determining the activity of catalase and the content of malonic aldehyde. An organomineral chelate complex (Jupiter LLC, Russia) was investigated. The active base of the mineral supplement is a complex of ethylenediaminediantharic acid and lysine with trace elements (Fe, Mn, Cu, Zn, Co, Se, I). Fish of the experimental groups (n=10) were given the supplement for 30 days; the data were compared with the control (n=10). The chelate complex was administered together with the feed once a day, at a concentration of 0.5 g/ kg (counting from the weight of the feed). The activity of catalase and the concentration of malonic aldehyde in the liver and muscles were determined. The use of organomineral chelate complexes led to a decrease in the content of malondialdehyde in the liver and skeletal muscles. A decrease in lipid peroxidation products was accompanied by a significant increase in catalase activity. The conducted studies suggest that metals in the composition of chelate complexes lead to an increase in the activity of antioxidant enzymes, resulting in a decrease in lipid peroxidation products. Thus, the results obtained serve as an indirect confirmation of the effectiveness of the use of organomineral chelate complexes in industrial aquaculture.

This study conducted a comparative analysis of the species composition, morphometric characteristics, and abundance of rumen ciliate protozoa in three cattle breeds: Yakutian aboriginal, Simmental, and crossbred. Rumen samples were collected via esophageal probe, fixed in 4% or 10% formalin, and analyzed within 6 hours. Ciliate abundance ranged from 535 to 26,500 individuals/mL, influenced by season and feeding type (roughage for Yakutian cattle, mixed rations for Simmental and crossbred). Bacterial concentrations ranged from 100 million to 10 billion/mL. The highest species diversity (36 species, 12 genera) was observed in Yakutian cattle, including 13 breed -specific species, such as the rare Charonina ventriculi and a previously undescribed Metadinium sp., likely due to adaptation to coarse feed and the cow-calf housing system. Simmental cattle exhibited two specific species, while crossbred cattle lacked specific species. Morphometric analysis revealed significant differences in cell sizes among breeds (p<0.001), with Metadinium medium being the largest ciliate (up to 224.2 µm in length) and Entodinium exiguum the smallest (28.3–36.4 µm). Faunal comparisons using the Jaccard-Malyshev coefficient (Kj– m = 0.67) and the Chekanovsky-Sørensen index (Ics = 40%) indicated the greatest differences between Yakutian and Simmental cattle. Probiotic transplantation (biomass with > < 0.001), with Metadinium medium being the largest ciliate (up to 224.2 µm in length) and Entodinium exiguum the smallest (28.3–36.4 µm). Faunal comparisons using the Jaccard-Malyshev coefficient (Kj– m = 0.67) and the Chekanovsky-Sørensen index (Ics = 40%) indicated the greatest differences between Yakutian and Simmental cattle. Probiotic transplantation (biomass with >5,000 ciliates/mL) from healthy Yakutian donors to three Holstein heifers confirmed the method’s efficacy in normalizing digestion, restoring microbiota postantibiotic therapy, preventing gastrointestinal disorders, enhancing feed digestibility, and improving productivity. The method reduced diarrheal episodes and improved nitrogen balance, highlighting its potential in cattle farming.

The multi-chambered stomach of ruminants is a unique digestive system that ensures effective absorption of plant foods through microbial fermentation. The relevance of further research is determined by the need to obtain complex morphometric and physiological data that make it possible to establish the relationship between the structural features of organs and their functional maturity at different stages of ontogenesis. The aim of the study was to evaluate the relationship between the development of the arterial scar in the growth and formation of the pancreatic wall in sheep of the Edilbaevsky breed at different stages of postnatal ontogenesis. To study the structure of the scar wall and its vessels, a complex of modern measures was applied, including various research methods: fine anatomical dissection; micromorphometry; vasorentgenography with a pre-contrasted vascular bed; production of histological preparations with subsequent staining; computed tomography. The sheep corpses were divided into three groups, according to the classification and periodization of animal life according to L.P. Teltsov. The first group: newborn animals (10-14 days); the second group: young animals (5-6 months); the third group: sheep older than 12 months. The presented data convincingly prove the existence of a direct and proportional relationship between the growth and functional differentiation of the membranes of the scar wall and an increase in the diameter of the arteries supplying it, which is a vivid example of the harmonious morphofunctional adaptation of the organ to changing nutritional conditions in ontogenesis. The growth of all metabolically active membranes of the scar (mucosa and muscle) directly correlates with an increase in the diameter of the blood-supplying arteries. The organ does not just increase in size, but its high-quality functional maturation occurs, which is ensured by an abundant blood supply.

