Lumpy skin disease was first found in the Russian Federation in 2015. Since 2016, vaccination against lumpy skin disease has been mandatory for cattle of all age groups. In this regard, studying the effect of vaccination against lumpy skin disease on the reproductive ability of cows is relevant. One of the reasons for the decrease in the reproductive ability of cows is abortions at different stages of pregnancy. Statistical processing of abortions in Holstein cows for 2019-2022 was carried out. The first experimental group included animals, in which abortions were diagnosed in the period from the first to the sixth month after vaccination against lumpy skin disease; the second group – from the seventh to the twelfth month after vaccination. The total number of abortions during the reference period was 436. In the first experimental group, 232 abortions were diagnosed or 53.2% of all abortions, which was 6.4% more than in the second experimental group. A comparative assessment of the percentage of abortions at different stages of pregnancy indicated that in the first experimental group, abortions with a pregnancy period of less than 70 days accounted for 52.1%, which was 2.8% less than in the second experimental group, and abortions in late stages, correspondingly more by 2.8%. Thus, vaccination against lumpy skin disease may be one of the indirect causes of abortions in cows.

Bovine enzootic leukemia (EBLV) remains an acute problem for animal husbandry in many regions of Russia. Based on this, the goal was set: to study the epizootic situation of bovine leukemia in the Republic of Dagestan. The material for the study was taken from the official source of the Veterinary Committee of the Republic, as well as supplemented with our own serological blood tests for bovine leukemia virus (bovine leukemia). Laboratory tests for the detection of antibodies to BLV in RID were carried out according to the "Guidelines for the diagnosis of bovine leukemia" (2000). Research results: the spread of BLV has been established in some municipal districts and urban districts throughout the republic. In 2023, from all veterinary laboratories (stations), serological studies were conducted in the amount of 1101,689 animal blood samples for BLV. Of the animals studied, antibodies to the BLV antigen in RID were obtained in 2,778 (0.25%) samples. A high percentage of animal HCV infection was detected in the following districts and cities: Kizlyarsky – 2% (388), Tlaratinsky – 1.3% (341), Botlikhsky – 1.2% (450), Babayurt – 1.1% (188), Gunibsky – 0.8% (228) and in Makhachkala – 0.9% (180). In 16 districts and in Khasavyurt, the percentage of infection of animals with BLV was at the level of 0.3% or lower. We obtained 440 animal blood samples from sample farms, which were examined in the RID. 37 (8.4%) animal blood samples gave a positive result for BLV. Thus, the general epizootic situation in EBLV remains relevant, but the prevalence of BLV among animals is decreasing in the republic.

Addressing the problem of septic arthritis, caused by Staphylococcus aureus, is a matter of high importance for poultry industry nowadays. We conducted research into effectiveness of antimicrobials of different groups used for treating experimental infection in two-week old chicks. In the first experiment we determined the effectiveness of florfenicol, ofloxacin and a compound drug, containing ciprofloxacin and apramycin (100 mg/g and 500 mg/g). Florfenicol and ofloxacin were administered at concentrations 300 mg/L, 200 mg/L, 100 mg/L and 50 mg/L of drinking water, while the compound drug – 200 mg/L, 100 mg/L, 50 mg/L and 25 mg/L (considering ciprofloxacin). In the second experiment we studied the effectiveness of tilmicosin, administered via drinking water at concentrations 500 mg/L, 250 mg/L, 125 mg/L and 62.5 mg/L simultaneously with the challenge. For the challenge of the chicks, we used pathogenic culture of S. aureus. S. aureus in suspension was injected intraperitoneally at a dose 3 x 108 cells in 0.5 mL of 0.9% saline (2 MсFarland standard) per chick. The observation period was 20 days during which we watched the chicks and registered their morbidity rate and mortality rate. We came to a conclusion that florfenicol was most effective when the treatment of the chicks began 24 hours prior to the challenge; in the same situation the compound drug, containing ciprofloxacin and apramycin, was slightly less effective. Under these conditions the survivability of the infected chicks was 84% to 96%. When the treatment with ofloxacin via drinking water began 24 hours prior to the challenge of the chicks, it was no use as morbidity rate and mortality rate were similar or even higher compared to the control group, irrespective of the dose. When the treatment with tilmicosin via drinking water began simultaneously with the challenge of the chicks, it was rather effective at medium and low doses of 125 mg/L and 62.5 mg/L. However, the mortality rate of the chicks was high and the morbidity rate reached 56%.

The results of blood tests are important indicators for assessing and monitoring the health status, adaptation processes and metabolic states of the body. Currently, there is insufficient data on the effect of the Newcastle disease virus on peripheral blood parameters in animals, and there is also no information on changes in these parameters during Newcastle disease and the simultaneous use of silver preparations in animals. Although the mechanisms of the antiviral action of silver nanoparticles are not yet fully studied, researches show their effectiveness. The purpose of research was to study changes in hematological parameters with using silver preparations in laboratory ICR mice infected with Newcastle disease virus. The object of the study was the blood of laboratory ICR mice, infected with the Newcastle disease virus, and healthy ones as a control, and also silver preparations: Argosil and ArgovitMaxi. As a result of hematological studies, a significant effect of the Newcastle disease virus on hematological parameters was established. Deviations of the main blood parameters in infected animals were demonstrated: there was an increase in the content of granulocytes, the number of erythrocytes, the hemoglobin content and hematocrit; the number of lymphocytes and the average erythrocytes volume were reduced. It was also found that the use of the preparation Argosil significantly reduces the content of monocytes in ICR mice against the background of Newcastle disease viral infection. The use of the preparation Argovit significantly affects the decrease in monocytes and erythrocyte blood parameters: it increases the number of erythrocytes, hemoglobin, hematocrit, and reduces the average hemoglobin content in an erythrocyte, the average hemoglobin concentration in an erythrocyte.

The aim of the present study was to assess chemotherapeutic action of a levofloxacin-based drug, administered singly parenterally at doses 5 mg/kg and 10 mg/kg, for treatment of experimental colibacillosis of chicks. We conducted two experiments with day-old Hisex Brown chicks (body weight ranging from 39 g to 42 g). We challenged the chicks by injecting each of them with 0.5 mL of one-day old E. coli culture in suspension intraperitoneally, having adjusted its McFarland standard to ensure cell density of 1.5 х 10^8 CFUs (1 McFarland standard). For the first experiment we made 16 groups of chicks (n=10). The drug was injected intraperitoneally singly at doses 5 mg/kg and 10 mg/kg at 24h, 8h, 6h, 4h, 2h and 1h prior to the challenge and simultaneously with the challenge. In the second experiment we endeavoured to assess therapeutic effectiveness of levofloxacin and we made 20 groups of chicks (n=10). The drug was injected intraperitoneally singly at doses 5 mg/kg and 10 mg/kg at 0.5h, 1h, 2h, 3h, 4h, 5h, 6h and 7h following the challenge and simultaneously with the challenge. The experiments we conducted show that the total lifespan of the chicks was 92% when the drug was administered at a dose 5 mg/kg at 2h prior to the challenge. That dose 5 mg/kg therefore can be considered a highly active dose. When we increased the dose to 10 mg/kg the prophylactic effectiveness of the drug rose significantly. At all time intervals below 4 hours the dose of the drug was highly active.
When levofloxacin was administered for prophylaxis at a dose 5 mg/kg that dose was proven as highly active for all time intervals below 5 hours, and at a dose 10 mg/kg – 7 hours.

