Interleukin-6 is one of the most important pro-inflammatory cytokines, activating the innate and acquired mechanisms of the immune response of animals. The aim of the study was to evaluate interleukin-6 as a biomarker of clinical and subclinical mastitis in dairy cows. For laboratory studies, milk and blood samples were collected from Holstein-Friesian cows with mastitis (n=20) and healthy ones (n=10) in the Novgorod region. The study to study the level of interleukin-6 (IL-6) included animals with infectious cow mastitis caused by Streptococcus spp. The levels of IL-6 in milk from cows with both clinical mastitis and subclinical mastitis compared with the control group at maximum values corresponded to: 1069.47±0.33 pg/ml versus 4004.96±0.25 pg/ml in group with clinical mastitis (CM), p < 0.05; and against 1903.22 pg/ml in the group with subclinical mastitis (SCM), p < 0.05. The levels of IL-6 in the milk of healthy cows were 1066.99±0.33 pg/ml and were significantly lower by 1.7-3.7 times than in the milk of all cows suffering from mastitis caused by Streptococcus spp. A difference was detected in the levels of IL-6 in the blood serum between the results obtained in the group of animals with CM and SCM (1069.47±0.13 pg/ml versus 700.99±0.22 pg/ml). The concentration of IL-6 in the blood serum of healthy cows was in the range of 633.49±0.53 pg/ml and differed from the level of IL-6 in the blood serum of all groups of cows suffering from clinical or subclinical mastitis (700.99±0 .52 pg/ml and 1069.47±0.33 pg/ml, respectively). Our results suggest that cows suffering from mastitis caused by Streptococcus spp. develop a local immune response in the udder in response to the pathogen. Thus, monitoring the level of interleukin-6 in milk may allow early detection of mastitis, which is especially important in cases of subclinical inflammation of the mammary gland.

Mastitis is one of the main problems of dairy farming, causing significant economic damage due to reduced productivity, treatment costs and early culling of sick animals. As a rule, mastitis has a bacterial etiology, occurs both as a mono- and associated infection. We conducted a bacteriological monitoring study of cow milk samples and swabs from milking equipment in an industrial complex for milk production in the Leningrad region. 120 milk samples were examined for clinically expressed (45) and latent mastitis (15), as well as milk samples from healthy cows (30) and swabs from milking equipment (30). 94 isolates of microorganisms were obtained, in which biological properties were established. Susceptibility to antimicrobials was determined to: cephalosporins, carbapenems, aminoglycosides, monobactams, tetracyclines, sulfonamides, quinolones, polymyxins. The etiological factor of the occurrence of mastitis in cows in this farm is the association of coliform microorganisms and Pseudomonas spp. The main pathogen is Klebsiella pneumoniae subsp. pneumoniae. In 36.7% of cases, this is an association of K. pneumoniae and Proteus mirabilis. In 14.4% there was an association of K. pneumoniae and Pseudomonas aeruginosa, in 37% of cases – K.pneumoniae and Escherichia coli, in 11.9% of cases – K. pneumoniae, Staphylococcus aureus and Shewanella spp. Isolates of Shewanella spp. had lecithinase and hemolytic activity, were halophilic and slightly virulent for white mice with subcutaneous infection. Almost all isolated microorganisms were resistant to at least one antimicrobial. Thus, a biocenosis of microorganisms has been formed in this livestock enterprise, which are potential pathogens of purulent-septic diseases, including mastitis. To prevent mastitis disease, comprehensive measures are needed to sanitize livestock premises and equipment in order to eliminate the persistent association of microorganisms in it.

Chlamydial infections in animals are a serious problem spread across many continents. Despite the fact that 22% of the world's countries have reported cases of chlamydial infection in animals, the actual prevalence of this disease may be much higher due to the difficulty of diagnosing it. To date, there is no commercial PCR kit for the detection of Chlamydophila abortus in the Russian Federation. In this regard, the main goal of our study was to conduct a molecular genetic study of the causative agent of chlamydial infection in cattle, using a primer PCR test system developed and optimized by us to detect the genomic DNA of species-specific Chlamydophila abortus. To achieve this goal, we conducted a retrospective analysis of the epizootological situation regarding chlamydial infections of cattle in the territory of 2 constituent entities of the Russian Federation. Molecular biological studies of species identification of causative agents of chlamydial infection in cattle were carried out using commercial PCR kits and an optimized primer system to detect genomic DNA of species-specific Chlamydophila abortus. A retrospective analysis showed that in 2018-2022, “chlamydial infection” was diagnosed in 13.4% of cases. In 51.2% of cases, DNA from the pathogen Chlamydophila pecorum was present; in 19.5% of cases - Chlamydophila abortus, in 29.3% of cases - Chlamydia spp. Molecular genetic studies using an optimized primer test system to identify specific DNA regions of Chlamydophila abortus allowed us to identify the genomes of this pathogen in 34% of cases. DNA from Chlamydophila pecorum and Chlamydophila psittaci was also found in the samples. Most often, Chlamydophila abortus DNA was isolated from cow vaginal swabs - 68.8%, less often from internal organs from dead animals. The developed primer test system is an effective tool for the differential diagnosis of chlamydial infections in cattle, which can provide control over the epizootic situation for this disease.

Infectious bovine keratoconjunctivitis is a highly contagious disease that is widespread in many countries of the world with developed dairy and meat farming, causing great economic damage. This is a contagious disease characterized by lacrimation, hyperemia of conjunctival vessels, photophobia, serous-purulent discharge, opacification and ulceration of the cornea, deformation of the eyeball in the form of keratoglobus or keratoconus, partial or complete loss of vision of the affected eye of the animal. The main causative agents of keratoconjunctivitis are Moraxella bovis and Moraxella bovoculi. Due to the development of multidrug resistance to various antimicrobial chemotherapeutic drugs, there is a need to search for alternative antibacterial agents, which can include bacteriophages. In this work, the goal was to isolate bacteriophages specific to Moraxella bovis and Moraxella bovoculi. For this purpose, 13 samples were selected from a livestock farm in the Moscow region. According to the results of the spot test, two bacteriophages were obtained from the samples, one had specificity only to Moraxella bovoculi, the second had lytic activity as to Moraxella bovoculi, and to Moraxella bovis. The activity according to the Appelman method ranged from 10^-6 and 10^-7 for Moraxella bovoculi and 10^-4 for Moraxella bovis. According to the Grazia method, the yield was 3.2×10⁷ ; 4×10⁶ for M. bovoculi and 2×10⁴ plaque-forming units for M. bovis. The specificity of the lytic spectrum was confirmed in cultures of Pseudomonas aeruginosa, Staphylococcus aureus and Pasteurella multocida.

Ultrasound diagnosis of pathologies of the musculoskeletal system is common in both veterinary and human medicine. This research method allows you to visualize the anatomical structures of the joint to determine pathological changes in individual areas. Caprine arthritis-encephalitis virus is one of the types of infectious agents that affect the condition of joints in goats. Clinical signs are observed mainly in adult goats, but can also occur in young animals as young as 6 months of age. The disease is characterized by long-term asymptomatic virus carriage with the subsequent development of signs of damage to the respiratory system, joints of the limbs and udder, as well as the central nervous system. The article describes the results of ultrasound examinations of the carpal joint of goats of different age groups (from 1 year to 4 years) affected by the goat arthritis-encephalitis virus. According to the results of a clinical examination of the distal thoracic limbs of the studied goats, pathological changes were detected in 75% of animals older than one and a half years. Ultrasound examination visualized tendons, paraarticular tissues, articular surfaces of bones, cartilage, the presence of osteophytes and free chondromic bodies. The main ultrasonographic signs of damage to the articular surfaces and surrounding tissues in goat arthritis-encephalitis were determined, namely the presence of fluid inclusions in the periarticular tissues, thickening of the tendons, cartilage deformation, subchondral surface of the bones and mineralized inclusions. Thus, in animals under the age of one and a half years, signs characteristic of the initial stage of arthrosis were revealed, in the absence of a pronounced clinical picture. Thus, the use of ultrasound will allow early diagnosis of joint lesions in animals at enterprises with goats unaffected by arthritisencephalitis.

Respiratory diseases of birds cause great economic losses to industrial poultry farming. One of the causes of respiratory syndrome is the pathogen Pasteurella multocida. This is dangerous infectious disease characterized by high mortality and affects birds of all species and all ages. Pasteurellosis is widespread all around the world, including of the territory of the Russian Federation. The source of the pathogen is sick and oversick birds. The carriers of the pathogen of pasteurellosis might be rodents, insects, synanthropic birds, as well as animals of other species. The disease most often takes on a stationary character and requires constant epizootic monitoring. Great attention should be paid to the protection of farms from the introduction of the pathogen from the outside. It is necessary to carry out preventive measures in time – disinfection, deratization, disinfection and comply with biosafety requirements when conducting economic activities. For timely diagnosis and prevention, as well as for the successful prevention of the spread and elimination of foci of pasteurellosis, it is necessary to constantly update data on the disease, supplementing them with new information about the pathogen and its spread. For specific disease prevention, it is necessary to use vaccine
The purpose of this article is to analyze the papers of native and foreign authors, which describe the work on the study of the morphology of the pathogen, the causes of the disease, the spread, prevention and control measures against the pathogen of infection. Scientific information and data on the study of avian pasteurellosis, methodological recommendations, regulatory documents of the Russian Federation aimed at diagnosis, prevention and establishment of restrictive measures (quarantine) were used as material for the study.

Animal salmonellosis is an infectious disease affecting a wide range of productive animals. Vaccination of animals is one of the effective ways to combat salmonellosis and remains in demand in veterinary practice. On the territory of the Russian Federation more than 30 vaccines against salmonellosis in animals are used. Conventionally, means of specific immunoprophylaxis against salmonellosis can be divided into two groups: vaccines against avian salmonellosis and vaccines against salmonellosis of other animal species. Production strains are usually derived from isolates isolated from animals in salmonellosis epizootics in the vaccineproducing countries. Inactivated vaccines against avian salmonellosis, represented by preparations, mainly, of foreign manufacturers are made on the basis of cultures obtained from strains of S. Enteritidis, S.Typhimurium and S.Infantis, which corresponds to the etiological structure of animal and human salmonellosis morbidity. Among the means of immunoprophylaxis of salmonellosis in cattle and pigs, used in the territory of the Russian Federation, there are no preparations of foreign manufacturers, and the etiological structure of the disease in these species of animals for many years remains unchanged. Domestic vaccines are developed on the basis of production strains, reference samples of which are deposited in the relevant state collections, the updated list of which is approved by the Order of the Government of the Russian Federation from 06.09.2021 № 2460-r. The majority of vaccines against salmonellosis in animals, excluding birds, used in the territory of the Russian Federation are made on the basis of S. choleraesuis strains. Choleraesuis 370, S. Typhimurium 371 and S. Dublin 373, selected in FGBU "VGNKI", which indicates their sufficient efficiency and epizootic significance at present. 