Oxidative stress during in vitro maturation of porcine oocytes is one of the factors that reduce viability and exit of competent to insemination female gametes. Exogenous antioxidants, which includes unithiol, reduce production of active oxygen forms in cells. In the present study, pig’s cumulus-oocyte complexes (COC) were cultivated for 44h with and without single-agent at concentrations of 0,42 mg/ml and 0,84 mg/ml. After 22 h was found an increasing (by 21%, p<0,01) of the proportion of COC reinitiated meiosis in oocyte groups cultivated with 0,42 or 0,84 mg/ml of unithiol in comparison with control. After 44h all gametes in experimental groups reinitiated meiosis (85, 83 and 90%). After 44 h, in oocyte group cultivated with 0,42 mg/ ml of unithiol there was a decreasing (by 28%) in proportion of mature cells (p><0,001), and introduction of 0,84 mg/ml of unithiol into environment resulted in a decrease of 31% (p 0,001) in level of cells having completed meiosis compared to control. After 22 h of cultivation, proportion of degenerated cells in a group cultivated with 0,42 mg/ml of unithiol was above control by 14% (p><0,05), and with a concentration of 0,84 mg/ml - by 34% (p><0,001). After 44 h of cultivation, unithiol in concentrations of 0,42 and 0,84 mg/ml continued to initiate degenerative changes in oocytes. Proportion of cells with degeneration was 25 and 32% higher compared to control, p><0,01). Introduction of unithiol in concentrations of 0,84 and 0,42 mg/ml into cultural media caused a decreasing percentage of mature oocytes and increasing level of female gametes with degenerated chromatin. Observed effects of unithiol in studied dosages on meiotic maturation of pig’s in vitro donor oocytes do not allow to recommend it as an exogenous antioxidant for reducing oxidative stress in pig oocytes under in vitro maturation. > < 0,01) of the proportion of COC reinitiated meiosis in oocyte groups cultivated with 0,42 or 0,84 mg/ml of unithiol in comparison with control. After 44h all gametes in experimental groups reinitiated meiosis (85, 83 and 90%). After 44 h, in oocyte group cultivated with 0,42 mg/ ml of unithiol there was a decreasing (by 28%) in proportion of mature cells (p < 0,001), and introduction of 0,84 mg/ml of unithiol into environment resulted in a decrease of 31% (p 0,001) in level of cells having completed meiosis compared to control. After 22 h of cultivation, proportion of degenerated cells in a group cultivated with 0,42 mg/ml of unithiol was above control by 14% (p < 0,05), and with a concentration of 0,84 mg/ml - by 34% (p < 0,001). After 44 h of cultivation, unithiol in concentrations of 0,42 and 0,84 mg/ml continued to initiate degenerative changes in oocytes. Proportion of cells with degeneration was 25 and 32% higher compared to control, p < 0,01). Introduction of unithiol in concentrations of 0,84 and 0,42 mg/ml into cultural media caused a decreasing percentage of mature oocytes and increasing level of female gametes with degenerated chromatin. Observed effects of unithiol in studied dosages on meiotic maturation of pig’s in vitro donor oocytes do not allow to recommend it as an exogenous antioxidant for reducing oxidative stress in pig oocytes under in vitro maturation.

Assessment of the quality of animal donor oocytes and their competence for fertilization is an important task in reproductive biotechnology. Extracellular DNA is one of the promising noninvasive biomarkers that can be used for the above purposes. This indicator is actively being investigated in human-oriented medicine, but its significance in assessing the female gametes of productive animals remains poorly understood. The present study analyzes the content of cDNA in pig follicular fluid aspirated from antral ovarian follicles (diameter 3mm, 3-5mm, < 5mm), analyzes the effect of various centrifugation modes on its isolation, and evaluates the viability of granulosa cells (proportion of cells with pycnotic nuclei). The level of cells in a state of pyknosis was determined by the Tarkovsky method, which included hypotonic treatment with sodium citrate, fixation with an acetic-methanol mixture, and microscopic analysis after Romanovsky–Giemse staining. It was found that the concentration of cDNA in the follicle fluid varies depending on their diameter and mode of centrifugation. With an increase in the acceleration of centrifugation, a decrease in the amount of cDNA and an increase in the proportion of cells with pycnotic nuclei were observed, which indicates their damage. The centrifugation mode (603.72 g for 5 minutes) was identified, providing the maximum level of cDNA content with a minimum number of pycnotic cells. In addition, the data obtained is consistent with the hypothesis that cDNA can serve as an indicator of cellular stress, which is especially important when assessing the quality of biomaterials in vitro. The presented results emphasize the importance of choosing the parameters of centrifugation for the effective isolation of сDNA to further study it as a potential biomarker of oocyte quality and a promising predictive indicator of fertility in productive animals.