Currently, live attenuated vaccines are used in the Russian Federation for the specific prevention of classical swine fever (CSF), but this strategy contradicts the rules for importing animal products and carries the risks of recombination with field strains. These factors exacerbate the need for further development of candidate recombinant vaccines with similar efficacy and safety. The aim of the presented work was to construct a prokaryotic expression system of the marked glycoprotein E2 of the CSF virus and to evaluate its immunochemical properties. As a result of the conducted studies, a section of the primary amino acid sequence of glycoprotein E2 of a highly pathogenic Shimen strain (subgenotype 1.1) was identified using bioinformatic analysis and a hybrid polypeptide was designed, including a non-specific (marker) part from the modified V5 epitope and a fragment of the BSA sequence. By cloning a codon-optimized fragment into the pET-28a vector, the E. coli BL21(DE3) pLysS/pET-28a/E2-V5 producing strain was constructed. During the optimization of the cultivation conditions of the producer strain, it was found that the highest yield of the target protein is achieved within 5-6 hours after the induction of expression. The immunochemical properties of chromatographically purified recombinant rE2-V5 were determined: for example, it was shown that its activity in indirect enzyme immunoassay exceeds that of native E2. The data obtained indicate the effectiveness of the developed prokaryotic expression system, which consists in proper folding, good solubility and the ability of the target protein to form specific immunocomplexes. The presence of a marker fragment in the expressed hybrid polypeptide in the future will allow using the latter as the basis of a recombinant vaccine that meets the requirements of the DIVA strategy.

This article reflects current data on the assessment of the epizootic situation for the main endoparasitoses of small cattle in two peasant (farm) farms of the Luga district of the Leningrad region with similar animal conditions. The level of extensive invasion (EI) of sheep by pathogens of parasitic diseases was established, and the age and seasonal dynamics of the spread were studied. The level of infection of livestock with strongylates of the gastrointestinal tract with an EI of 87-97%, protostrongylidoses of the genus Mullerius (M. capillaris) with EI – 53%, tapeworms of the genus Moniezia (M. expansa) – 69%, trematodes Fasciola hepatica with EI – 24-28% and eimeria with EI – 96-98%. The analysis of the causes of diseases in the territories of the studied farms was carried out, and the main mechanisms of transmission of pathogens to susceptible animals were considered. A number of violations of the conditions of keeping small cattle in the conditions of the farms under study were identified: crowded livestock, untimely change of bedding and manure cleaning, keeping young animals together with adult animals, as well as violations of microclimate conditions (reduced air velocity and increased concentration of inert gases harmful to animals). In addition, an important factor in the spread of pathogens of invasive diseases among animals on the farms under study is the deworming of livestock without taking into account the characteristics of the life cycle of parasites and the timing of their preimaginal stages, as well as the duration of endogenous and exogenous stages of development of protozoa of the Eimeria genus.
Thus, causal relationships in the occurrence and circulation of pathogens of invasive diseases of small cattle among livestock in the territory of the farms of the Luga district of the Leningrad region were studied and determined, taking into account the climatic and geographical features of the area and the seasons of the year

Considering the high probability of the participation of stray dogs in the reservation and transmission of pathogens of infectious and invasive etiology, strict control is necessary not only over specific prevention, but also over the diagnosis of these diseases. Fleas are the most common ectoparasites in domestic animals. Flea parasitism in dogs is accompanied by anxiety, itching, and an allergic reaction. In addition, fleas are intermediate hosts of the causative agent of dipylidia. The purpose of the research was to study the spread of ctenocephalidosis among stray dogs in the city of Tyumen. The work was completed between 2016 and 2020. On the basis of the temporary detention center for stray pets of the Municipal government institution "LesParkKhoz" in Tyumen. A total of 4817 stray dogs were examined. For diagnosis, clinical, epizootological and parasitological research methods were used, the results obtained were processed using statistical methods. It was found that ctenocephalidosis occurred in 22.30% of stray dogs in the city of Tyumen. Most often, ctenocephalidosis was recorded among stray puppies under 1 year of age (36.03%) and in stray dogs aged 3 to 6 years (32.97%). Ctenocephalidosis was diagnosed throughout the year, the peak incidence was recorded in the autumn period in 46.28% of cases (of all cases of ctenocephalidosis for the specified period). Almost at the same level, flea infestation was recorded in spring and summer at 20.95% and 24.11%, respectively. Most often, stray dogs with ctenocephalidosis were admitted to the municipal shelter from the Central Administrative District (EI - 65.41% with AI 10.1 ± 0.5 individuals/animal). The causative agents of ctenocephalidosis in stray dogs in the city of Tyumen are C. felis and C. canis with a dominance index of 84.96% and 15.04%, respectively.

Fur farming is a branch of agriculture that specializes in breeding fur-bearing animals in order to obtain valuable fur skins from them. An important task of fur farming is to increase the quantity and quality of products obtained through intensification of production. This may lead to an increase in the number of outbreaks of infectious and invasive diseases. Ectoparasites negatively affect the quality of fur and can lead to the death of young animals. We conducted a study of the ectoparasite fauna in fur farms of the Tver region: «Savvatyevo» and «Mekha». We examined three types of furbearing animals: fox, American mink, and ferret. We performed a clinical examination of the animals; we examined the fur to detect fleas; we examined parasitological material from the auricle and external auditory canal under a microscope, we caught and determined the type of zoophilic flies. Ear mites O. cynotis have been reported in foxes and polecats. In foxes, infection rates: age 5 months – prevalence of infection 80,95%, intensity of infection 20,00 copies, at the age of 1 year – 86,67% and 6,67 copies, at the age of 2 years – 100,00% and 8,10 copies. For ferrets: age 3 months - no ear mites detected, age 1-year prevalence of infection 86,67%, intensity of infection 2,50 copies, age 2 years – 100,00% and 14,20 copies. Taking these data into account, all age groups of foxes support the invasive potential of O. cynotis equally, being a source of infection of new animals and a reservoir of the pathogen. Fleas C. (M.) s. sciurorum have been recorded in minks. The average prevalence of infection in adult males and females is 63,3%, the average intensity of infection is 11.6 specimens. The prevalence of infection of zoophilic flies was: M. domestica – 45,1%, L. caesar – 28,6%, P. regina – 11,9%, C. uralensis – 9,6%, F. canicularis – 4,8%. The number of flies in the shad was up to 30 individuals/m2. The data obtained indicate the wide distribution of arachnoenthomosis among fur-bearing animals in fur farms of the Tver region, which makes it urgent to introduce new schemes for the control and prevention of ectoparasites.

The domestic yak (Bos grunniens) is a two-humped hoofed mammal from the genus of true bulls. In 1973-1974, domestic yak was imported from the Alai Valley (Kyrgyzstan) and to the North Caucasus, in particular, to Kabardino-Balkaria, KarachayCherkessia, Dagestan, Chechnya, Ingushetia and North Ossetia-Alania. In Russia, yaks are found in animal husbandry in Tuva (more than 20 thousand heads), in Buryatia and Altai, in Karachay-Cherkessia (upper reaches of the Ullu-Ezen River) - more than 1.5 thousand heads, in Kabardino-Balkaria (Bezengi tract). 30 heads of animals were examined. All studies were performed by methods of complex helminthoscopy, in accordance with GOST R 54627-2011 "Agricultural ruminant animals. Methods of laboratory diagnosis of helminthiasis" Monitoring of the helminth fauna in yaks of the North Caucasian ecotype showed the presence of 24 species: trematodes - 3, cestodes - 5, nematodes - 16 species. Upon opening the internal organs of 30 individuals, 9 heads (30.0%) turned out to be infected with worms’ helminths, which is recorded with fluctuations in occurrence rates from 8.0 to 30.0% with a variation in abundance from 2.0 ± 0.3 to 547.0 ± 19.2 copies. per individual. The extent of echinococcal invasion in yaks of the North Caucasian ecotype was 10.0 % with an average invasion intensity of 13.6 ± 1.2 specimens. on the head. In the liver and lungs of yaks, all 66.2% of echinococcal cysts in the liquid sediment contained protoscolexes, and 33.8% of the cysts were acephalocysts without protoscolexes. Literature data confirm the without protoscolexes. Literature data confirm the simultaneous detection of a cystic form of echinococcosis of the liver and lungs caused by Echinococcus granulosus Batsch, 1789 (with protoscolexes and acephalocysts without protoscolexes) in yaks of the North Caucasian ecotype, which causes the likelihood of the formation of natural foci of echinococcosis in the highaltitude zone of the Caspian Sea with the participation of stray dogs and wild predators (wolf, jackal, etc.).