Antibiotic resistance is a serious problem in the agricultural sector of the economy worldwide. The intestines of animals can be a reservoir for antibiotic resistance genes. The aim of the work was a comparative analysis of the prevalence of antibiotic resistance genes in the intestinal microbiome of cows, broiler chickens and pigs using highthroughput sequencing. The largest number of antibiotic resistance genes was detected in piglets (25 genes). The prevalence of antibiotic resistance genes among broiler chickens and cows was significantly lower, 3 and 1 gene, respectively. Bioinformatics analysis of the sequences established a wide prevalence of resistance genes to tetracyclines (TetW) and aminoglycosides (Aph3-III). Among the carriers of antibiotic resistance genes, species dangerous to animal and human health were identified, including Clostridioides difficile, Streptococcus suis, Trueperella pyogenes, Campylobacter coli, Campylobacter jejuni and Staphylococcus aureus. At the same time, it was established that more than 60% of bacteria in piglet feces possessing the tetracycline resistance gene TetW belonged to the genus Lactobacillus. The detected antibiotic resistance genes in pathogens may pose a threat to the health of livestock due to the ineffectiveness of future antibiotic therapy.

Infectious bursal disease (IBD) is a highly contagious, immunosuppressive viral disease of young birds that causes significant economic losses to the poultry industry worldwide. Vaccination is the most important measure to control IBD. Vector vaccines against this disease (Vaxxitek HVT + IBD, VECTORMUNE® HVT-IBD) are used more and more often in industrial poultry farming. Their peculiarity is the synthesis of VP2 protein of IBD virus, which is the main protective antigen in this disease. Unfortunately, in the Russian Federation there are no domestic kits for the determination of postvaccinal antibody titers for these vaccines, so the development of domestic serologic kits for the VP2 protein of IBD virus is an urgent area of research today. The aim of the present work was to investigate the specificity of recombinant VP2 protein synthesized in a bacterial expression system in diffusion precipitation reaction (DPR). As a result of this research, Escherichia coli strains that synthesize full-length VP2 protein at a concentration of 90 μg/mL were obtained on the basis of FSBEI HE SPbSUVM and FSBEI HE SPbSU. This protein was used as antigen in RDP in diagnostic dilution 1:8 with positive serum of 10 Lohmann Brown cross chickens with antibody titer for IBD virus in ELISA (1:10 000). The precipitation bands in agar gel were shown and the synthesized VP2 protein was found to be specific. The data obtained indicate the effective use of recombinant antigens as components of diagnostic kits.

Currently, one of the significant problems in animal husbandry, including dairy cattle breeding, remains the registration of acute diseases caused by clostridia. This work uses the results of an epizootological survey of an epizootic focus of an infectious disease of cattle and small ruminants in the Alarsky district of the Irkutsk region. Statistical processing of the results was carried out using a standard package of applied programs Microsoft Excel and methods of epizootological analysis. Thermostable microorganisms are sown from biological material, giving intense gas formation on the KittTarozzi medium, which indicates the presence of anaerobic bacteria in the pathological material. In smears of cultures isolated from biological material from dead animals, gram-positive rods with spores located subterminally are detected. The development of the disease in vaccinated animals may indicate both the ineffectiveness of the vaccine (this is confirmed by information from other regions) and the appearance of mutant variants of Clostridium chauvoei. The described epizootological features of the disease manifestation, clinical signs, pathological changes and results of primary laboratory tests allow us to diagnose emphysematous carbuncle. The measures taken by the Veterinary Service of the Irkutsk Region adequately ensure the localization of epizootic foci and the prevention of the spread of the disease beyond the affected area in accordance with the current veterinary regulations. Animal owners are recommended to take measures to improve the maintenance of animals: stopping winter grazing, feeding hay and in farmsteads, prohibiting the removal of unsterilized manure to public areas and grazing. However, these recommendations are not fully implemented due to the prevailing ethnic and cultural aspects of livestock farming.

The objective of our research was to study the features of the colostral immunity formation in the newborns obtained from the cows with different clinical conditions during gestation. The object of the study was Red-Motley cows (n=28) in the third trimester of gestation and the newborn calves obtained from them. Group I – clinically healthy (control, n=8), group II – animals with hepatodystrophy (n=6), group III – animals with a combined course of hepatodystrophy and anemia (n=14). It has been found that in the cows with liver pathology and/or anemia, the colostrum of the first milk yield contains less protein and immunoglobulins by 24.1-25.4% and 11.9-14.2% (P ˂ 0.05), respectively. However, it was noted that in the calves obtained from the cows of group II, the blood serum content of total immunoglobulins after colostrum feeding did not differ from the values of the control group, while in the calves obtained from the cows of group III, the same indicator was lower by 43.0% (P ˂ 0.05). To clarify the reasons for this phenomenon, the Spearman correlation analysis was carried out, which showed that the level of total immunoglobulins in colostrum did not have a significant effect on their amount in the blood serum of calves after colostrum feeding (Rs = 0.40, P ˃ 0.05). In this case, the presence of anemia in calves was of decisive importance (Rs = 0.77, P ˂ 0.05). Thus, the formation of colostral immunity in calves depends not only on the quality of colostrum, but also on the clinical status of the newborn and in particular the presence of a hypoxic and acedotic condition. 

Diphyllobothriosis is a disease caused by natural and social conditions, the causative agent of which is tapeworms of the family Diphyllobothriidae, class Cestoda. Diphyllobothriasis is widespread in the world. It is found in a number of regions of the Russian Federation, including the Volgograd region. The causative agent is tapeworms of the genus Diphyllobothrium spp. The development cycle depends on water bodies, since freshwater copepods are intermediate hosts, and fish are additional hosts. The disease affects people, domestic and wild predators, in particular dogs. The main thing in the treatment of diphyllobothriasis in dogs will be getting rid of intestinal parasites. To destroy helminths, anthelmintic drugs are used, causing the destruction of helminths parasitizing in the body, blocking or suppressing metabolic processes, the muscular and nervous systems. The aim of the study is to conduct a study on the effectiveness of the drug "Prazitel Plus" in dogs with experimental and spontaneous diphyllobothriasis. The effectiveness of the drug "Prazitel Plus" in the form of tablets was determined in veterinary clinics in Volgograd in the period 2023- 2024. The subjects of the study were dogs whose owners complained of loss of animal body weight, general weakness, decreased appetite or refusal of it, vomiting, dull hair, loose stools, and others. The diagnosis was made based on history, clinical examination and laboratory research. Studies have shown that an anthelmintic drug containing praziquantel, pyrantel pamoate and fenbendazole helps kill tapeworms of the genus Diphyllobothrium spp.

The goal of the present article was to study minimal inhibitory concentrations (MIC) of ofloxacin with regard to its efficacy in experimental infection of chicks with Salmonella infantis. Values of MIC of ofloxacin for S. infantis were procured with the help of HiComb Strip test. The results of the tests in vitro, aimed at securing the values of minimal inhibitory concentrations of ofloxacin, prove that the drug boasts high antibacterial activity against most strains of S. infantis. Thus, ofloxacin inhibited the growth of the aforementioned microorganism at concentrations within the interval 0.005 – 0.05 μg/mL. Though one of the isolates proved to be resistant to the drug, its MIC was as high as 1.5 μg/mL. We employed day -old chicks in our experiment, which we conducted in order to evaluate the therapeutic and prophylactic effects of ofloxacin. For the sake of the experiment, we divided 250 chicks in 2 groups with 5 subgroups in either of them (n = 25 in each subgroup). For the experimental infection we used 2 strains of S. infantis, with different minimal inhibitory concentrations of ofloxacin, which had been detected previously. The chicks were challenged intraperitoneally with S. infantis in suspension, incubated on agar medium for 24 hours, at a concentration 3 x 10⁸ CFUs / 0.5 mL. The chicks in Group I were challenged with a strain with minimal inhibitory concentration of ofloxacin 0.05 μg/mL, the chicks in Group II - 1.5 μg/mL. The treatment with ofloxacin started 24 hours prior to the challenge and lasted 5 days. The drug was administered via drinking water ad libitum at concentrations 25 mg/L, 50 mg/L, 100 mg/L, 200 mg/L in both groups. The results of the experiment show that after the challenge of chicks with an S. infantis strain, susceptible to ofloxacin, the drug has high therapeutic and prophylactic effects at concentrations 100 mg/L and 200 mg/L (88 % and 96 % respectively). But in experimental infection of chicks with an S. infantis strain, resistant to ofloxacin, its administration at the above-mentioned concentrations did not lead to positive effect.

Staphylococcosis in chicks raises much concern among poultry industry specialists and improving methods of its containing is still an urgent problem. We conducted a comparative study as for therapeutic and prophylactic efficacy of several fluroquinolone drugs in chicks, experimentally infected with Staphylococcus aureus. The chicks were challenged intraperitoneally with two different field isolates of S. aureus in suspension. One of the two isolates was resistant to fluoroquinolones, the other was susceptible to them. The chicks began receiving the drugs via drinking water ad libitum at 48 h prior to the challenge, at a concentration 200 mg/L. The treatment lasted 5 days. The results of our study show that the highest therapeutic effectiveness (96% and 88%) was achieved in the groups, which had been challenged with an S. aureus strain, susceptible to fluoroquinoloes and treated with enrofloxacin and levofloxacin, respectively. In the group, which had been challenged with a susceptible strain and treated with ciprofloxacin, therapeutic effectiveness was as just high as 68%. The results of our study also show rather low effectiveness of ofloxacin p.o. for treatment of staphylococcosis in chicks. When the chicks had been challenged with an S. aureus strain, resistant to fluoroquinolones, the mortality rate was as high as 96%. When they had been challenged with an S. aureus strain, susceptible to ofloxacin, the mortality rate of the poultry was rather high too - 52%. For most of the chicks in this group the infection became chronic, making the prospects of their treatment and subsequent use in the farm obscure. Administration of norfloxacin proved its low effectiveness, very much like ofloxacin. For the two groups, receiving norfloxacin, the mortality rate among the challenged chicks was as high as 80% and 76%, respectively.