Pathological childbirth in highly productive sows is a critical condition associated with high risks for piglets and the mother herself. The purpose of this work was to study the prevalence of pathological childbirth in highly productive sows and to find an effective method of providing assistance in case of labor weakness. The object of the study was a hybrid breeding stock of pigs (large white× landrace) and the offspring obtained from them. The research was conducted on the basis of an industrial pig breeding enterprise. The prevalence of pathological childbirth was studied in 510 repair and basic sows. In order to develop an effective method of obstetric care for weak labor, a comparative assessment of different methods was carried out. Animals were diagnosed with: in the first group, a manual method of delivery was used; in the second group, oxytocin was injected intramuscularly at a dose of 40 ME; in the third group, 20 ME of oxytocin were injected intramuscularly (at the beginning of labor, all sows were injected intramuscularly with calcium borgluconate at a dose of 20 ml); The fourth group was simultaneously injected intramuscularly with 20 ml of calcium borgluconate and 20 ME of oxytocin; the fifth group was injected intramuscularly with calcium borgluconate at a dose of 20 ml and Uterotone with the active ingredient propanolol hydrochloride at a dose of 5 ml. It has been established that the main cause of pathological childbirth in highly productive sows is weak contractions and struggles, as well as the incorrect location of the fetus in relation to the birth canal of the female. The clinically justified and most effective method of correcting labor weakness with an interval between the birth of piglets of more than 30 minutes is combined intramuscular administration of calcium borgluconate at a dose of 20 ml and oxytocin at a dose of 20 ME. This scheme helps to restore the coordinated contractile activity of the myometrium and minimize the risks of perinatal loss of offspring.

Cryopreservation of gametes is an important component of assisted reproductive technology programs. Considering the properties of mesenchymal stem cells (MSCs) and their derivatives, mainly regeneration (due to cytokines, growth factors, exosomes), the aim of this work was to study the use of MSC lysate as a rehabilitation medium for defrosted sperm of breeding bulls. Mesenchymal stem cell (MSC) lysate is a product of MSC destruction containing their biologically active components: proteins, nucleic acids, exosomes, growth factors and metabolites. After thawing, two groups of bull sperm samples were formed: control and experimental, 15 samples each. Samples of the experimental group were mixed with a medium containing MSC lysate, and those of the control group were mixed with phosphate-buffered saline (PBS) in a 1:1 ratio. Sperm quality parameters (motility, morphology) were assessed after 0, 2 and 4 hours of incubation. Due to the sample size, the statistical hypothesis about the difference between the experiment and the control was tested using the Wilcoxon ttest for paired. It was found that four-hour incubation of spermatozoa after thawing in media containing MSC lysate helps to preserve the greatest number of morphologically normal spermatozoa (71.53±3.21%) with the lowest content of head (8.87±1.10%) and tail (18.33±2.27%) defects. Statistically significant differences (p<0.05) were found in the number of progressively motile and immobile spermatozoa at the 4th hour of incubation. The mean value of progressively motile spermatozoa was 1.4 times higher in the experimental group, and the mean number of immobile spermatozoa in the control group was 1.3 times higher. The obtained data prove the prospects of using the MSC component - lysate as a medium for spermatozoa rehabilitation after thawing. However, further research is needed to precisely determine the mechanism of action.> < 0.05) were found in the number of progressively motile and immobile spermatozoa at the 4th hour of incubation. The mean value of progressively motile spermatozoa was 1.4 times higher in the experimental group, and the mean number of immobile spermatozoa in the control group was 1.3 times higher. The obtained data prove the prospects of using the MSC component - lysate as a medium for spermatozoa rehabilitation after thawing. However, further research is needed to precisely determine the mechanism of action.