Most diseases affecting cows in the early stages of lactation are of an inflammatory nature and are associated with a decrease in reproductive function. Unfavorable environmental factors cause metabolic disorders, hormonal disorders and a decrease in the body's resistance. Favorable conditions are created for the development of opportunistic microflora in the reproductive organs of cows, causing inflammatory processes that can lead to infertility, decreased milk productivity and large economic losses. All this justifies the great interest shown in the study of obstetric and gynecological pathology by veterinary specialists, who consider the development and implementation of preventive and therapeutic measures to combat infertility as an urgent and serious task. Postpartum endometritis is a common disease in dairy herds. Antibiotics in treatment regimens become ineffective because pathogens infecting the uterine cavity develop resistance to them. Complex remedies are needed that have antiseptic, myotropic, wound healing and anti-inflammatory effects. A therapeutic veterinary drug «Endoseptam» has been developed, its high effectiveness in the prevention and treatment of endometritis has been proven. Studies are being conducted to establish the safety profile of the product. This article presents the results of studying the embryotoxic effect of the newly developed drug. White rats were used in the experiment. The drug was administered to laboratory animals per os at doses of 2000 mg/ kg and 20,000 mg / kg during 19 days of pregnancy. On the 20th day of pregnancy, some of the animals were euthanized and autopsied to assess the effects of «Endoseptam» on developing embryos/fetuses. The remaining part of the animals in the experiment was monitored to record the growth and development of offspring. The data obtained confirm the absence of toxic effects on developing embryos/fetuses of a complex remedy for the prevention and treatment of endometritis. When observing the physical development of offspring, there were no violations of embryonic development manifested in the postnatal period of life. The drug «Endoseptam» does not have an embryotoxic effect.

The parameters of acute toxicity of a chelate complex containing microelements: iron, manganese, copper, selenium, iodine was studied on outbred male rats. Toxic doses were determined by constructing a direct regression graph. Thus, groups of animals were formed that were administered an aqueous solution of the chelate complex in doses, ml/kg: 6.94; 8.89; 11.11 and 11.67. The response to the solution was assessed using generally accepted clinical and hematological methods. At the same time, the dynamics of temperature, live weight, mortality and peripheral blood parameters were taken into account. During the experiment, toxicity indicators were determined. The toxic effect in experimental animals manifested itself in the form of inhibition of activity, shortness of breath, decreased reactions to external stimuli, decreased body temperature, ruffled coat, and weight loss. In the blood, a significant increase in the number of leukocytes and erythrocytes was noted in rats receiving subsidies of the chelate microelement complex in doses of 8.89 ml/kg and 11.11 ml/kg. It was concluded that the introduction of a chelate complex of microelements led to stimulation of erythropoiesis and leukopoiesis, and according to the results of a study of toxicity indicators, the presented formulation corresponds to the 3rd hazard class. The parameters of acute toxicity of the chelate complex of microelements were determined, taking into account the survival of animals, LD50 was established - 907 ± 0.63 mg/kg; LD16 – 765 mg/kg; LD84 – 1076 mg/kg. It was concluded that the toxicity indicators of the chelate complex of microelements according to GOST 12.1.007–76 correspond to the 3rd hazard class - “moderately hazardous substances”. Considering the potential hematopoietic and antioxidant effect of trace elements in the chelate complex and the relatively low toxicity with other seleniumcontaining organic and inorganic additives and preparations, the use of this complex opens up opportunities and prospects for testing as a radioprotective agent.

Poultry meat is in great demand in the food market. The main method of producing poultry meat is raising broilers. The growth of broiler chickens is largely determined by balanced feeding. In recent years, poultry diets have increasingly included biologically active additives with a pronounced positive effect on the viability and productivity of poultry. In this regard, the purpose of our study was to study the effectiveness of the use of complex preventive measures for experimental combined T-2 and aflatoxicosis in broiler chickens, taking into account the clinical, hematological status and organ weight. Broiler chickens were divided into 4 groups: birds of the first group (biological control) received only complete feed that did not contain mycotoxins; the second group served as a toxic control (feed was contaminated with a mixture of mycotoxins); the third group received a basic diet contaminated with a mixture of mycotoxins with the addition of complex agent No. 1 (plant glucans, hepatoprotector, vitamins E and C, immunostimulant); the fourth group is the main diet, contaminated with a mixture of mycotoxins with the addition of complex agent No. 2 (natural mineral bentonite, succinic acid, immunostimulant, vitamin A, probiotic based on bifidobacteria and lactobacilli). The duration of administration of toxins and prophylactic agents is 21 days. Complex agents were administered at a dose of 0.25% of the diet. As a result of the use of these agents, a decrease in the toxic load on the body was noted, which was manifested by an improvement in the clinical condition of chickens and normalization of morphological blood parameters. These results suggest that the complexes can be an effective means for reducing the toxic effects of mycotoxins on the body of broiler chickens with combined mycotoxicoses.

Microscopic mold fungi are pathogens invisible to the naked eye that secrete dangerous metabolic products – mycotoxins. When exposed to various factors, mycotoxins can accumulate in plant and animal products. Getting into food and, as a result, into a living organism, they can lead to the appearance of mycoses and mycotoxicoses. The most common T-2 toxin of the Russian Federation territory. Due to the impossibility of completely eliminating microscopic fungi, the search for affordable preventive measures with detoxifying, immunostimulating properties remains relevant and promising. The aim of the study was to select adaptogens of various origins and evaluate their effectiveness in T-2 toxicosis of rats. The research was conducted on the basis of mycotoxin laboratory of the Federal state budgetary institution «Federal center for toxicological, radiation and biological safety» (Kazan). The tested adaptogens were echinacea purpurea grass, humic acids, biogenic stimulant ASD-2, zeolite from the Shatrashan deposit of the Republic of Tatarstan, and dry dead bee’s powder. In the course of work, the use of adaptogens such as echinacea purpurea, zeolite and dead bees turned out to be the most effective in relation to the survival of rats with T-2 toxicosis. The expected effect of a uniform increase in body weight of rats occurred, in turn, in groups of adaptogens with sorption capacity (humic acids, zeolite). The most striking positive picture during hematological examination was observed in groups using zeolite and dead bees. Based on the totality of the results obtained, it was concluded that zeolite and dead bees were the most effective in leveling the negative effects of T-2 toxicosis. The results obtained can become the basis for further development of a preventive complex.

The aim of the research was to determine the magnitude of the irritant effect on breast tissue and the morphobiochemical composition of blood in lactating cows with a single intracisternal administration of hyaluronidase. To do this, 1,280 units of hyaluronidase prepared in 10 ml of 0.9% sodium chloride solution were injected once into the posterior right quarter of the experimental group (n=10). The first heifers of the control group (n = 10) received a saline solution in its pure form. Before and after the administration of the drugs, the electrical conductivity and concentration of somatic cells in milk were determined (by the viscometric method), as well as the morphobiochemical composition of blood was studied. It was found that 12 hours after the introduction of the enzyme, the electrical conductivity of the secretion decreased by 7.6% (P ≤ 0.05), and after the first day it was completely restored to its initial values. The dynamics of the level of somatic cells 6 and 12 hours after the application of hyaluronidase in 40% of animals was characterized by values above 500 thousand / ml, and the average concentration of cells increased by 3 times. After the first and second days, the level of inflammatory reaction cells decreased by 2.0...2.5 times, relative to peak values. After 72 hours, the cell content in the secret decreased by 2.8 times in relation to the values obtained after 6 hours and by 27.7% in relation to the values established a day after the application of hyaluronidase, and did not significantly differ from the indicators before the introduction of the enzyme. The use of the drug did not significantly affect the morphobiochemical parameters of the blood of experimental animals. Thus, a single intracisternal administration of 1280 units of hyaluronidase to lactating cows is accompanied by a slight and short-term irritating effect on udder tissue, which allows further studies of this drug in the pharmacocorrection of breast pathologies.