The development and implementation of safe, effective means of preventing and treating diseases of the distal extremities of cattle has important veterinary, zoohygienic and economic significance. At present, the participation of saprophytic and opportunistic microorganisms and their associations in the occurrence and spread of infectious diseases of the fingers and hooves in cattle has been established. An important stage in conducting clinical trials of a new drug is studying the tolerability of its increased doses in all target species of animals for which it is intended according to the instructions. The physiological characteristics of cows associated with the birth of calves and milk production limit the range of effective medicines (antibiotics, NSAIDs, etc.) used for this category of productive animals, which creates certain difficulties in organizing therapeutic and preventive measures. In this regard, a promising direction is the use of a new product “SV” (without restrictions on milk) for dry hoof baths, developed at the Federal State Budgetary Institution “FCTRB -VNIVI” for the prevention and treatment of the initial stages of diseases of the distal limbs of cattle. The results of studying the tolerability of the “SV” product in cows with single and repeated use indicate that the developed product does not have an undesirable negative effect on the clinical status, productivity, hematological, biochemical and pathomorphological parameters of experimental animals. The cows tolerated the effect of the product well; there was no decrease in milk yield and quality of milk, damage to the integrity of the skin and hoof horn, or any allergic reactions. The research results obtained confirm the safety of using the “SV” product for dry baths in practice in the recommended dosage regimen and the prospects for extensive production tests.

The problem of the birth of piglets with hypotrophy in the conditions of modern industrial pig farming causes great economic damage to this industry. Various forms of immunodeficiency are of great importance in the pathogenesis of hypotrophy. In this regard, an active search is underway for effective drugs for veterinary use to combat this pathology. One of these drugs is "Prostimul", which includes a signal peptide of the first type belonging to the cytokine group, as well as vitamins A, E, C. This article describes studies conducted on a group of hypotrophic piglets in order to determine the effect of the drug on immunological blood parameters, namely, an assessment of weasels, helmets, general IG, CEC, CT, SP, ETC. "Prostimuli" were administered twice to a group of hypotrophic piglets, on the first and third days of life in a dose 0.1 ml/kg of body weight. Blood samples for the study were taken on the 1st, 7th, 14th and 21st days. According to the results of the experiment, it was found that the double use of the drug "Stimul" contributed to the normalization of immune functions, which was already visible on the 7th day of the experiment. Thus, in hypotrophic piglets of the experimental group and normotrophics, the indicators of BASK, WEASEL, CEC and general IG were identical. In piglets with hypotrophy treated with the drug "Prostimul", there was a significant increase in the level of Ifn-α expression by days 7 and 14 – by 56.73 times compared with normotrophics. By day 14, an increase in the level of Tgf-β expression was also noted, indicating activation of immune processes in piglets with hypotrophy. Interestingly, by day 21, there was a decrease in the level of Ifn-α expression by 5.33 times compared with normotrophics after using the drug "Prostimul", which may indicate a decrease in inflammatory processes. Two-time use of the drug, in our opinion, should be considered optimal due to its stable effect throughout the experiment.

The aim of the research was to evaluate the effectiveness of the use of various doses of Progestamag® included in the "CoSynch" scheme, as well as in the treatment of ovarian hypofunction. The experimental work was performed in the conditions of the Komi Republic on Ayrshire breed animals. Cows and heifers exhibiting sexual cyclicity with yellow bodies present on the ovaries were selected for synchronization. The efficacy of Progestamag® in the "Co-Synch" scheme was studied in heifers at dosages of 1 and 2 ml, and in cows of 1, 2 and 4 ml. The effectiveness of the drug in correcting gonadal hypofunction was evaluated in lactating cows by intramuscular administration of the drug in doses of 5 and 10 ml. It was found that the maximum fertilization after the first insemination was observed in heifers receiving 1 ml of progestin – 85.7%, whereas in the group without the use of a progesterone-containing drug and in the group where 2 ml of the drug was injected, the indicator was 45.7% lower. The frequency of insemination for pregnancy among heifers treated with the studied drug at a dose of 1 ml was 0.70 and 0.56 lower compared with the control (P≤0.001) and the second (P≤0.05) experimental group, respectively. In cows, against the background of the use of progesterone suspension in the "Co-Synch" scheme, the optimal result was established after the administration of 2 ml of progestin – the frequency of insemination for fertilization was lower by 0.25...1.35 compared with animals of other groups. With ovarian hypofunction, a dosage of 10 ml caused a comparable result obtained against the background of treatment with 2.5% progesterone solution, and the optimal therapeutic effect was revealed in a group of animals receiving 5 ml of the drug. The indicated dosage was characterized by a 0.50...0.69 lower insemination index and a 2.3...2.5 times shorter infertility period (P≤0.05).

The aim of the research was to evaluate the effect of a probiotic drug on metabolic parameters, the microbiome of the digestive tract and the dynamics of body weight gain in calves. To do this, newborn young (n=10) with the first colostrum drink (hereinafter with milk) once a day for two weeks were given 0.5 ml of a probiotic drug containing 10⁷ CFU /ml of Lactobacillus plantarum PL-99, Lactobacillus buchneri BX-99 and Bacillus subtilis BS2017 in a ratio of 1:1:1. The control was animals that had not been given a probiotic drug (n=10). It was shown that against the background of the use of bacterial culture, the content of total protein in blood serum was 10,0% (P<0,05) higher than that of the control group, globulins by 24,8% (P<0,05) alkaline phosphatase activity by 48,8% (P<0,05). The use of probiotics was accompanied by an increase in the total bacterial mass in the intestinal contents (by 1×10^8,44; P≤0,01), including the number of lactobacilli (by 1×10^6,79; P≤0,05), bacteria of the genera Staphylococcus (by 1×10^2,97; P≤0,01), Fusobacterium (by 1×10^7,52; P≤0,05), Clostridium (by 1×10^8,07; P≤0,001), Corynebacterium (by 1×10^5,02; P≤0,01). At the same time, the concentration of microorganisms such as Streptococcus spp, Eubacterium spp, Peptostreptococcus spp, which can cause diseases of the digestive tract, significantly decreased. The use of the biopreparation contributed to a 40% reduction in the occurrence of diarrhea in young animals and an increase in the average daily increase in the first month of cultivation by 36,7 g (P <0,05). Thus, early administration of the probiotic under study during the first two weeks of the neonatal period has a beneficial effect on nitrogen metabolism, the formation of intestinal microbiocenosis and the intensity of body weight gain, as well as a decrease in the incidence of diarrhea in calves. 

The article presents the results of the analysis of the register of feed additives developed for cows, as well as a brief description of the main groups of biologically active substances used in their production. The search for sources was carried out in bibliographic databases, in scientific electronic libraries with search engines: Web of Science (http://www.webofscience.com); Scopus (https:// www.scopus. com); eLIBRARY.RU (https://www.elibrary.ru); Viley Online Library (https:// onlinelibrary.wiley.com); Pubmed (https:// pubmed.ncbi.nlm.nih.gov). Scientific articles in English and Russian were accepted as sources of literature. The names of groups of substances of feed additives were used as keywords. The analysis showed that the Russian market of feed additives is represented mainly by the developments of foreign companies - out of 3696 items, 22.9% are domestic developments, 77.1% are foreign. Feed additives for dairy farming are represented by 1295 product names, which is 35% of the total number. According to the purpose of use, feed additives for cattle are classified into groups: for increasing productivity (energy feed additives, multicomponent feed additives, organic acids and their derivatives, aromatic and flavor feed additives, macro- and microelements and their complex compounds, vitamins and their derivatives, biologically active substances of plant origin containing flavonoids or flavoglycans, essential oils, herbal extracts, herbal extracts, enzymes, prebiotics, biologically active protein substances, amino acids, their salts and compounds), for the safety of young animals (vitamins and their derivatives, 1 energy feed additives, prebiotics, multicomponent feed additives, macro- and microelements and their complex compounds, amino acids, their salts and compounds, biologically active substances of plant origin containing flavonoids or flavoglycans, essential oils, herbal extracts, herbal extracts, organic acids and their derivatives). Most feed additives are designed to improve milk productivity and contain mixtures of fatty acids – 33%, microelements – 25%, vitamins – 21%, plant extracts and essential oils – 10%, microorganisms – 10%, amino acids – 9%, and a complex of organic acids – 8%.

A retrospective analysis of the scientific literature indicates that the predictive potential of caffeine in assessing the safety of the metabolic function of the hepatobiliary system has been actively studied in some animal species (laboratory animals, horses, etc.), but such studies were few in number and ambiguous in terms of obtaining a stable diagnostic result, which allows us to consider further experiments of this kind promising. The main objective of this study is to identify standard pharmacokinetic parameters of caffeine in clinically healthy animals (cattle) for their further use as a starting point for further study of changes in these parameters in various pathologies of the hepatobiliary system. The studies were conducted in 2024 in one of the livestock farms of the Pskov region of the dairy industry; Holsteinized cattle were used in the experiments. In experimental animals pre-treated with exogenous caffeine, after 1, 2, 3, 4, 5, 6, 8, 10, 12, 18 and 24 hours, blood was collected from the experimental animals by venipuncture of the jugular vein, after which caffeine levels were determined by enzyme immunoassay. The obtained data were statistically processed using open software for calculating pharmacokinetic parameters ("distribution volume", "total plasma clearance" and "mean residence time"). The obtained pharmacokinetic parameters, as well as the caffeine levels themselves, will be the starting point for further studies, since in order to identify patterns of change in the behavior of the dynamic clearance test with caffeine, it is necessary to take into account the change in these indicators in a comparative aspect with animals with susceptible hepatopathies.