The STAT3 gene encodes the cytoplasmic protein signal transducer and activator of transcription 3 (STAT3). Currently, based mainly on foreign genome-wide studies, there is information on the association of the gene with energy metabolism, linear dimensions and live weight, but they were carried out mainly on laboratory animals and humans, and there is not enough such information on cattle. Objective: to study the morphofunctional parameters of the mammary gland of Holstein cattle of different genotypes for the STAT3 gene. The work was carried out in 2024-2025 on Holstein cows (n = 26) of Sushchevo, Kostroma Region. In the animals of the sample, the morphofunctional parameters of the mammary gland were assessed, the number of somatic cells (SC) in milk and the genotype for the STAT3 gene were determined. As a result of the research, it was found that the heterozygous genotype STAT3^CT (0.538) had the highest frequency. The clinical form of catarrhal mastitis with a SC of more than 800 thousand cells/ml was registered in animals of the STAT3^CC genotype. Also, the most optimal indicators of morphofunctional parameters of the mammary gland were noted in individuals of the STAT3^CC genotype. At the same time, as a result of the analysis of the case-control model, a statistically significant chance of mastitis occurrence in carriers of the STAT3C allele was determined by 5.6 times compared to carriers of the STAT3^T allele. This should be taken into account when breeding animals and paying attention to their maintenance. To support the hypothesis and increase the objectivity of the proposed conclusions, it is necessary to increase the number of animals in the sample, study these trends in other cattle populations.

The aim of the work was to briefly review the issues of reproduction and adaptation of the Yakut horse to the harsh conditions of the Arctic and Subarctic in the territory of Yakutia. An analysis of studies conducted by scientific institutions of the country on the issues of reproduction and morphological and physiological adaptation of Yakut herd horses to the conditions of the Arctic and Subarctic of northern Siberia over the past 60 years was made. From the brief review of the literature we have reviewed, it is clear that part of the population is exposed to the influence of such negative environmental factors as abnormally severe frosts, shortage of under-snow forage and its low quality, summer heat, etc. It is manifested in a decrease in reproduction rates, in a noticeable depletion of part of the livestock. Alekseev N.D. (2008) put forward a hypothesis of early diagnostics of stress reactivity of horses of the Yakut breed based on the method of determining the number of eosinophils in the blood of animals. He associated this with the occurrence of a stressful state in the body of horses, accompanied by eosinopenia. He suggested that a decrease in the eosinophil index by more than 50% of the initial level should be considered stress sensitivity of the animal. The prevalence of gray color in Yakut horses living in the high latitudes of the Subarctic and Arctic in extremely cold conditions is not the spread of the gray color of the Arabian horse, but an adaptive trait supported by natural selection. The nature of the development of the hair coat in the Yakut horse also belongs to morphological adaptation. The quantity and quality of the hair coat of the Yakut horse in comparison with other breeds were studied very carefully by Alekseev N.D. Part of the Yakut horse population is exposed to the negative factors of the Arctic and Subarctic environment, which is manifested in a decrease in reproduction rates, in a noticeable depletion of part of the herd, thus the method of early diagnostics of stress reactivity of horses of the Yakut breed should be tested on a large herd.

Mastitis is one of the key factors slowing down the growth of milk productivity and worsening the sanitary indicators of milk produced on farms. These diseases can manifest themselves in different periods of the cows' life, including lactation, start-up and dry period, however, they most often occur during the lactation period, when the mammary gland is subjected to significant loads. The research was aimed at analyzing the manifestation of mastitis in dairy cows in the Amur region. The object of the study is highly productive Holstein cows with an average live weight of 600±50 kg. In order to conduct a comprehensive analysis of metabolic processes in lactating cows, two groups of ten animals each were formed. The first group consisted of cows with confirmed subclinical mastitis, while the second group included clinically healthy individuals. The diagnosis of subclinical mastitis was made using the Kenotest express diagnostic kit. The study included an analysis of biochemical parameters of the blood serum of cows with subclinical mastitis. In the cows of the first group with subclinical mastitis, the bilirubin values were increased by 45.5% (p<0.05), cholesterol by 38.7% (p><0.05). In terms of mineral metabolism, an increase in phosphorus by 37.5% (p><0.001) and a decreased calcium level by 13.0% (p><0.05) were noted. Protein metabolism in cows with subclinical mastitis was characterized by a lower level of albumin (by 18.1%, p><0.001). Blood serum levels were measured using a StatFax 1904+R photometer with Vital biochemical reagents. Microsoft Excel was used for statistical processing, calculating the arithmetic mean (M), and the error of the mean (m). > < 0.05), cholesterol by 38.7% (p < 0.05). In terms of mineral metabolism, an increase in phosphorus by 37.5% (p < 0.001) and a decreased calcium level by 13.0% (p < 0.05) were noted. Protein metabolism in cows with subclinical mastitis was characterized by a lower level of albumin (by 18.1%, p < 0.001). Blood serum levels were measured using a StatFax 1904+R photometer with Vital biochemical reagents. Microsoft Excel was used for statistical processing, calculating the arithmetic mean (M), and the error of the mean (m).