The study of substance clearance plays an important role in the diagnosis of liver pathologies. Increased or decreased clearance of certain substances may indicate hepatobiliary disorders, including at the initial stages of the development of such pathologies, which allows us to evaluate the predictive potential of these assessment methods as high. The scientific literature provides detailed and statistically proven data on the use of substances such as galactose, amidopyrine, sorbitol and others in diagnostic protocols. Each substance is characterized by its own level of clearance, which allows one to obtain a comprehensive picture of the functioning of the hepatobiliary system. However, for most of the above exogenous substances, information in the scientific literature is either indicated in relation to humane medicine, or consists of pilot studies on a small number of animals, which requires additional testing of this kind to develop a statistically reliable array of data obtained. The purpose of this study is to conduct an experimental study aimed at studying changes in the pharmacokinetics of exogenous sorbitol in the blood plasma of laboratory animals with acute liver failure. The level of sorbitol was determined by the colorimetric Corcoran and Page method with modification (using potassium periodate and chromotropic acid, the method takes into account the calculated sorbitol indicator from the sum of polyols) using a UV-100 spectrophotometer (manufacturer – Shanghai Mapada Instruments Co., Ltd., China) for 12 hours (step – 2 hours) in blood plasma deproteinized using 0.4 M lithium perchlorate, obtained by venipuncture of the tail vein. Comparing pharmacokinetic curves with each other, it should be noted that in animals with acute liver failure, the graphical representation of sorbitol levels is similar to the inverse exponential, characterized by a sharp systematic decrease, while in clinically healthy animals the graphical representation of sorbitol levels is similar to the branch of a parabola, characterized by “smoothness” » reduction. The pharmacokinetic curves obtained in this study, which describe the levels of exogenous sorbitol in the blood plasma, can be used in the future as one of the methods for the early diagnosis of such pathologies.

Most diseases of young animals are initiated by pathologies of non-contagious etiology, such as disorders of degenerative processes, the imbalance of metabolism in the occurrence of which the leading role belongs to negative environmental factors. The purpose of our work was to study the state of the immune system and metabolism in calves during the period of changes in the type of feeding and the possibility of pharmacological correction of their disorders. An experiment was conducted on a dairy farm located in the Pscov’s region, the object of which was clinically healthy heifers. To conduct the experiment, using the method of selecting analogues, two groups of clinically healthy calves were formed at the age of 52 days: № 1 (control, n = 60) animals received feed in accordance with the technology, № 2 (n = 62) - in addition to basic diets, calves received three courses of 7 days with an interval of 5 days of sorption-metabolic premix at a dose of 0.20 g/kg per day. This feed additive has the properties of an enterosorbent, hepatoprotective and ruminoprotective agent, and its constituent flavonoids and humic acid affect the immune system. During the period of the experiment, i.e., from 53 to 86 days of life, calves undergo metabolic restructuring, which puts a functional load on all body systems with a corresponding risk of disruption of their functions. In particular, there is a risk of biochemical deficiency syndrome in the rumen, toxic liver dystrophy and anemia, the initiating factor of which, as our research has shown, is endogenous toxins, including proinflammatory interleukins. The administration of the phytopos-rum premix eliminated the accumulation of endotoxins and has a hepatoprotective effect, which reduces the risks of metabolic disorders, liver and bone marrow functions and digestive processes in the rumen, and increases the metabolic and immunological uniformity of the livestock.

The use of probiotics and symbiotics allows you to normalize the work of the gastrointestinal tract, normalize the microflora, increase immunity, prevent infectious diseases, and increase the safety of livestock. The aim of the research was to study the effect of complex application preparation "OptiBak®-F" in diets on the growth of young ferrets during the growing period. The experiment was carried out on slaughtered young ferrets of pearl type at the ferret farm FSUE "Russian Sable" of Moscow region. It was found that daily introduction of "OptiBak®-F" preparation into ferrets' feed in July-September in the amount of 0,05-0,06 g per head per day increases live weight gain of young animals in a month by 137,2 g (p<0,05) in comparison with animals of the control group. The similar tendency was maintained three weeks after completion of the preparation introduction into the general ration: at the end of September the live weight of young animals was significantly higher by 138.7 g (p<0.05) and was 2003.0 g against 1864.3 g in the control. High safety of young animals was recorded in both groups. Average daily feed intake in the groups was 225 g per head. During the experiment period when "OptiBak®-F" was used, absolute live weight gain of young ferrets in the experimental group was higher than in the control by 109.7 g (795.5 g vs. 685,8 g), relative - by 4.5% (49.6% vs. 45.1%), while feed costs in physical weight per unit of live weight gain decreased by 13.7%, and in terms of feed cost - by 11.0%, taking into account the cost of the preparation.

In 2023, more than 140 million units were produced in Russia. quail eggs, i.e., one egg per person per year. In this segment, the country is significantly inferior to many countries with developed poultry farming. But demand creates supply and in recent years the production of quail eggs has been intensively increasing, the share of which in the total balance of produced food eggs is 0.3% and is gradually growing. New breeds, crosses and lines of both egg and meat productivity are appearing. The purpose of the study was a comparative analysis of the morpho-biophysical qualities of eggs from the white Texas and Pharaoh meat breeds. However, there is practically very little information about the quality of eggs obtained from such breeds, despite the fact that the eggs are widely used both for incubation and in human nutrition. Therefore, the study of the morpho-biophysical qualities of quail eggs for meat production is not only relevant, but also of high practical importance. It was found that the weight of eggs of the Pharaoh breed was 8.5% higher compared to eggs of the white Texas breed, and the egg shape index was almost 3% lower. A comparison of the indicator characterizing the quality of protein in the studied breeds showed that the indicator of Hau units of Texas quail breed eggs was 88.74 and exceeded this indicator for Pharaoh eggs by 5.02%. In general, it should be said that the morpho-biophysical qualities of Texas white eggs were significantly different from those of the Pharaoh breed.

Existing methods for the determination of melamine in milk and its processed products are time-consuming to reproduce, require special equipment, training of personnel to work on this equipment, the use of chemical reagents and auxiliary equipment, often expensive. A separate area in the analysis of food products is spectroscopy in the middle infrared range, used to identify substances. The aim of the work was to record and analyze the infrared spectra of a standard sample of melamine in the middle spectral range using an NSAID prefix, a collapsible liquid cuvette and vaseline, as well as in tablets with KBr. The research was carried out in stages on the basis of the educational and research center for the examination of food and Animal Feed of the St. Petersburg State University of Veterinary Medicine in 2024. A standard sample of melamine was used as the research materials. At the first stage, the spectra of a standard sample of melamine were recorded using an infrared Fourier spectrometer "InfraLUM FT-08" and an NPVO prefix with a ZnSe crystal. At the next stage, the spectra of a standard sample of melamine in petroleum jelly were taken using a collapsible liquid cuvette, and then melamine pressed into tablets with KBr. As a result of the conducted studies, the presence of absorption bands of varying degrees of intensity in the IR spectra of the standard melamine sample was established, characterizing various types of fluctuations in the bonds of NH and CH groups. When comparing the IR spectra of melamine obtained at different stages of the study, a decrease in the intensity of the recorded absorption bands in different regions of the middle spectral range was revealed when using a liquid cuvette with vaseline and tablets with KBr. In addition, it was found that the IR spectrum of melamine obtained using the NSAID prefix exceeded the intensity of the absorption bands of similar spectra taken using KBr tablets and a liquid cuvette with vaseline.