The ecological role of the zebra mussel is significant and diverse. It plays a significant role in the nutrition of many benthic-eating fish, as well as waterfowl. The settlement of the zebra mussel in the northern regions of Russia has affected the biology of water bodies and had a negative impact on the cooling system of electric and thermal power plants, including nuclear power plants (atomic power plants), etc., causing serious interference in their operation. In the world, a cheap and reliable method of combating this mollusk has not yet been found; mechanical and chemical methods are used. The effectiveness of measures against zebra mussels is currently clearly insufficient and is associated with mechanical and chemical methods. It is believed that there is a lack of a biological component, since the biology of this mollusk has not been sufficiently studied. The gonads of the zebra mussel from the Rybinsk reservoir and the cooling ponds of the Kalinin NPP were examined. The mollusks were collected in the autumn-winter period, when the reservoir was under ice, and the cooling ponds are not covered with ice due to the increased temperature regime. Histological methods were used. The mollusk was fixed in 10% formalin, the thickness of the paraffin sections was 7 μm, stained with iron hematoxylin according to Heidenheim. Studies on the study of the seasonal cycle of the gonads of the zebra mussel showed a change in the seasonal cycle of its gametogenesis in natural reservoirs, whereas with a change in the hydrological regime, which is typical for the cooling ponds of the Kalinin NPP, the seasonal cycle of gametogenesis turned out to be different. Evolution in the new northern homeland of the zebra mussel will go in the direction of growth, adaptation to the habitat. For this, after some time, their stage of post-spawning autumn depletion of the gonads will probably be restored. The time spent on this restoration will be quite long in duration.

Currently, cases of sale of counterfeit dairy products in the retail network have become more frequent, including those containing melamine, which contributes to an increase in protein content. To assess melamine content and detect adulteration in milk and dairy products, accredited laboratories use the method of high-performance liquid chromatography, which is not used in production laboratories due to factors such as auxiliary equipment and chemical reagents. In accordance with TR CU "On the Safety of Milk and Dairy Products", the maximum permissible amount of melamine in milk should not exceed 1 mg/kg. The aim of the study was to identify melamine using infrared spectrometry in the mid-range. The research was carried out in stages at the educational and research center for Food and Animal Feed at St. Petersburg State University of Veterinary Medicine in 2024. The objects of research were raw milk samples without melamine, raw milk samples with different concentrations of melamine and a standard melamine sample. As a result of the studies, a correlation between the intensity of absorption bands in IR spectra of melaminecontaining milk and its concentration was established. Additionally, an absorption band that allows identifying the presence of melamine was found in the IR spectrum.

Water pollution is one of the most serious environmental problems. Industrial waste, agricultural fertilizers and domestic wastewater enter to water bodies, leading to the death of aquatic organisms and deterioration of the quality of drinking water. Particularly dangerous are heavy metals and pesticides, which can accumulate in living organisms, causing chronic diseases and genetic mutations. Solving of these problems requires an integrated approach. It is necessary to develop and implement water purification technologies, improve wastewater collection and processing systems, and introduce methods of the rational use of water in agriculture and industry. This work is based on our own materials, obtained during research es, conducted on Lake Akkel and its tributaries. Oz. Akkel has fresh water and is located in the eastern part of the Buinaksky district. From the data presented it is clear, that water samples, taken in different sites, may differ. For example, a noticeable excess of the concentration of nitrate ion was noted in samples, taken from areas 4 and 5. In other areas no excess on this indicator was observed. On hydrocarbonate ion water samples in points 1, 4-6 had overestimated values. Sample 6 had a particularly noticeable excess of sodium and magnesium cations, exceeding the maximum permissible values in 14 and 54 times, respectively. Water hardness was too high (153,0) at point N. 6. The conducted studies showed, that the water in the studied reservoir is characterized by favorable hydrochemical regime, with the exception of water hardness, a significant excess of which, according to many authors, can negatively effect on the reproduction of aquatic organisms, living in this reservoir. In addition, most aquatic plants are also sensitive to water hardness and prefer softer water environments.

One of the most important tasks of the agro-industrial complex of the Russian Federation at this stage is to solve the problems associated with increasing meat resources, providing the population with high-quality meat products. The development of domestic beef cattle breeding will create conditions for the sustainable development of rural areas, which is one of the most important strategic goals of state policy, the achievement of which will ensure food security, increase the competitiveness of the Russian economy and the well-being of citizens. The article presents the anatomical features of hip flexors (flexors) in a large white breed pig. It has been shown that the main flexor of the hip joint in a pig is the iliolumbar muscle. It is quite fleshy, large, whereas the small lumbar muscle is less developed and is covered by the large lumbar muscle. Among the heads of the iliac muscle, the lateral head is well differentiated on the ventral surface of the iliac bone body, whereas the medial one is represented as a thin, small muscle located between the tendon ends of the large and small lumbar muscles. The material for the research was a sectional material – pelvic limbs (n=10), selected from pigs of a large white breed, without external signs of pathologies of the musculoskeletal system. Methods of fine macro- and microanatomic dissection, biomechanical modeling with subsequent functional analysis of the studied structures were used. New data on the anatomical and topical features of hip flexors in a large white pig are presented, which are determined by the mechanism of the static locomotor act of the animal. The points of fixation of the long and short tendons of the tailor's muscle have been established, which, covering and covering the distal part of the ilio-lumbar muscle from the ventral surface, optionally perform the function of a supporting ligament for this muscle.

There are many tissue barriers in the body, the work of which is largely due to the structure of the vascular wall of the capillary bed. Each of them has its own structural organization, which determines the characteristics of the transport of substances. Many pathologies are caused by a violation of their permeability, associated with changes in the composition of the interstitial medium. That is why the study of the features of the organization of histogematic barrier structures is not only theoretical, but also extremely important in practice. Considering the above, the goal was set to establish the features of the ultrastructural organization of the endothelial cells of the capillaries of the mammalian cerebral cortex, using the example of a domestic bull. The study was carried out using the technique of electron microscopy. The material was fragments of the cerebral cortex of a domestic bull. Their processing for the production of ultrathin sections was carried out according to generally accepted methods. The sections were contrasted with a 2.0% aqueous solution of uranyl acetate and a solution of lead citrate. Photos of ultrathin sections were obtained using the Jem1011 electron microscope (JEOL, Japan) at magnifications of 2500-3000. The terms given in the work correspond to the International Histological Nomenclature. It has been established that the endotheliocytes of the capillaries of the mammalian cerebral cortex are low-profile cells with a polygonal shape. One large spherical core is revealed in their composition. Heterochromatin in the composition of the latter occupies the peripheral zone, due to which its central part remains electron-luminous. A small volume of cytoplasm surrounds the cell nucleus with a thin layer. It contains a small number of organelles and a small number of pinocytic vesicles, which indicates low cell transport activity.

The carcinogenesis of mammary gland tumors in cats is characterized by its uniformity with respect to cellular structures, due to this, it is possible to analyze the effect of individual signature patterns on the mechanism of cancer occurrence well. To do this, it is necessary to determine the functional state of individual proteins that begin to express both inside and on the surface of the nuclear structure. Some multifunctional proteins in the region of nucleolar organizers form the activity of the nucleus, which is closely related to the regulation of the cell cycle. The nucleophosmin protein is an essential cellular protein that is involved in a number of pathways, including mRNA transport, chromatin remodeling, apoptosis, and genome stability. It is poorly expressed by resting cells, but its overexpression leads the cell to stimulate division and increase metastatic potential. Therefore, the aim of our study was to study the expression of the nucleophosmin protein (NPM1) at different histological gradations of tubular carcinoma in mammary glands in cats (n=13). The review presents the results of the histological structure of tubular carcinoma from the highly differentiated to the low-differentiated type. When studying the material, it was revealed that tumor emboli were recorded in 5 samples of G3 tumors in lymphatic vessels that were located cross-border, and macrometastasis, occupying about 70% of the parenchyma of the cortical substance, was also recorded in one sample of the lymph node. When performing an immunohistochemical study (IHC), it was determined that immunopositive sites were noted in the nucleolar localization, while a staining score was recorded, which corresponded to moderate (++) for highly differentiated tumors and strong (+++) for low-grade ones. Thus, when this marker was overexpressed, chromatin disorganization occurred in the nucleolus with an increase in subcomputments in the nucleus, which subsequently led to an increase in the metastatic potential characteristic of G3 tumors.

To date, there are a great many research articles and scientific papers covering kidney problems in the feline family, but only a few of them are devoted to polycystic kidney disease. The study was conducted on the basis of the private veterinary clinic "Zoodoctor" in Simferopol, as well as at the Department of Anatomy and Physiology of Animals of the Institute of Agrotechnological Academy of the Crimean Federal State Educational Institution named after V.I. Vernadsky. The object of this study were cats from 9 months to 13 years of age with an established diagnosis of polycystic kidney disease. The aim of the study was to determine the structural and functional changes in organs and tissues in polycystic kidney disease in cats. The paper analyzes the factors influencing the development of the disease. Comprehensive clinical and structural and functional changes of organs and tissues of cats of various age groups were carried out, as well as morphological abnormalities in the tissues of parenchymal organs of cats at different stages of the disease development were established. The revealed functional and morphological changes observed in polycystic kidney disease in cats allow veterinary specialists to use them for early diagnosis and prevention of the disease. The disease is most often diagnosed in cats aged 3 years and older. Polycystic kidney disease in cats occurs mainly in a chronic form with gradual loss of body weight, lack of appetite, increased blood pressure, loss of elasticity of the skin, increased thirst, polyuria and dehydration. Polycystic kidney disease in domestic cats was characterized by the formation of multiple cysts in the kidneys, the sizes of which ranged from 0.9 cm to 2.5 cm, affecting both the cortical and cerebral substance of the kidneys. Histological examination of cats affected by polycystic kidney disease revealed the proliferation of dense connective tissue around large-sized cysts in the renal parenchyma with stretching of the walls of small cysts, the inner layer of which is represented by the basement membrane of the renal tubules, stretching due to the contents.

The article presents the anatomical features of the flexors of the hip joint in an ordinary domestic cat of the Maine Coon breed, which are absent in the available literature. We have clarified the points of fixation of the large lumbar, iliac, sartorial and scallop muscles. The research was carried out at the Department of Anatomy and Histology of Animals named after Professor A. F. Klimov of the Moscow State Academy of Veterinary Medicine and Biotechnology – MBA named after K.I. Scriabin. The material for the research was a sectional material- pelvic limbs (n=8), selected from a Maine Coon domestic cat, without external signs of musculoskeletal system pathologies. The methods of fine macro- and microanatomic dissection under the control of a binocular magnifier "Micromed HR 350 S" were used, followed by functional analysis of the studied structures and skeletotopic projection of points of attachment of muscle parts. It is shown that in a Maine Coon cat, the flexors of the hip joint include a complex of muscles - the tensor of the wide fascia of the thigh, the iliolumbar, sartorial and scallop muscles. The strainer of the wide fascia of the thigh, fusing in the distal part of the fascia with the deep fascia of the thigh and with the quadriceps femoris muscle, creates a pressor effect on this muscle and helps it to unbend the knee joint. The iliolumbar muscle not only bends the hip joint, but also acts as a joint support, as well as an extensor of the knee joint due to cranial thickening (i.e., concentrations of muscle fibers at the cranial edge of the muscle). It passes from the hip to the shin with a wide distal end, which indicates that its lamellar part, together with a slender muscle, optionally also acts as a flexor of the knee joint.