The clinical manifestations of purulent endometritis (pyometra) in dogs are diverse and depend on the stage of the process and the degree of cervical openness. There are two main directions in the treatment of dogs with pyometra — operative and medical (conservative). Medical methods are considered organ-preserving and are used only in the case of an open form of pyometra (in animals with open cervix). Complications after conservative treatment include recurrence of the disease in the next estrous cycle. Despite the availability of both surgical and medical treatment methods, the choice of optimal tactics remains a matter of debate, especially in the treatment of breeding and rare animals. The aim of the work was to conduct a comparative analysis of the effectiveness of surgical and medical treatment methods of pyometra in dogs. 44 dogs participated in the study. The animals were divided into two groups. The criteria for the study included: confirmation of the diagnosis "purulent endometritis" based on physical examination, laboratory tests, and diagnostic imaging. The surgical treatment group included 34 dogs that underwent surgical treatment (ovariohysterectomy) after the initial diagnosis of purulent endometritis. The conservative treatment group included 10 dogs. who were treated with aglepristone (the commercial drug Alizin). Six dogs from this group were subsequently operated on due to a recurrence of pyometra. With medical treatment of purulent endometritis, complications occur five times more often than with surgical treatment. During the study, the complication rate was 30.0% for medical treatment and 5.9% for surgical treatment. Medical treatment can be recommended in breeding animals with open cervix and without other uterine and ovarian pathologies, or if dogs are contraindications to surgical treatment.

In recent decades, hoof diseases have continued to cause significant damage to dairy cattle breeding. The most important condition for increasing the productivity and longevity of cows in dairy cattle breeding is effective prevention of hoof diseases and their timely treatment at the very beginning of the disease. A new drug, Fuzogel, has been developed at the Federal Center for Traumatology and Radiology of the Russian Academy of Sciences. The aim of the work was to evaluate the effectiveness of the new import-substituting drug, Fuzogel, in the form of a gel based on the active substances of copper and zinc metal complex compounds, in hoof diseases in cows. The gel form creates a mechanical barrier that prevents the development of infection by reducing the adhesion of vegetative and spore forms of bacteria and fungi to the tissues of the fingers and hooves. Tests of the effectiveness of this product in infectious and non -infectious hoof diseases in cows conducted in two agricultural enterprises indicate its high antimicrobial and anti-inflammatory activity in the initial and moderate severity of hoof lesions, rapid relief of the inflammatory response in such clinical manifestations of diseases as: digital dermatitis, ulcer of the pulp, coronary band, interdigital space vault, pododermatitis. "Fusogel", which does not contain antibiotics, can be used without restrictions on dairy cattle, which allows obtaining high-quality products (milk, meat, offal). After the use of "Fusogel" in cows with mild and moderate severity of the disease, previously detected vegetative forms of bacteria and microscopic fungi were completely absent, which positively affected the regenerative processes and restoration of hoof functions in cows. The high effectiveness of the drug allows its wide implementation in the system of measures to combat hoof diseases in cattle.