Currently, by-products are used in the meat processing industry as raw materials for the production of various types of meat products, as well as sold in chilled and frozen form as a food product. When frozen, ice crystals form inside the cells, damaging the structural units of the cells, as a result of which, during defrosting, the turgor of the tissues is disrupted and the consistency of the offal changes. Such changes contribute to a decrease in the nutritional value of offal. In accordance with the current legislation of our country, raw meat subjected to defrosting should be sold as a product from frozen raw materials, and not as a chilled product. The aim of the work was to study the nutritional value of offal of slaughtered animals and poultry depending on the thermal condition. The study was carried out in the period 2023-2024 in the conditions of the educational and research center for the examination of food and animal feed of the St. Petersburg State University of Veterinary Medicine. The objects of the study were 112 samples of offal obtained from slaughtered animals and poultry. The quantitative content of protein, fat and moisture in the offal samples was determined using the infrared analyzer InfraLUM FT-12. As a result of the conducted studies, it was found that the greatest loss of nutritional value occurred in the offal of repeatedly defrosted compared with defrosted once. The loss of protein, fat and moisture in the offal of slaughtered animals and poultry did not occur in the same way and depended on the thermal condition and type of offal.

The development and intensification of the dairy industry currently often leads to the appearance of counterfeit food products in circulation. Component adulteration of milk is widespread in relation to the most valuable protein component. To date, the problem is that the estimation of the amount of protein in milk and its processed products by arbitration methods is based on the determination of nitrogen and is currently imperfect, since when adulterated with nitrogencontaining substances such as melamine, urea gives false inflated values and does not allow for operational input and production control. We have analyzed the regulatory framework, scientific publications of domestic and foreign authors, review materials from open sources over the past 10 years on the issues of falsification of the protein component of milk and its processed products, methods of identification of adulterating components. As a result of the analysis of regulatory documents and scientific literature, it was established that the existing methods approved in regulatory documents are laborious to reproduce, require special equipment, training of personnel to work on this equipment, the use of chemical reagents and auxiliary equipment, often expensive. The modern method of identifying melamine using infrared analyzers will allow to establish its quantitative values with great accuracy in the presence of appropriate calibration dependencies, in many ways accelerate and simplify the procedure for delivery and acceptance of raw milk while maintaining quality and safety indicators at a high level in accordance with regulatory documents.

Advances in applied chemistry have led to the emergence of a new group of organic toxicants - xenobiotics, which have found wide application in industry, agriculture and everyday life, and quickly spread through the biosphere, exerting a prolonged effect on living organisms, including humans. Research was carried out in the waters of the Shlisselburg, Volkhov and Svirskaya lips of the littoral zone of the southern part of Lake Ladoga in the period 2020-2023, using generally accepted methods of biological and chemical analytical analysis of fish and their habitat. 1500 specimens were examined. Fish and 3000 larvae. Chemical-analytical studies of samples of water, bottom sediments, atmospheric precipitation and fish for metals were carried out in the laboratory of fishery ecology of the St. Petersburg branch of the Federal State Budgetary Institution "VNIRO" ("GosNIORH" named after L.S. Berg) on an atomic absorption spectrophotometer AA - 7000 (Shimadzu) according to approved methods (PNDF., 2010; M02-2406., 2013 and M02-902-125, 2005), and in the research laboratory of food and natural objects "ANALECT" of the Institute of the Ministry of Health of the Russian Federation, using the method of atomic absorption spectrometry according to approved methods. Hydrochemical and hydrological indicators were determined using an automatic multiparameter probe Aqua TROLL 500. The content of metals in the fish habitat at the surveyed equators, as dangerous toxicants and previously significant for Lake Ladoga, showed their low content and especially such highly toxic ones as lead and cadmium. Minor excesses were noted for copper and manganese, but they could not in themselves be the cause of pathological manifestations of toxicosis in fish and disruption of the process of their natural reproduction.

To date, there is a large amount of information regarding the effect of heavy metals on the hydrolases of the digestive tract. It has been established that even biogenic metals in high concentrations can have a toxic effect. The assessment of the activity of digestive hydrolases is relevant, since a change in their activity has a direct effect on the effectiveness of assimilation of food. Amylolytic hydrolases help to provide the body with carbohydrates (along with fats) – the main sources of energy for fish. A decrease in the intake of carbohydrates will lead to a violation of metabolic processes and, as a result, underdevelopment and death of fish. The aim of the study was to determine the effect of an organomineral chelate complex on the amylolytic activity of intestinal enzymes of some fish species. The research was conducted at the Department of Biochemistry and Physiology of the St. Petersburg State University of Veterinary Medicine and on the basis of two fisheries in the Leningrad Region. The fish of the experimental groups (n = 10) were given an additive for 30 days, the data were compared with the control (n = 10). The drug was given together with the feed once a day, at a concentration of 0.5 g / kg (feed weight). Fingerlings (0+) of 3 species of freshwater bony fish were used as research objects: Carassius auratus (n=20), Cyprinus carpio (n=20), Oncorhynchus mykiss (n=20). Amylolytic activity was determined in the total homogenets of the intestinal mucosa of fish. The activity was assessed by the increase in hexoses by the Nelson method in the modification of Ugolev, Jesuitova. The detection was carried out on a photoelectric KKK-3 photometer. Based on the studies obtained, it can be concluded that the use of an organomineral chelate complex in the studied dosage (previously worked out in conditions of determining acute and chronic toxicity for fish) does not have a negative effect on the amylolytic activity of intestinal enzymes. There was no significant decrease in amylolytic activity in all experimental groups. Based on this, it is possible to recommend the use of a chelate complex for fish in industrial aquaculture.

Hyperkalemia, or elevated potassium levels in the blood, can have a serious effect on the body. High potassium levels can be both a cause and a consequence of impaired cell function, including cells of the heart, nervous system, muscles and other organs. The purpose of the presented study was to identify and evaluate the etiological causes leading to the development of hyperkalemia in cats in St. Petersburg with subsequent statistical processing of the results obtained. The serum levels of total protein, albumin, globulin, urea, creatinine, bilirubin, glucose, potassium, calcium, phosphorus, sodium, chlorine, as well as the activity of the enzymes alanine aminotransferase (AlAt), aspartate aminotransferase (AsAt) and alkaline phosphatase were determined. The study of biochemical parameters was carried out according to generally accepted methods. It was revealed that the most common causes of hyperkalemia in cats include disorders of the urinary system (52%) – acute renal failure, less often chronic kidney disease, as well as diseases of the gastrointestinal tract (24%), oncological processes (19%). It was also revealed that the survival rate for 7 days after diagnosis was approximately the same in groups with different levels of hyperkalemia and amounted to about 60-67%, which indicates the rapid reversibility of adverse reactions resulting from hyperkalemia with timely intervention. In the future, the study is planned to expand with the capture and analysis of individual nosological units and breed characteristics, as well as dietary characteristics, the ratio to the severity of the condition, the analysis of life expectancy and survival.

The biological effect of chromium on the body of farm animals is primarily due to the chemical form of the compound and the duration of use. Chromium is one of the most important ultramicroelements, but its essential role in the body was experimentally proven only in the second half of the 20^th century. The kinetic inertness of the ions of three-valence chromium does not allow the element to be involved in many biochemical reactions, at the same time, this effect ensures the prolongation of specific cellular processes associated with the entry of glucose into the cell. Among the most commonly used feed additives are: ultrafine or nanoparticles of trivalent chromium oxide, picolinate, acetate or propionate of chromium, complex compounds of amino acids with chromium. The issues of regulating their use depend on the specific country and the requirements for the maximum permissible concentrations of chromium content in feed and agricultural products obtained, as well as on the regulatory legislative framework. Numerous experimental data on the effects of chromium deficiency indicate the development of glucose tolerance, a decrease in the rate of its cellular utilization and a slowdown in energy metabolism. The effects observed when additional sources of chromium are introduced into the diet of cattle are expressed in increasing the digestibility of dry matter, acting on the activity of digestive enzymes, stimulating the species diversity of the rumen microbiota, increasing milk yield, etc. The experimental data obtained and the results of the meta-analysis confirm a significant increase in the productivity of dairy cows with the introduction of chromium supplements into the diet, which is an important achievement in the practice of dairy farming. Most of the work described in this review was carried out abroad, which requires intensification in Russia of both experimental research and work on correlation and regression analysis of the relationship between chromium supplements and productivity indicators of dairy cows.