The article presents morphometric studies of eyeballs and crystalline lens of chicken embryos from the 4th to the 20th day of incubation in rostro-caudal and dorsoventral directions. At early stages of development, slight differences in the diameters of the right and left eyeballs were observed, which gradually decreased, reaching synchronous development by the end of incubation. In the rostro-caudal direction, the size of the right eyeball exceeded the left one by 25% on the 4th day, decreasing to 1.9% by the 20th day. Significant differences were observed on the 16th and 19th day (p<0.05...0.01). In the dorsoventral direction, the difference between the right and left eyeballs was 9.4% on the 6th day, stabilizing at 1.8-1.9% by the 18th-20th day. Significant differences were noted on the 6th (p<0.05) and 18th-20th (p<0.01) days. The lens size in the rostrocaudal direction showed a maximum deviation of 33.3% on the 4th day and a minimum of 5.9% on the 20th day. Significant differences between the right and left lens were found only on the 9th day (p<0.01), 18-19th day (p<0.01) of incubation in the dorsoventral direction the difference between the right and left lens ranged from 7.7% to 25.0% in the early stages (4-9 days), decreasing to 4.2% by the 20th day. No significant differences were found. The studies showed that the sizes of the eyeballs and crystalline lens increased in a regular manner during the incubation period, with the right eye and crystalline lens being slightly larger than the left throughout the developmental period. The size of the lens increased in proportion to the growth of the eyeballs. We noted intensive growth during the transition to the early fruiting stage of development.

The pelvic limbs give the animal a relative springiness of the body, as well as speed of movement when running and various reactions to the environment. The more active the muscle, the more abundant its blood supply should be. Knowledge of the features of the structure and topography of the pelvic limb skeleton is necessary for a veterinarian who performs not only surgical interventions on this area of the body, but also conducts a veterinary and sanitary examination to determine falsification. The cadaverous material for the study was delivered to the Department of Animal Anatomy of the Federal State Budgetary Educational Institution of the Russian Academy of Sciences from the fur farming of the Leningrad Region. The objects for this study were the corpses of the black Pushkin sable breed of two age groups: 15-20 months from birth (puberty) and 36-40 months from birth (puberty) in the amount of 10 pieces in each group. To achieve this task, a set of traditional anatomical research methods was used. As a result of the study, the foot bones of the sable of the Black Pushkin breed, as well as the topographically associated arteries, were determined. The flattened bones of the black Pushkin sable breed are formed by three asymmetric rows (proximal, central, distal) of short bones, which are located between the bones of the shin and metatarsal. The metatarsal bones of these animals are represented by five flattened-elongated welldeveloped tubular bones. Each of the five bones has the following surfaces (dorsal, plantar, medial, lateral). The finger bones (ossa digitorum) of the black Pushkin sable breed are represented by five fingers, each of which consists of three phalanges, except the first. It consists of two phalanges. The main artery supplying the blood to the foot area is the dorsal artery of the foot, which subsequently divides many times, feeding the metatarsal and finger area. These arteries are associated with the bones of the foot area. Each bone, like an artery, has its own anatomical and topographic features that are inherent in martens, due to the way their habitat is.

The work is devoted to the qualitative and quantitative assessment of physical rehabilitation in dogs. The relevance of the study is due to the need for a reliable comprehensive assessment of rehabilitation measures to expand the use of rehabilitation in treatment protocols for dogs. The animals in the experimental group had a history of neuropathies of various etiologies and underwent a course of physical rehabilitation with an assessment of the functions of the neuromuscular apparatus. Quantitative assessment was carried out using an instrumental electrophysiological research method - stimulation electroneuromyography (ENMG). Qualitative assessment of the indicators of statodynamic functions was assessed by the following indicators: the presence and degree of lameness, goniometric indicators of joints, assessment of gait and static postures, quality of the support function of the limbs, quality of reflex reactions. The study showed a reliable change in electrophysiological indicators in neuropathies of various etiologies and, at the same time, in the functions of the neuromuscular apparatus in dogs. At the same time, an improvement in the indicators of statodynamic functions was noted. Such results indicate the presence of a direct correlation between the improvement of statodynamic clinical parameters and the improvement of electrophysiological parameters recorded during the ENMG study. At the same time, the quantitative digital assessment using electroneuromyography is more reliable than the qualitative assessment of statodynamic function parameters, which largely depends on the subjective view of the assessor.

The article presents the results of studies of the histological and ultrastructural characteristics of the quadriceps femoral muscle of broiler chickens of the Smena-9 cross on the 35th day of postembryonic ontogenesis using feed additives (probiotic, prebiotic, sorbent) of domestic production in addition to the basic feeding diet.The work was implemented within the framework of the thematic task plan for the implementation of research works under the state order of the Ministry of Agriculture of the Russian Federation (Agreement No. 082-03-2023-238 dated 30.01.2023) on the topic: "Development of theoretical foundations and methodology for the practical use of morphological criteria in assessing the quality and safety of poultry products." It has been shown that against the background of the use of feed additives, an increase in the weight of chickens occurs. At the same time, the microstructure of the rectus head of the quadriceps femoris of birds of the control and experimental groups, while maintaining the general plan of structure (the presence of muscular and connective tissue components, bundle organization), is not the same. Based on studies using light and transmission electron microscopy, it was shown that the signs of morphological maturity of skeletal muscle tissue are most pronounced when using a probiotic, in the case of using a prebiotic and a sorbent, muscle fibers grow less synchronously, which is manifested by the variability of their thickness. The thickness of muscle fibers, their bundles, the state of the mitochondrial apparatus, the packing density of myofibrils and their thickness, the degree of development of endomysium and perimysium and the presence of white adipose tissue can be objective morphological and morphometric criteria for assessing the condition of muscle tissue, which correlates with the taste qualities of poultry meat. Data on the structural organization of the quadriceps muscle of the new domestic cross expand the theoretical base in the field of the myology of farm birds, including in terms of identifying morphological signs of the realization of genetic potential against the background of the use of different feeding diets in chicken rearing technology, which allows us to quickly assess the effectiveness of chicken rearing technology and predict an increase in productivity.

Degenerative-dystrophic alteration in the spine (DDAS) is a chronic progressive pathology characterized by changes in the intervertebral discs, joints, ligaments, and bone tissue of the vertebrae; manifested by severe orthopedic, neurological and visceral disorders. Obtaining and comprehensively studying animal models of DDAS is important for the development of methods for the prevention and treatment of this pathology in humans. An ideal animal model of DDAS should have morphological manifestations and biomechanical characteristics similar to humans. Monkeys are the only species of experimental animals that are closest to humans in their anatomical, physiological and genetic characteristics; they are considered «laboratory doubles» of humans and are of particular interest to researchers. The monkeys are very similar to humans in the structure of the spine and motor behavior. Our results indicate a great similarity of degenerative-dystrophic processes in the spine in monkeys and in humans. Monkeys are susceptible to degenerative-dystrophic processes in all parts of the spine (even in the caudal region), despite pronograde statics and the absence of vertical loads. The development of DDAS in monkeys is age dependent, as is the case in humans: most monkeys with such lesions are adults or geriatric animals. The frequency of detection of DDAS based on autopsy results (our own data) and similar pathological changes in the spine at macroand microscopic levels indicate the possibility of using the monkey species we studied as a natural model for studying similar pathology in humans.

Rational and efficient feeding of aquaculture objects is one of the foundations of production in highly productive fish farming. The aim of the study was to compare the composition of production compound feeds for aquaculture objects and to study the effect of compound feeds on the biochemical parameters of the blood serum of rainbow trout. To achieve the aim of the study, 10 groups of rainbow trout (Parasalmo mykiss (Walbaum, 1792) of the "Rofor" breed) grown in production conditions of cage farms in Karelia were selected. Alanine transferase, aspartate aminotransferase, alkaline phosphatase, total protein, albumins, creatinine, urea, glucose, total bilirubin and total cholesterol were determined in the blood serum of the studied individuals. The obtained result has an important practical significance since with excessive intake of carbohydrates these fish develop liver glycogen overload syndrome due to insufficient insulin production. Therefore, the optimal carbohydrate content for them is 20-30%, including 5-6% fiber. In this case, monosaccharides are used better - glucose, fructose, mannose, somewhat worse - disaccharides and starch, and cellulose is broken down only by 10-20% of the consumed. In addition, it is necessary to take into account that trout, as a cold-loving fish, cannot use carbohydrates in the same volume as heat-loving objects of aquaculture, therefore, in order to save protein, which can be used for energy purposes, it is necessary to additionally introduce fats into their diets. However, in the studied compound feeds this component did not meet the GOST standards. The results of the conducted research can be used to optimize the composition of production feed for rainbow trout and to register background ichthyohematological criteria for the quality of keeping highly productive aquaculture species.

The nutritional value of fish depends on the conditions of keeping and feeding. Rational feeding should meet the needs of fish in organic and mineral components. The enrichment of fish diets with minerals rationalizes economic activities in industrial aquaculture and contributes to the production of high-quality fish products. Obtaining products enriched with trace elements is possible by adding organomineral chelate complexes to the diet. The aim of the study was to determine the content of iron, copper, zinc, cobalt, manganese and selenium in the skeletal muscle tissue of fish by atomic absorption spectrometry when feeding feed enriched with organomineral chelate complexes. The experiment was carried out for a month. The object of the study was fingerlings (0+) of rainbow trout (Oncorhynchus mykiss) contained in fisheries in the Leningrad region. The experimental (n=10) and control (n=10) groups were formed by the method of analog pairs. The content of iron (GOST R 56372- 2015), copper (GOST R 56372- 2015), zinc (GOST R 56372- 2015), cobalt (GOST R 56372- 2015), manganese (GOST 32343-2013) and selenium (GOST 31651-2012) were determined in muscle tissue using the MGA-1000 atomic absorption spectrometer (Lumex, Russia). The reliability of the differences between the samples of the experimental and control groups was assessed using the Student's ttest using the Microsoft Excel 2010 application (Microsoft Corp, USA). The differences were considered significant at p≥0.05. The study showed that feeding feed enriched with organomineral chelate complexes can significantly increase the content of copper, zinc and selenium in the muscle tissue of fish. An increase in the content of elements in muscle tissue indicates that the use of chelate complexes contributes to an increase in the nutritional value of fish products. Based on the data obtained, the chelate complex can be recommended for use in industrial aquaculture. 