In cats with mammary gland cancer, unilateral mastectomy is performed, which requires high-quality analgesia. In accordance with international recommendations, we propose using regional anesthesia methods, in particular, high epidural anesthesia, which is easy to perform, but requires accurate calculation of the volume of local anesthetic. For this, it is necessary to develop a method that takes into account the length of the spinal canal and the degree of distribution along the epidural space in different parts of the cat's spine. The aim of the study was to develop a technique for performing high epidural anesthesia for unilateral mastectomy in cats. Thirty cat cadaver materials and ten live cats were used in the study. As a result of the work, the required blockade area for performing unilateral mastectomy in cats was determined. To control the distribution of fluid, a mixture of Omnipaque radiopaque solution and Ropivacaine local anesthetic were injected into the epidural space, and the contrasting of the epidural space was controlled using X-ray images. The injections were performed stepwise, consistently increasing the total volume of the solution, and changes in contrast were recorded on a series of radiographic images. As a result, an algorithm was developed for calculating the required volume of local anesthetic. To confirm the experimental data on cat cadaver material, clinical trials of the method were conducted on live cats that underwent unilateral mastectomy for medical reasons. In live cats, pain levels were assessed during and after surgery using pain assessment scales. The clinical analgesic capacity of epidural analgesia during unilateral mastectomy in cats was assessed, and its effectiveness for analgesia during surgery was proven.

Anemia is a pathological clinical and hematological syndrome that occurs due to a decrease in the number of red blood cells, which leads to the development of hypoxia of animal organs and tissues [5]. Various pathologies of the red bone marrow, poisoning with zookoumarin derivatives, hereditary hemorrhagic diathesis (hemophilia), oncological and vector-borne diseases, as well as deficiency of vitamins, macro- and microelements can be an etiological factor in the development of anemia in dogs [4,6]. Adequate therapy requires differential diagnosis to rule out the causes of hemolytic anemia. The article presents the results of a study of dogs with signs of hemolytic anemia, which reflect the features of the clinical picture and morphological changes in the blood during the initial visit to the veterinary clinic. Hematological examination made it possible to determine severe anemia (the hematocrit index in the examined animals did not exceed 15.9%). During clinical examination and analysis of anamnestic data, in addition to specific anemia of the mucous membranes, nonspecific symptoms were revealed: lethargy and apathy, hyporexia and/or anorexia in all 100% of dogs. Microscopic examination of blood smears from sick dogs revealed spherocytes, leukemoid reaction (leukocytosis due to neutrophilia), and reticulocytosis with varying degrees of severity in 54% of cases. These changes, taking into account the absence of bone marrow pathologies, oncological, genetic, transmissible and infectious diseases in the studied group of animals, as well as a positive response to immunosuppressive therapy («Prednisolone» and «Mycophenolate» in combination with «Cyclosporine»/ «Azathioprine»/ «Cyclophosphamide»/ «Vincristine»), are more likely to indicate immuno-mediated hemolysis, which corresponds to literary sources [1,2,3,5,6].

The polyfunctionality of the liver causes a wide range of causes for the occurrence of its pathologies, but the mechanisms of sanogenesis reduce the risk of disease development, although hidden, including reversible pathophysiological processes take place, which as a result forms the diversity of manifestations and the need for more detailed diagnostics of hepatopathies. The aim of our research was to study the age dynamics of morbidity and syndromic structure of liver pathology in young pigs. Studies on the structure and dynamics of liver disease in young pigs were conducted at two industrial complexes located in the Voronezh region, where animals of commercial hybrids (KBxLxY) were kept in typical premises and received compound feed corresponding to their age and physiological state. A wide range of indicators was determined in the blood, including markers of hepatopathies (AST, ALT and GGT), reliable changes of which were the reason for a more detailed study of liver functions. Based on the retrospective analysis of the total volume of information, clinically healthy animals (group 1) and those with liver pathology (group 2) were identified. Group 2 included patients with primary detection of liver diseases, which more objectively reflects the incidence rate, since chronic forms of pathology, in addition to the immediate causes of their occurrence, depend on the effectiveness of veterinary measures. The highest incidence of liver disease is observed in the middle of the growing period (45-60 days) and fattening (120-135 days). In the middle of the growing period, hepatitis is more common, the nature of the manifestation of which indicates its origin as a consequence of diseases of the gastrointestinal and / or respiratory tract. At the same time, alimentary risk factors increase the degree of manifestation of hepatopathies, as indicated by the presence of metabolic disorders and moderate accumulation of their toxic products.