The thymus is the main organ of the immune system, which is responsible for the formation and maintenance of immunogenesis, as well as the proliferation and differentiation of T-lymphocytes. In embryogenesis, the growth and development of the thymus occurs earlier than other peripheral organs of the immune system. Its laying in cattle is carried out in the early period of embryonic development (25-27 days), according to the periodization of life and critical phases of ontogenesis. By the time of birth, the thymus is fully formed and functional. Due to the successful development of immunology, information about the morphofunctional patterns of the organs of the immune system is significantly supplemented. However, despite significant advances in this field of morphology and physiology of immunocompetent organs, many questions, in particular about the structure of the thymus, remain insufficiently studied, especially in productive animals of different species and breeds. The study was conducted at the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine. The material was the corpses of the fruits of black-and-white calves in the amount of seven pieces at the age of 8-9 months of intrauterine development, with an average weight of 20.0 kg. Fine anatomical dissection, morphometry, weighing, and photographing were used as research methods. The aim of the study was to establish anatomical and topographic patterns of the thymus of black– and-white calves in prenatal ontogenesis, as well as to obtain morphometric data. As a result of the study, it was found that the thymus topographically begins from the thirteenth tracheal ring and goes to the third rib and consists of three lobes: cervical, middle, thoracic. The cervical lobe prevails over the middle and thoracic in all linear parameters, except for the width of the thoracic lobe. The intensity of growth of the cervical and thoracic lobes is asynchronous.

The nervous system is one of the leading integrating systems of the body. In combination with the cardiovascular and endocrine systems, it unites the body into a single whole. The nervous system controls the level of adaptive reactions of a living organism to changing environmental conditions. The white-bellied hedgehog (Atelerix albiventris) is a representative of the order of insectivorous animals. The purpose of our study is to study the macromorphology of individual anatomical structures of the brain of the white-bellied hedgehog (Atelerix albiventris). The material for the study was three heterosexual animals of the white-bellied hedgehog species (Atelerix albiventris) aged 1-4 years, obtained from private veterinary clinics. The methods used to study the brain of the white-bellied hedgehog included: fine anatomical dissection, morphometry, photography, and weighing. The work was carried out at the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine. The brain of the whitebellied hedgehog (Atelerix albiventris) (Figure 1, 2.) is arranged in accordance with the general plan of the structure of the mammalian brain, however, it is distinguished by the primitiveness of its development and is classified as lissencephalic in appearance. The average weight of cadaver material from females and males was 200.00±16.09 grams. There was no statistically significant difference between the body weight of females and males. It was also found that the caudal colliculi of the quadrigeminal are comparatively smaller than the cranial colliculi in both sexes, which allows us to conclude that the visual analyzer is relatively better developed in this species than the auditory one. The obtained materials can be used as reference material for continuing research on the brain of the white-bellied hedgehog (Atelerix albiventris), as well as in comparative morphology and physiology of humans and animals.

Atherosclerotic changes in the walls of arterial vessels are currently considered as one of the initial stages in the development of a number of diseases of the cardiovascular system. According to the World Health Organization, atherosclerosis is the main cause of heart attack and stroke. The similarity of pathomorphological changes in atherosclerosis in humans and in lower monkeys of the baboon hamadryad and baboon anubis species allows the use of animals of these species as laboratory models in the study of this disease. The material for morphological studies was obtained during the autopsy of 109 corpses of baboon hamadryad and baboon anubis monkeys (53 males and 56 females) in the period from 2019 to 2022. To analyze the species and age characteristics, all animals were conditionally divided into three age groups: group 1 (n=74) monkeys of both sexes aged 15-20 years; group 2 (n=23) animals of both sexes aged 21-25 years; group 3 (n=12) included animals older than 26 years. The results of the research showed that atherosclerotic changes in the aortic wall in the lower monkeys of the studied species kept in the nursery of the Kurchatov Complex of Medical Primatology of the Kurchatov Institute Research Center are detected from the age of 15. As the age of the animals increases, the changes are more pronounced. A reliable relationship between different age groups has been established. The frequency of atherosclerotic changes increases with increasing age, regardless of the sex of the animals. Morphological changes in the wall of the thoracic aorta in baboons are similar to those in human atherosclerosis.

Currently, the classical study of the anatomy of the skull bones in the form of fine anatomical preparation and morphometry are the standard in veterinary anatomy. The use of modern methods of visual diagnostics such as computed tomography significantly enriches the theoretical and practical material on the osteology of domestic and farm animals. Having studied the bibliographic data, we found a sufficient volume on the anatomy of the skull bones of goats of various breeds and ages. However, we did not establish the presence of data on the osteology of the skull of the Anglo-Nubian goat. In this regard, the purpose of our study is to study the anatomical, topographic and morphometric characteristics of the bones of the cranial skull of the Anglo-Nubian goat using classical anatomical methods and using computed tomography. The material for the study was the corpses of Anglo-Nubian goats (n = 20). The cadaver material was obtained farm located in the Moscow region. The age of the animals was 1-2 years. The study was conducted by morphometry and fine anatomical dissection, as well as visual diagnostics – computed tomography. Based on the results of the study, the anatomical and topographic characteristics of the bones of the cranial skull of the Anglo-Nubian goat were established and the morphometric characteristics of their structures were determined. The data obtained can be used for comparative anatomy with other farm animals, as well as in veterinary practice and experimental studies, where goats can be used as an anatomical model in the study of surgical approaches for performing surgical manipulations in the head area.

The study of the innervation of the main organ of the cardiovascular system, the heart, is an important problem of modern neurobiology. Most research on this topic is devoted to the study of nervous structures in humans and animals; glial cells are studied less. Nevertheless, glia plays an important role in maintaining the metabolism of the nervous apparatus and, by producing biologically active substances, affects the state of tissues and organs, both normally and in pathology. The purpose of this work is to study glial cells in the rat heart in the early postnatal period of development using an immunohistochemical marker, the S100β protein. The object of the study was the heart of Wistar rats at the age of seven days of postnatal development (P7) (n=12). Using immunohistochemical detection of a neural marker - the PGP 9.5 protein, the neural structures of the heart of P7 rats were studied. To identify glial cells, immunohistochemical detection of the S100β protein was used. The S100β protein belongs to the group of calcium-binding proteins and is expressed in glial cells of the central and peripheral nervous system. The study revealed a significant difference in the innervation of the upper and middle parts of the heart of P7 rats. Only in the right atrium was a pronounced concentration of nerve structures found, mainly in the region of the sinus node. It was established that in P7 rats, proepicardial cells express the S100β protein, characteristic of neurolemmocytes. A hypothesis has been put forward about the pos sibility of developing part of the glial cells of the myocardium of the right atrium and right ventricle from progenitor multipotent cells of the proepicardium through epithelialmesenchymal transformation.

In order to predict the timing of ovulation in mares, to obtain mature oocytes and follicular fluid in ART cycles, the domestic analogue of GnRH surfagon was used in two doses (40 and 50 mcg) against the background of comparison with the effectiveness of the previously used hCG drug. Surfagon injections were carried out intramuscularly when the leading follicle reached a diameter of 35 mm or more, and there was maximum or decreased edema of the uterus. An analysis of the duration of the intervals between intramuscular injection of 40 µg and 50 µg of the drug and ovulation showed that 72.4 and 35% of ovulations occur, respectively, between 37 and 48 hours after injection. The result of using 40 µg of surfagon is similar to the results of using hCG - 72 and 74% of ovulations in this period, respectively. Therefore, the drug “Surfagon” at a dose of 40 µg is most suitable for use in ART cycles. Only 3.4% of ovulations after the use of 40 µg of surfagon occur in the interval up to 24 hours after injection. Therefore, its use allows planning the collection of follicular fluid and oocyte from the preovulatory follicle using the OPU method after 24 hours. The domestic drug Surfagon (lyuleberin acetate, CJSC Mosagrogen, Moscow) is effective for the induction of ovulation in mares and can serve as an alternative to the use of HCG and imported GnRH analogues both in normal reproduction practice and in planning OPU procedures for the purpose of follicular fluid intake and oocyte extraction.