Amino acids (AA) are the important markers of the state of protein metabolism, and therefore the study of the amino acid composition of animal tissues is an urgent task. This article presents the results of amino acid analysis of the blood serum of fattening pigs of the Landrace breed and twobreed hybrids (Landrace·Large White) depending on the duration of fattening. Fattening pigs (n=40) were divided into 6 groups depending on the breed and duration of fattening: A-2 – 60 days of fattening Landrace pigs, B-2 – 60 days of fattening F1 Landrace Large White, C-2 – 70- 80 days of fattening a Landrace pig, D-2 – 70-80 days of fattening F1 Landrace Large White, F-2 – 100 days of fattening a Landrace pig, S-2 – 100 days fattening F1 Landrace Large White. The most stable amino acids in blood levels are tyrosine, histidine, threonine, phenylalanine, glycine and proline in all studied groups of animals. According to the results obtained, changes in the AA composition of blood serum are largely due to the duration of fattening (as a one of the key feed factors) and the genotypes of animals. 

Amino acid parameters provide important and relevant data for objective assessment of physiological and biochemical status of organism and patterns of formation of economically useful traits of animals. The objective of this work is to model phenotypic and genetic patterns of variability of main amino acid parameters of blood of pig hybrids within the framework of mixed equation model. Main 19 amino acid parameters of blood serum of 58 heads of three-breed hybrids (Large White × Landrace × Duroc) were obtained and studied: content (g/100 ml) of aspartic acid and its amide (ASP+ ASN) was 0.64; glutamic acid and its amide (GLU+GLN) ‒ 1.04; alanine (ALA) – 0.46; glycine (GLY) – 0.28; threonine (THR) – 0.34, serine (SER) – 0.39; cysteine (CYS) – 0.21; methionine (MET) –0.07; valine (VAL) – 0.52; isoleucine (ILE) – 0.28; leucine (LEU) –0.83; tyrosine (TYR) – 0.46; phenylalanine (PHE – 0.50); histidine (HIS) – 0.31; lysine (LYS) – 0.69; arginine (ARG) – 0.51; proline (PRO) – 0.41. To calculate the correlation values, covariance and variance of features, models using the REMLF90 programs were fulfilled. It was shown that all amino acids have moderate and strong both phenotypic and genetic correlations (r> 0.5). All amino acids have a fairly close connection with the main biochemical indices. From the above, we can conclude that the equation of the mixed model allows us to obtain a deep understanding of the nature of the variability of the main amino acid indices of the blood, connected in a complex labile biochemical system.

A study of the contents of the gastrointestinal tract of the wild snow sheep in different regions of Yakutia revealed a significant diversity of endobiont infusoria, which play an important role in the digestion of this animal. Twelve species of infusoria belonging to the genera Entodinium, Eudiplodinium, Polyplastron, Metadinium, and Ophryoscolex were identified, including three new species distinguished by their morphology and description. The symbiotic fauna varied depending on the geographical location of the snow sheep populations; for example, 11 species were found in the Eveno-Bytantay ulus and 7 in the Oymyakon ulus, with seven species being common to both populations.
An interesting observation is that the efficiency of snow sheep digestion directly depends on the fermentative activity of specific infusoria species, similar to other large herbivorous animals in Yakutia. Infusoria demonstrate the ability to survive for extended periods in winter conditions, which is crucial for digesting coarse plant food available in this harsh environment.
This study emphasizes the importance of the interaction between microorganisms and their hosts for optimizing digestion and survival in the extreme Siberian climate. Further research in this direction could significantly contribute not only to the preservation of biodiversity but also to the development of new approaches in veterinary medicine and ecology.
The discovery of three new species of infusoria aims to enrich the database of microorganisms and may represent an important step toward understanding biological adaptations to the harsh conditions of Yakutia. Understanding this interaction may have long-term implications for the management of wild animal populations, especially in the context of climate change and biodiversity conservation.

The reproductive performance of sows depends partly on the fertility of the boar. Many factors influence the fertility of the boar: external (environment) and internal (genetics). Acceleration of growth of young pigs occurs, as a rule, due to genetic improvements. The article presents the results of studies of sexual development and fertilizing ability of boars of three imported breeds (Landrace, Yorkshire and Duroc). Boars reach sexual maturity at 7-8 months of age, although they reach their full reproductive potential at an older age. One of the most important reasons for the different ability of breeding boars to inseminate with sperm is genetic differences, primarily breed differences. Therefore, conducting research to study the dynamics of ejaculate parameters associated with sexual development in young boars of imported breeds is relevant. In this article, we assessed the rate at which boars reach full breeding maturity and their fertilizing ability by analyzing the parameters of ejaculates with age. After sampling, the ejaculate volume, sperm concentration and percentage of progressively motile sperm were taken into account. The physical parameters of the ejaculate change with the age of the boar. The dynamics of age-related changes in the physical parameters of ejaculates in Duroc boars is significantly lower compared to the Landrace and Yorkshire boar breeds. Duroc boars have better sexual development and differ from Landrace and Yorkshire boars, which are characterized by an earlier cessation of growth. Duroc boars reached their peak ejaculation 6 months earlier than Landrace and Yorkshire boars, at 23 -24 months of age. The most favorable course of sexual development was observed in Landrace boars. Both the volume of ejaculate and the number and motility of sperm in this breed dynamically increased with age. Regardless of the age of the animal, it was possible to prepare a larger number of spemodoses from the ejaculates of boars of a given breed, in contrast to analogues of other breeds.

In conditions of environmental distress and high anthropogenic load in agricultural activities, the task of maintaining the integrity of the animal genome arises. One way to solve this problem is to use drugs that have an antimutagenic effect. Pharmaceutical substances obtained from animal tissues are promising components of such drugs due to their antioxidant and radioprotective effects. In this regard, the purpose of this work was to study the genoprotective effect of hydrophilic cryofraction of the placenta (HCPC) and its mixture with hydrophilic cryofraction of the spleen of cattle (HCSPC) in mice with cytogenetic instability induced by the genotoxicant - mitomycin C (MMC). The genoprotective effect of the studied substances was assessed by reducing the frequency of micronuclei of polychromatophilic erythrocytes (MNPCE) in the bone marrow of mice after administration of MMC. The amount of damage in mitochondrial DNA (mtDNA) in mouse liver was also determined using quantitative polymerase chain reaction. As a result of the studies, it was established that HCPC and HCSPC did not exhibit toxic, mutagenic or DNA-damaging effects. A course of administration of HCPC and HCSPC caused a decrease in the frequency of MNPCE in the bone marrow of mice, with induced cytogenetic instability by 38.8 and 42.3% (p<0.05), relative to animals that were administered only MMC. With a course of administration of HCPC and HCSPC to mice that received MMC, a tendency was found to reduce the amount of mtDNA damage in the liver of mice. Thus, with a course of administration of HCSPC, a decrease in the amount of mtDNA damage was observed by 48.0% and 32.4% in two mtDNA fragments, respectively, relative to mice that were administered only MMC. Thus, with a course of administration of HCSPC, the tendency towards a DNAprotective effect was more pronounced relative to HCPC. These data indicate that HCPC and HCSPC have antimutagenic and DNA protective effects, which are more pronounced by HCSPC, probably due to the high antioxidant effect.

For the first time in Russia a mathematical analysis of sperm production of Kholmogory stud bulls will be performed based on a linear equation model. The aim of the research was to evaluate the parameters of variability of the productivity of Kholmogory stud bulls based on a linear equation model. The object of the study was Kholmogory stud bulls (n = 72) born and used mainly in the Komi Republic. The main aspects of sperm productivity that were the subject of the study include the following parameters: "proportion of live sperm", "sperm concentration", "proportion of sperm with PPD, (%)", "number of sperm with PPD in a dose", "number of sperm with intact acrosome", "number of sperm with abnormal morphology", "sperm survival at 38°C, h". The collected data were analyzed using a mixed equation model approach with the REMLF90 restricted maximum likelihood program. The highest values of the genetic correlation coefficient were found for such sperm production parameters as "sperm concentration, million/ml" - it was reliably positively associated with "the number of sperm with PPD in a dose, million" and "the number of sperm with an intact acrosome, %". In this case, the correlations were at the level of r=0.6-0.8. "The number of sperm with abnormal morphology, %" positively correlated with "the proportion of live sperm, %" and with the "sperm survival at 38°C" parameter. Negatively strong reliable relationships were not established either for the values of genetic or paratypic correlations. Low heritability of sperm productivity parameters (0.039…0.112) indicates that the influence of genetics on these parameters is small. Among these parameters, the highest heritability coefficient was demonstrated by the parameter “sperm survival at 38°C” (0.322). In light of the analysis of sperm productivity as a complex of parameters, it can be stated that this system demonstrates significant stability and variability, which emphasizes the importance of taking into account various aspects when assessing sperm productivity.

In the Republic of Dagestan, where livestock farming is a key area, dairy cattle breeds such as Red Steppe and Caucasian Brown have not been studied in terms of genetic identification. Variations in the PIT1, PRL and GH genes associated with milk productivity can provide important insights into the adaptation of these breeds to various environmental conditions of Dagestan - from plains to mountains and foothills. This can also reveal the unique allelic characteristics of these genes, which is the central focus of our study. The DNA used for the study was extracted from the blood of Caucasian Brown cows bred in mountain (n=74) and foothill (n=52) vertical zonality, as well as the Red Steppe breed bred in the conditions of lowland Dagestan (n=52). The studied cattle populations were genotyped by the polymerase chain reaction method – restriction fragment length polymorphism (PCR-RFLP) on a programmable fourchannel thermal cycler "Tercik" of the company "DNA-technology" (Russia). The polymerase chain reaction (PCR) was carried out using synthesized specific primers. The study of the Caucasian brown cattle breed showed differences in the genetic profiles of individuals living in different ecosystems. In mountainous areas, the allele of the pituitary transcription factor PIT-1A occurs with a frequency of 0.10, while the allele PIT-1B - with a frequency of 0.90. On the contrary, in lowland areas, the proportion of the allele PIT-1A increases to 0.18, and PIT-1B decreases to 0.82. In the mountain zone, the genotypes PIT-1AA, PIT-1BB and PIT-1AB are 2.0%, 82.0% and 16.0%, respectively. In the plain zone, the genotype PIT-1AA is not observed. Cattle raised in certain natural conditions demonstrate unique allelic combinations that are the result of adaptation to the local environment. The data obtained allow us to take these features into account and use them in further breeding work.