The article presents the results of a study of the kinetics of elimination of exogenous sorbitol in urine in clinically healthy cattle animals. Time intervals and quantitative indicators of drug elimination have been established, which is the fundamental basis for the development of a sorbitol tolerance test as a predictor of the functional state of the hepatobiliary system. The results of the work fill the existing gap in data on the metabolism of sugar alcohols in ruminants. The features of the pre-pancreas of cattle inhabited by microbiota capable of fermenting various carbohydrates and sugar alcohols can theoretically influence the absorption processes and subsequent kinetics of sorbitol. However, there is practically no data on the elimination of exogenous sorbitol in cattle in available scientific sources. In connection with the above, the purpose of this study was to study the characteristics of the elimination of orally administered exogenous sorbitol in cattle with an assessment of its urinary excretion to justify further use as a stress test to assess the state of the hepatobiliary system. The results obtained demonstrate that in healthy cattle, exogenous sorbitol begins to be detected in the urine 2 hours after administration, reaches a peak concentration by 4- 6 hours, and is almost completely eliminated within 24 hours. An important conclusion is the presence of statistically significant differences in the level of sorbitol excretion between groups of animals differing in sex, age, physiological status and type of feeding. The observed differences, in particular, higher excretion in bulls compared to heifers and cows, as well as in cows on a highconcentration diet compared to their counterparts on a standard diet, suggest that not only liver function, but also features of cicatricial digestion, hormonal status and metabolic rate can affect sorbitol metabolism in ruminants. This indicates the need to take these factors into account when interpreting load tests.

The aim of our study was to identify histogenetic features of tumor cells and assess their role in the pathomorphological diagnosis of lymphoma. The objects of the study were neoplasms from cats of different ages and sexes. The diagnosis was based on macroscopic examination of the removed tissues and histological examination. When examining histological tissue samples, the tumor localization, growth pattern (diffuse, focal, follicular), tumor cell size (small cell, large cell) and histogenetic characteristics (centroblastic, lymphoblastic, immunoblastic) were taken into account. When analyzing the tumor localization, lymph node involvement was revealed in 17.4% of cases, skin and soft tissues - 15.2%, eyes and eyelids - 6.5%, nasal cavity - 15.2%, gastrointestinal tract - 32.6% and other localizations - 13%. Histological examination showed that the large-cell morphological variant of lymphoma is detected in 65.2% of cases, and the small-cell variant in 34.8% of cases. The most characteristic morphological features of large-cell lymphoma are: diffuse tissue infiltration with atypical cells of round and irregular round shape. The cells are large (up to 10 diameters of an erythrocyte). The cell nuclei are large, contain invaginations and irregularities on the surface. The chromatin pattern in the nucleus is lumpy, which allows differentiating multiple nucleoli. The most characteristic morphological features of small-cell lymphoma are: diffuse or focal tissue infiltration with small (up to 5 diameters of an erythrocyte) lymphoid cells. The cell nuclei are round, contain coarse granular, less often, lumpy chromatin. Nucleoli in nuclei are often not differentiated. The presented data can be used to compile histological classifications of tumors in small domestic animals, as well as to develop new targeted treatment regimens for lymphoma.

The term microbiome encompasses the totality of genes belonging to microorganisms (bacteria, viruses, fungi) that inhabit a particular environment. Sequencing a region of the 16S rRNA gene allows us to study the taxonomic composition of the microbiota, identifying bacteria and archaea, including those that are difficult to cultivate. However, this method still does not have a standardized procedure. The many available methodological options complicate the reproducibility of results and, as a rule, limit the comparability of results between independent studies using different methodologies, measurement and bioinformatics pipelines. Interpretation, discussion and visualization of animal microbiome research results are a complex task due to the lack of uniform standard parameters and reference data for collection and comparison. Standardized methodologies in the study of microorganism communities are needed to simplify and compare the results of different studies. This analysis presents the main reasons for discrepancies in the data obtained at all stages of the work. These include sampling (sampling location, method, sample transport and storage), nucleic acid extraction, 16S rRNA primer selection, amplification, library preparation, sequencing and bioinformatics pipeline. Challenges associated with metagenomic data-based taxonomic and functional profiling include issues of classification accuracy in the face of systematic database errors, difficulties in predicting functions and metabolic interactions in different microbial communities, and the lack of a unified methodological approach to conducting the study. Overcoming these obstacles will require interdisciplinary collaboration, development of computational tools and improvement of analytical methods.