The purpose of this research was to study the influence of the conditioned medium of mesenchymal stem cells from adipose tissue and bone marrow of sheep on the quality parameters of sperm during a threehour incubation. The sperm of sexually mature rams of the Romanov and Dorper breeds at the age of 1-2.5 years was taken and examined. A total of 10 samples were taken (n=10). Conditioned medium (CM) was collected after 72 h of cultivation in mattresses with 90-100% cell monolayer. Three groups of samples, 10 in each, were formed: control (spermatozoa 7x1010 cells/ml + PBS buffer 100 μl, pH – 7.4), first experimental (spermatozoa 7x1010 cells/ml + conditioned medium (CM) MSC BM 2x108 cells/ml, pH – 7.2), the second experimental one (spermatozoa 7x1010 cells/ml + conditioned medium (CM) MSCs in adipose tissue 2x108 cells/ml, pH – 7.2). Comparisons of values were made at each incubation stage (0, 1, 2 and 3 hours) within each group. It was found that the use of conditioned medium of mesenchymal stem cells from adipose tissue and bone marrow of sheep at a concentration of 2x108 cells/ml and spermatozoa at a concentration of 7x1010 cells/ml in terms of improving the quality indicators of germ cells. During a three-hour incubation of sheep sperm with conditioned medium of mesenchymal stem cells (MS), a decrease in the number of progressively moving sperm was observed. At the same time, a statistically significant difference was recorded in the first experimental group (CS MSC BM) on the 3rd hour of incubation: 1.9 times (p<0.01), as well as in the second experimental group (CS MSC VT) on the 2nd and 3rd hour of incubation compared with indicators of 0 hour of incubation: 1.4 times (p≤0.05) and 2.4 (p<0.01), respectively. A statistically significant decrease in the number of morphologically normal sperm was recorded during an hour-long incubation with conditioned medium of MSCs from sheep bone marrow and amounted to 43.90±2.22% (p=0.04).

The biochemical composition of the mare’s follicle fluid was studied, and the level of identity of this composition with the biochemical parameters of their blood was established. It has been shown that the follicular fluid (FF) of large follicles (≥37 mm) contains significantly more electrolytes – Na, K, P and serum Fe, but significantly less total protein, uric acid, cholesterol, triglycerides, HDL cholesterol and intracellular enzymes - ALT, AST, CPK, LDH, GGTP, alkaline phosphatase, than in blood serum (p<0.05). At the same time, no significant differences were found in the content of glucose, urea, magnesium, albumin, all types of bilirubin, creatinine, LDL cholesterol, alphaamylase, and calcium in the studied media. The presence of correlations has been shown between the quantitative indicators of most components of the biochemical composition of the FF and blood serum, and in the FF itself - between the components of the lipid profile with Ca, P, glucose, and albumin. Significant relationships were also established between the content of serum Fe, Mg, Ca, total protein, urea, cholesterol, triglycerides, intracellular enzymes - ALT, AST, CPK, LDH, GGTP, alkaline phosphatase, bilirubin and creatinine in the FF and blood serum (p<0. 05). The obtained statistically reliable experimental data can be used for prognostic assessment of the composition of follicular fluid and the corresponding quality of oocytes based on biochemical analysis of blood serum in mares. The statistically reliable experimental data obtained can be used for a prognostic assessment of the composition of follicular fluid and the corresponding quality of oocytes by biochemical analysis of blood serum of mares.

The development and widespread practical application of in vitro embryo production technology will make it possible to replenish the herd population in a short time, preserve and replicate valuable genotypes, as well as create new genotypes using the method of genome editing. Livestock breeding is tasked with providing agriculture with a high–value herd in a fairly short time, while farmers are charged with replenishing the herd in a short time, which is possible only with the active introduction of assisted reproductive technologies, such as in vitro embryo production (IVP technology). The use of domestically produced cultural media in technology will ensure greater accessibility, reduced economic costs and the rapid development of breeding workin Russia. The purpose of the work was to evaluate the effectiveness of the IVP technology when using culture media from the domestic manufacturer SPE “PanEco” (Russia) to obtain cattle embryos in vitro. Our own protocol for obtaining cattle embryos was based on the protocols of culture media manufacturers SPE “PanEco” and IVF Bioscience (UK). Thus, for the first time using the line of media from the domestic manufacturer “PanEco” to obtain cattle embryos in vitro under incubation conditions at temperatures from plus 38.6 ◦C to plus 38.9 ◦C, CO2 content 6.2-6.8 % and uncontrolled humidity, on 6-8 days after a period of time from 140 to 182 hours from the moment of fertilization, 30.4 % of embryos were obtained at the blastocyst stage in relation to the total number of fertilized oocytes that reached the stage of 2 – 4 blastomeres.

A decrease in the reproductive ability of cows leads to losses in dairy farming, as dairy production decreases due to the lack of a lactation period in cows. Haplotype HH1 is responsible for a mutation in the protein apoptotic protease-activating factor 1 (APAF1), as a result of which its structure is shortened, resulting in a decrease in fertility, an increase in the number of embryonic mortality and abortions in Holstein dairy cattle. To study the polymorphism of the APAF1 gene (SNP p.Q579X [c.1741C>T]) and its associations with economically traits, we used data and DNA from 254 cows of Holstein population of indigenous selection of Breeding Farm Integrated Agricultural Production Center of the Republic of Tatarstan. As a result, 2 alleles (Q and X) and 2 genotypes (QQ and QX) were identified in the APAF1 – BstC8 I gene locus in cattle. It was established that the dominant population is represented by carriers of the homozygous QQ genotype of the APAF1 gene - 98.0 %, and the frequency of the Q allele reached 0.990. The percentage of QX-type animals is minimal - 2.0 % of the total number of cows subjected to the study, as a result of which the occurrence of the X allele was only 0.010. An assessment of the influence of APAF1 gene polymorphism on economically significant traits showed that, depending on the genotype, such reproduction traits as the age of the first fertile insemination, the duration of the dry period and the Doha fertility index vary statistically significantly. Analysis of dairy productivity traits that cows with the QQ genotype are significantly superior to individuals with the QX genotype in all compared positions, with the exception of the content of the mass fraction of fat. Through selection using genetic marking, damage to livestock farms can be reduced by reducing the frequency of carriers of lethal alleles in the parent generation. This research was supported by FASO Russia project, registration number 122011800138-7.

There are many publications revealing the physiological role of kisspeptin in the neurohumoral aspect in various species of wild and domestic animals. However, kisspeptin levels during puberty in cattle are still unclear. The purpose of the research was to study the concentrations of kisspeptin, progesterone and testosterone in the blood serum of Holstein bulls and heifers during puberty. Kisspeptin concentrations remained the same in bulls and heifers until the age of 4 months. Further, starting from 5 months, the concentration of kisspeptin increases in heifers, as does the concentration of progesterone. At the age of 9 and 10 months, the concentration of kisspeptin was significantly higher than in bulls. In bulls, testosterone concentration increased with age. Correlation analysis showed a significant relationship between the concentrations of kisspeptin and progesterone in heifers - a correlation coefficient of 0.797, P>0.01, and the concentrations of kisspeptin and testosterone in bulls - a correlation coefficient of 0.636, P>0.05. Kisspeptin most likely plays a role in puberty. Further research is needed on kisspeptin in relation to reproductive function in Bos Taurus.