Reindeer husbandry is the main branch of agriculture in the Arctic zone of the Russian Federation, and a form of traditional environmental management of the North peoples. To preserve and grow the industry, government support and the development of the principles of traditional management with the help of biotechnology are necessary. The article discusses the prospects for using reproductive technologies in fence keeping of reindeer. In reindeer breeding, none of the reproductive technologies are currently used, unlike other types of animal husbandry. The advantages of using assisted reproductive technologies in fenced reindeer herding are that reindeer herders obtain offspring of animals with favorable characteristics and manage reproduction. In addition, the development of technologies for working with sperm and embryos, the creation of cryopreserved biomaterial banks are important for the revival of endangered subspecies and intrabreed local genotypes. When keeping reindeer in a fenced area, it is possible to accustom animals to manipulations with an artificial vagina or electroejaculator. Free-range keeping of reindeer complicates the identification and fixation of individuals, observation and selection. With free-range keeping, uncontrolled mating may occur, it is impossibility of separating selected individuals, and creating harems. Fence keeping will allow to create necessary groups (recipients, synchronized females, females for artificial insemination, males for sperm extraction, etc.) and graze them separately, fix them, quickly find the necessary animals and carry out manipulations. Division into groups will also allow to carry out harem mating with selected males and females. Development and implementation of assisted reproductive technologies in northern reindeer herding will allow to intensify the selection process and improve the quality of reindeer products.

The work was carried out in the laboratory of cell engineering of the Federal State Budgetary Scientific Institution FRC VIZh named after L.K. Ernst, on the basis of Agrofirma Zarya LLC, Bogorodsky District, Nizhny Novgorod Region, in herds with a milk productivity of 8100 kg of milk per lactation, in the period 2017-2021. The reproductive abilities of 495 heifers were studied in the experiment. Depending on the semen procurement method, the calves were divided into two groups: Group I (n = 244) - calves obtained from semen harvested in the traditional way (TPS); Group II (n = 251) - calves that were obtained from inseminations with semen separated by sex (RSS). The health of the calves was observed during the lactation period, from birth to two months of age. Gastrointestinal tract (GIT) diseases and respiratory diseases (RDS) were taken into account. All data were statistically processed using Microsoft Office Excel software. Average values (M), errors (m), and variability (min-max) were studied. Reliability was calculated using the Student's t-test. It was found that during the observation period, 80.8% of calves were healthy, including 78.5% in Group II and 83.2% in Group I. The incidence of GIT diseases in Group I was 10.9%, RDS - 8.3%, and in Group II, these figures were 12.4% and 9.2%, respectively. Fertile insemination occurred in an average of 52.8% of heifers, including 56.7% in Group I and 48.7% in Group II. Abortions in group I were recorded in 5.1%, in group II – in 3.5% of animals.

The domestic Kalmyk cattle breed is considered unique and differs from all meat breeds bred in Russia. Animals of this breed are endowed with natural endurance and independence from climatic conditions, they are characterized by high adaptive ability, which makes it possible to breed them both in purity and in various schemes of crossing with other breeds in many regions and regions of our country. In addition, beef from animals of this breed has quite high quality and taste indicators. Given the increasing need for high-quality beef, the need for research aimed at increasing the meat productivity of cattle is an urgent task of agricultural science and practice.The aim of the work is to study the polymorphisms of the FASN and DGAT1 genes and their association with live weight in a population of Kalmyk bull calves bred in an extremely arid climatic and semi-arid ecological landscape zone of the Stavropol Territory. The studies were conducted in the conditions of SPK (kolkhozplemzavod) "Druzhba" (Druzhba collective farm) of Stavropol Krai on Kalmyk steers (n=156) at the age of 8 months. To study the polymorphisms of the FASN and DGAT1 genes, genotyping was performed by PCRPDRF using lyophilized ready-made GenPak ® PCR Core reaction mixtures using a pair of primers selected on the Primer-BLAST resource. It was found that animals carrying AG and GG genotypes in the replacement of g.17924A>G of the FASN gene had a live weight of 7.8 and 11.9% more than the AA genotype, as well as among the entire studied livestock for the two studied genes. Animals carrying the homozygous TT genotype of c.1416T > G polymorphism in the DGAT1 gene had a higher live weight among all animals studied for this gene by 5%.

Semen quality is the main parameter for evaluating sires. Sperm freezing is considered the main method for preserving animals with certain reproductive capabilities. The aim of the study was to investigate the quantitative and qualitative parameters of native and frozen-thawed semen in sires depending on the selection direction. The study was conducted at the base of JSC "GCV" in the Moscow Region, Podolsk, on 3 groups of bulls in the amount of 12 heads: Simmental bulls of the dairy direction (n=4) and meat direction (n=4) and Montbéliarde bulls of the dairy direction (n=4). A total of 477 samples were analyzed, including 173 samples from meat Simmentals (the number of samples in a group varied from 41 to 46); 160 samplings of dairy Simmentals (the number of samplings in a group varied from 32 to 46) and 144 samplings of Montbéliarde (the number of samplings in a group varied from 29 to 47). It was found that the defective ejaculates of native semen in beef bulls averaged 22.7%, the number of fertile spermatozoa 32.6%, while the percentage of defective ejaculates in dairy sires of the Simmental breed averaged 12%, the percentage of fertile spermatozoa at the level of 44.6%. Similar indicators were obtained in Montbéliarde bulls and amounted to 8.2% and 53.6%, respectively. Semen losses per bull were greatest in beef Simmentals (9,808 doses). In Montbéliardes, this figure was 3,795 doses. At a reliable level, the dose of frozen semen per 1 ejaculate in Simmental bulls of dairy orientation was 236 doses and in beef orientation - 201 doses (at P < 0.05). Individual characteristics were also established in bulls in all groups.

Currently, ART is developing rapidly in many animal species. The isolation of OCC from ovarian tissue makes it possible to obtain in vitro embryos for further culturing. Accordingly, culturing embryos in vitro, gives chances to obtain offspring in animals even after their death. Using the gametes of domestic cats as a model, it is possible to improve the technique of obtaining embryos, which can be applied to wild animals of the endangered feline family. The aim of our study was: using cat ovaries after routine ovariohysterectomy, to evaluate the criticality of the temperature regime and time interval during transportation of gonads to the laboratory prior to OCC isolation. The evaluation parameter was the percentage of oocytes at the MII stage, embryos at the morula and blastocyst stage. The method of obtaining OKCs, culturing oocytes and embryos was the same in all groups. The results show that the best values were achieved when the ovaries were received in the laboratory at a temperature of 25 °C and taken for 1 hour to 4 hours, while the increasing the time and decreasing the temperature negatively affects the competence to develop OCC. The study was carried out on the material obtained during scheduled ovariohysterectomy of 12 female cats orchidectomy of 5 male cats. As a result of the work, the technique of transportation of gonads to the laboratory was modified for felines, allowing to obtain a sufficient number of OCCs for subsequent culturing and fertilization in vitro. The technology of collecting feline oocytes and spermatozoa has been developed. The method of IVF and embryo culturing was improved. Based on the conducted research, an algorithm for obtaining quality feline embryos both for further embryotransfer and vitrification is developed.
Abbreviations: OCC - oocyte cumulus complex, IVF - in vitro fertilisation, ART - assisted reproductive technologies, OVHE - ovariohysterectomy.

The study was conducted to determine the possibility of using phenotypic correlations between traits as an indirect indicator of genetic correlations in domestic reindeer (Rangifer tarandus L.). The assessment of phenotypic parameters of the exterior and live weight of reindeer was carried out at the Yamal Experimental Station, a separate structural subdivision of the Federal State Budgetary Scientific Institution, the Tyumen Scientific Center, Siberian Branch of the Russian Academy of Sciences. The object of the study was a population sample of 94 adult females of the Nenets breed, selected at random, without constitution defects and having a calf. in October 2020. A total of 94 does (adult females) aged 3 to 9 years were examined. The animals were well-fed, had a calf and had no visible constitution defects. The sample showed high positive phenotypic correlations between “height at withers” and “height at elbow” (=0.84), “height at withers” and “chest depth” (=0.71), “live weight” and “chest girth” (=0.63), as well as between “live weight” and “chest depth” (=0.6). Genetic correlations between traits calculated using genotypes of microsatellite markers showed comparable results. For the pair of measurements “height at withers” and “height at elbow”, the genetic correlation was about 0.83, and for the pair “height at withers” and “chest depth” it was about 0.71. The results of comparative analysis between phenotypic and genetic correlation matrices demonstrated a high degree of consistency. It has been shown that phenotypic correlations can potentially be used as an indirect indicator of genetic correlations for reindeer selection for live weight and linear body dimensions.

Achieving satisfactory results of surgical treatment of cancer patients is impossible without pain control both intraoperatively and in the early postoperative period. The inclusion of regional anesthesia in multimodal pain control protocols can significantly improve the quality of analgesia and accelerate patient recovery after surgery. Nevertheless, each method of interfascial plane block has its own indications, contraindications, and complications. The purpose of our study was to show the validity and effectiveness of the use of regional anesthesia in the form of interfascial plane blocks during surgical resection of soft tissue tumors in the chest area in companion animals. The study were included 49 animals (30 dogs and 19 cats) who underwent surgery resection of soft tissue tumors in the chest area. The criterion for the inclusion of animals in the study was the use of regional anesthesia in the form of interfascial plane blocks in the anesthesia protocol. As a result of the study, it was revealed that the combination of several interfascial blocks provides a significantly better level of analgesia in resection of volumetric formations in the early postoperative period, however, when performing a unilateral mastectomy, the combination of a transversus abdominis plane block with a erector spinae plane block does not reduce the postoperative pain level. In mastectomies involving the cranial mammary glands, the best result for postoperative anesthesia is shown by the use of serratus anterior plane block. The inclusion of interfascial plane blocks in the anesthesia protocol for oncological patients makes it possible to significantly reduce or eliminate the use of narcotic analgesics in the perioperative period and, accordingly, avoid side effects and complications associated with the use of narcotic drugs, which is especially important for debilitated and geriatric patients.

The article presents a comparative characteristic of the radiological method and magnetic resonance tomography in the diagnosis of distal fractures. Method and magnetic resonance imaging method in diagnosing fractures of distal limbs in horses. The research was conducted on the basis of the veterinary clinic "Maxima Vet" and the department of diagnostics, internal noncommunicable diseases, pharmacology, surgery and obstetrics of FGBOU VO Omsk GAU from January 2023 to the present time. The object of the study were horses with suspected fracture of the metatarsal bone (n=9) and fracture of the proximal phalanx (n=11). A set of diagnostic methods was used, including primary examination, radiological examination and magnetic resonance imaging of the area with suspected pathology. Statistical processing of the obtained data was carried out according to generally accepted methods. Radiological examination of these types of fractures is not an objective method of diagnosis to a greater extent due to the planar nature of the image, which does not allow clear visualisation and differentiation of normal physiological structures from pathological ones, and there is a probability of their superimposition. Magnetic resonance imaging revealed fractures of the investigated areas in 100% of cases. It is worth noting that fractures of these structures were more frequently registered in males - geldings and stallions, while in mares these pathologies were much less frequent. The age of animals with sagittal fracture of the proximal phalanx was 10.4±0.9 years, with fracture of the lateral condyle of the third metatarsal bone - 9.8±0.7 years. The obtained results allow to improve differential diagnostics of pathologies of musculoskeletal apparatus in horses for immediate start of necessary therapy and quick recovery of the traumatised animal.

Background: spontaneous chronic corneal epithelial defects (SCCED) are common in dogs, they are characterized by superficial erosions and resistant to medications. Purpose: to compare effectiveness of superficial keratectomy and grid keratotomy alone and combinations of each of these techniques with diamond bur for SCCED. Materials and methods: the study included 63 dogs with this pathology, divided in groups: group 1 – treated by superficial keratectomy (n=15), group 2 – by grid keratotomy (n=14), group 3 – by combination of superficial keratectomy and diamond burr debidement (n=19), group 4 - with combination of grid keratotomy and diamond burr debidement (n=15). Results: 14 days after surgery, area of primary defect was completely epithelialized in group 1 - 93.3% of cases, in group 2 - 85.7%, group 3 - 100%, group 4 - 93.3%. New epithelial defects were present in group 1 in 60% of cases, group 2 – 50%, group 3 – 5.2%, group 4 – 6.7%. The time for complete healing of the cornea in group 1 was 19.9±5.3 days, group 2 – 19.4±6.5 days, group 3 – 14.8±3.7 days, in group 4 – 15.5 ±4.4 days. In groups 3 and 4, incidence of new corneal defects was statistically significantly less than in groups 1 and 2, and statistically significant decrease in healing time was found in groups 3 and 4 compared to groups 1 and 2. Conclusion: diamond burr debidement of the entire cornea in combination with superficial keratectomy or grid keratotomy is effective method for treating SCCED and it reduces healing time by an average of 4 days.

Mast cell tumors (MCTs) - is a malignant tumor consisting of mast cells (mastocytes). In English-language literature it is found under the terms "mast cell tumor", "mast cell sarcoma". It is highly common in dogs and is extremely important in the veterinary oncology field. Some breeds are predisposed to MCT development, including Boxer; Bull Terrier; French Bulldog; Golden Retriever; Labrador Retriever; Shar-pei; and Dachshund. On the other hand, some breeds present a lower risk of MCT development, including the German Shepherd, Chihuahua, Poodle, Yorkshire Terrier, and Cocker Spaniel. The metastatic potential of MCTs varies according to its histopathological classification, occurring in less than 10% of cases of well-differentiated mast cell tumors, in 5% to 22% of moderately differentiated neoplasms, and in 55% to 95% of poorly differentiated cases. In order to exclude tumor metastasis to internal organs, it is recommended to perform ultrasound of the abdominal cavity, computed tomography, with further determination of the metastasis site. In 8 out of 10 cases, we encountered a strong reaction to the suture material, regardless of its choice, as well as abundant exudation and alternation of various drainage systems. To wash the wound pocket and treat it, we used a 0.9% sodium chloride solution, or a combination of 0.9% sodium chloride solution and betadine in a ratio of 1:10. When using a 0.05% chlorhexidine solution, a decrease in the regenerative ability of the tissue and painful sensations during washing were eliminated. The further prognosis depends on the results of histological examination, the degree of malignancy, high/medium/low differentiated according to Patnaik and Kiupel. With highly differentiated mastocytoma, wide boundaries and clean edges of resection, the risk of metastasis is minimal and there is no need for chemotherapeutic treatment. However, it is always necessary to monitor the condition of the animal: a checkup by an oncologist, ultrasound of the liver and spleen monthly for the first 3 months, then gradually reduce the number of visits to 1 every 3 months three times, 1 every six months. Further recommendations for visits will depend on the oncologist' s discretion.

In the North-West region of Russia, the interest of athletes is concentrated mainly on classical types of equestrian sports (show jumping, dressage). Show jumping and dressage differ in many ways from endurance, but the main difference is the length of the distance (in endurance races the distance can reach 160 km), which requires training, first of all, for endurance. At the same time, in show jumping, as is known, horses overcome obstacles, and in dressage they perform elements in which the distribution of the load does not always occur evenly. Most likely, the nature and frequency of injuries in horses in endurance races over certain distances will differ from injuries in other types of equestrian sports. The results of these studies are relevant in connection with the widespread incidence of injuries in horses in equestrian sports in order to develop training schemes, preventive and therapeutic measures for injuries in horses participating in competitions in this area [4]. This equestrian sports area is quite young in the NorthWest region, relative to classical types, so there is a need for research. Previous studies have shown that the main cause of injuries in horses participating in races is overexertion caused by excessive accumulation of lactic acid in the muscles over long distances. While in classical equestrian sports the main etiological factors of injury are: excessive stretching of the tendons with a sharp contraction of the muscles, forcing training and, as a result, overheating of the tendons [2,3]. In general, it is known that the flexor tendons and the suspensory ligament (interosseous muscle) are most often injured in horses [1]. Analyzing the obtained research results, it was found that horses participating in equestrian distance endurance racing were more often diagnosed with injuries of the superficial digital flexor (SDF) and deep digital flexor (DDF) of the thoracic limbs, and horses used in classical equestrian sports, along with injuries of the SDF and DDF, were also diagnosed with injuries of the suspensory ligament (SDL) of both the thoracic and pelvic limbs.

The issues of anesthesia during surgical operations in farm animals require the improvement and application of modern methods of both general and local anesthesia. The method of epidural anesthesia and the choice of the optimal anesthetic for its implementation are becoming increasingly widespread in veterinary practice, its dosage determines the adequacy of anesthesia. The present study was conducted in order to conduct a comparative assessment of clinical efficacy when using modern local anesthetics for epidural anesthesia of sheep. A series of 60 tests were conducted on sheep using 2% lidocaine hydrochloride (group I), 2% lidocaine hydrochloride with adrenaline (group II) and 0,5% bupivacaine hydrochloride (group III) at the Department of General, Private and Operative Surgery of St. Petersburg State University of Veterinary Medicine in the period from January to July in 2024. Each of the groups consisted of 20 healthy sheep aged from 1 to 2 years. The effect of anesthetics on heart rate, respiration, respiratory volume, minute ventilation and rectal temperature was monitored. During epidural anesthesia with 0.5% bupivacaine solution, there was a significant decrease in heart rate, a slight decrease in respiration and a decrease in rectal temperature. The heart rate and respiration rate increased significantly when using 2% lidocaine and when using 2% lidocaine with adrenaline. The use of adrenaline in the second experimental group allowed to increase the duration of action of 2% lidocaine. The duration of anesthesia with 0,5% bupivacaine in the third group was the longest in comparison with other groups. Drowsiness, tympania and trembling were observed in some cases when using 0,5% bupivacaine. It follows from the present study that the use of 2% lidocaine is most reasonably in epidural anesthesia in sheep.

The publication presents anatomotopographical substantiation of mandibular anesthesia in the domestic cat. The research was carried out on the basis of the Department of Anatomy and Histology of Animals named after Prof. A.F. Klimov and Veterinary Surgery of the K.I. Skryabin Moscow State Automobile Academy of Veterinary Medicine and Biology. The object of the study was a domestic cat (Felis catus) (n=45) aged from 1 to 10 years. The material for the study were mandibles (n=15) and review radiographs of the head region (n=30). We used a complex methodical approach including: anatomical preparation for the purpose of skeletonization of the head, macromorphometry with determination of skeletotopic landmarks of the mandible, overview radiography of the bone structure of the head with subsequent decoding of the obtained information and radiogrammetry in the program “RadiAnt”, as well as statistical processing of the obtained digital data was carried out according to the generally accepted methods. In the analysis of mandibles and review radiographs, we have established species-specific and individual features of anatomo-topographic landmarks (mental and mandibular foramen) corresponding to the structural formations of the mandibular canal in the domestic cat. Thus the shape, variations and skeletotopia of the studied foramen are described. On the basis of the obtained results of macroscopic morphometry and radiogrammetry the skeletotopic landmarks of the mandibular canal-forming foramen are presented, which should be taken into account during mandibular anesthesia. The obtained results are basic for the development of new accesses to the mandibular branch of the trigeminal nerve when performing mandibular anesthesia in veterinary dentistry.

The paper presents the results of monitoring studies of orthopedic diseases conducted in 2023 at two modern high-tech enterprises with similar conditions for keeping replacement heifers: OOO «Kaluzhskaya Niva», RM «Koltsovo», and OOO «Okhotno», Bryansk Region. The prevalence and structure of orthopedic diseases in different age groups of heifers were studied, the etiological factors of diseases, reasons for culling were analyzed, and recommendations were given to reduce injuries to young cattle. In the surveyed enterprises, limb diseases in replacement heifers average 14.5%, while the analysis of the prevalence of orthopedic pathologies showed a similarity in the structure of lesions in both farms. Each age group of heifers is characterized by a certain list of limb diseases. The most common diseases of the extremities are bursitis and arthritis in the carpal and tarsal joints, which averaged 12.5% and 2.2%, respectively. The main etiological factor of extremity diseases in replacement heifers at the enterprise is trauma. Transportation of calves, their transfer to spacious group sections and the associated motor activity, slippery floors and protruding parts of ceilings lead to falls, blows and the appearance of wounds, abrasions, bruises, aseptic arthritis. Most orthopedic diseases have an inflammatory nature or are complicated by it. The percentage of culling of replacement heifers due to the economic inexpediency of treatment and unsuitability for transferring them to the main herd was 0.48% at the enterprise OOO «Kaluzhskaya Niva» and 0.6% at the enterprise OOO «Okhotno».