Diagnosis of pregnancy is a responsible and integral procedure in the list of measures aimed at obtaining a healthy horse population. Pregnancy confirmation can be performed using different methods, with ultrasound examination (US) being the most widespread and universal. However, this method has some limitations and disadvantages.
An alternative to the ultrasound method for diagnosing pregnancy and monitoring the fetus in the middle and late stages of pregnancy can be the electrocardiography (ECG) method. A description of this method for recording the biopotentials of the fetal heart is found in Soviet and modern foreign literature. However, this method of research is not reflected in modern Russian literature and in practice has been undeservedly forgotten. The purpose of this study is to update data on the described diagnostic method, as well as to assess the possibility and reliability of using the ECG method for diagnosing and monitoring pregnancy in horses.
The experiment involved a Hanoverian mare whose pregnancy was confirmed by ultrasound. ECG registration was performed on days 121, 150, 184, 214, 245, 276, 304, 335 of pregnancy.
As a result of the research, the following was established. The earliest period of pregnancy at which it was possible to detect a fetal ECG was 150 days. By the 11th month of pregnancy, there was a clear trend towards a decrease in the fetal heart rate and a significant increase in the voltage of the fetal teeth.
This type of research is easily reproducible in the field, does not require expensive equipment, is characterized by a high level of objectivity of the data obtained and can be recommended for use in the daily practice of an equine veterinarian. As a research prospect, to identify general patterns and distinguish between states of conditional norm and pathology, it can be recommended to conduct further studies with a larger sample of animals.

Over the past decade, domestic pig farming has undergone significant changes in breeding and genetic work related to the breeding of highly productive breeding stock. Their reproductive ability and metabolic state of health depend on an adequate supply of macro- and microelements. Dynamic changes in mineral homeostasis are used as one of the diagnostic criteria for a full-fledged metabolic status. These indicators are homeoresistive for the animal body, and their dynamics can serve as constant in the development of methods for the diagnosis, prevention and prediction of animal diseases of various etiologies. The purpose of this study was to study the dynamics of sow mineral homeostasis during the breeding cycle, depending on the further course of the postpartum period. Studies of blood parameters were performed in the conditions of an industrial complex on the main sows. Blood was taken from the jugular vein during the reproductive cycle: background (before insemination), on the 30th and 80th day of pregnancy, after childbirth. After farrowing, the sows, according to the results of a clinical examination, were divided into two groups of 10 animals each: the remaining clinically healthy and those with postpartum diseases (endometritis, postpartum dysgalactia). As a result of a comparative analysis, identical dynamics of mineral indicators were established throughout the reproductive cycle in animals that remained healthy and became ill with postpartum diseases. In the blood serum of sows with postpartum pathology, there is a lower level of calcium, magnesium, iron, zinc, copper and an increased content of phosphorus. The greatest tension in mineral metabolism between diseased animals and the remaining healthy ones is observed after childbirth.

In recent years, genomic assessment and the widespread introduction of modern biotechnological techniques have played a leading role in the implementation of breeding programs. For a long time, increasing milk productivity has been the main goal of breeding. This led to a significant decrease in reproduction in herds. The reproductive indicators of the uterine livestock of cattle can largely reduce the total profitability due to additional costs for manual, veterinary assistance and forced culling. Experienced groups are genotyped using the Bovinesnp50 V3 Beadchip chip are formed from the cows of black-and-white holsteinized breed. For the study, the main reproductive traits of cows were chosen: the age of the first insemination, the insemination indices in front of the first (a), the second (b), the third (c), fourth (d) lactation and the period between hotels. Analysis of associations throughout the genome was carried out using EMMAX software. 2 significant SNP and 5 conditionally significant were found. The CAMK2D candidate gene with the age at the first insemination, the TLN2, WSCD2, GAPT genes with the indicator, the number of insemination and genes WDR36, TDRD10 with the inter -suffering period was identified. Based on the studies, we assume that with age there is a change in the genetic factors affecting animal fertility. The identified candidate genes affect the mechanisms of maturation of follicles, so the growth and development of embryos. The results can be used both for the selection of animals to improve reproduction indicators, and for the search for the fundamental foundations of the formation of fertility in cattle.

Feline uveitis is a common inflammatory disease of the vascular membrane of the eye. Damage to the uveal tract can be caused by a variety of causes, including systemic diseases, autoimmune processes, viral and bacterial infections, parasitic diseases, and oncological pathologies. Differential diagnosis of etiological factors is difficult and requires a comprehensive examination of the animal: careful collection of anamneses in order to exclude a traumatic factor, laboratory tests, serological tests to detect viral infections and parasitic infestations, visual diagnostic examination to diagnose systemic diseases and search for the oncological process. The research was conducted in 2023-2024 on the basis of the Department of Diseases of small domestic, laboratory and exotic animals, as well as the laboratory of "Oncology, Ophthalmology and Biochemistry of Animals" of the Federal State Budgetary Educational Institution "ROSBIOTECH". The aim of the study was to substantiate the use of sonographic and morphological research methods in the differential diagnosis of the etiology of feline uveitis. During the study, in 20.8% of cases (15 cats), sonographic examination of the abdominal cavity allowed to determine the cause of uveitis. We found: thickening of the muscular layer of the intestinal wall with partial or complete loss of layer differentiation, a local increase in the echogenicity of the surrounding adipose tissue, signs of mechanical obstruction of the proximally affected area, diffuse changes in mesenteric lymph nodes, diffuse focal changes in the liver and spleen, a volumetric neoplasm in the abdominal cavity located caudal to the right kidney, moderate nephromegaly and diffuse changes with violation of the differentiation of the cortical and cerebral layers. According to the results of morphological examination of the biopsy material, the diagnosis of large cell lymphoma was established in all cases. Uveitis in this group of cats is attributed to ophthalmopathy associated with paraneoplastic syndrome.

When performing osteosynthesis by screw fixation, it is important to carry out operational planning (choosing the screw of the optimal length and diameter). Choosing the optimal osteosynthesis tactics and the correct screw size allows you to stimulate regeneration and prevent possible complications. The X-ray examination method is included in the mandatory criterion of preoperative examination, which allows you to determine the size of the deformation and bone parameters. The present study is based on the hypothesis that the lifetime X-ray measurement of the bone of the proximal phalanx of a horse (longitudinal and transverse dimensions of the proximal and distal epiphysis and diaphysis, bone length), allows us to justify the size and technique of fixing the screw in the treatment of fractures. Morphometric studies included macroscopic dissection; morphometry of bone preparations; Xray measurement of the putus bone; documentation of the data obtained, photographing. A morphometric study was performed on 20 bone preparations (10 thoracic and 10 pelvic) and 40 X-ray images (20 in lateromedial and 20 in dorso-palmar/plantar projections) of the proximal phalanx of the horse. As a result of the work performed, it was found that the variability of parameters (longitudinal and transverse size of the proximal epiphysis, longitudinal and transverse size of the distal epiphysis; the longitudinal and transverse size of the diaphysis, bone length) of the fetal bone of the thoracic and pelvic limbs in horses for average values has no significant deviations (up to 1%), while the differences between the minimum and maximum values range from 20.0% to 66.6% for values obtained by anatomical method; from 12.2% and 33.3% for the Xray method.

Diseases of the distal extremities in dairy cows are a widespread pathology that leads to a significant decrease in animal productivity. They arise against the background of restrictions on the motor activity of animals, violation of diets, rules for the care of hooves and zoohygienic standards for maintenance. The structures of the distal extremities are combined into a functional complex of interconnected structures (joints, tendons, finger organ). With destructive changes in one of the structures, the rest also become involved in the pathological process, which leads to the chronization of the course of pathologies in this area. However, until now there has been no morphological confirmation of this concept. In this regard, the aim of the work is to study the macro– and microstructure of the organs of the distal extremities in dairy cows in conditions of intensive animal husbandry. Autosional material was studied (50 samples of the distal thoracic and pelvic extremities of dairy cows of the black-mottled Holstein breed). The methods of anatomical dissection and light microscopy were used. The research was conducted according to generally accepted methods. The micro-preparations were studied using Jenamed-2 and MicroScreen microscopes. Data on concomitant pathologies of the distal extremities in cattle were obtained: along with visually easily diagnosed disorders of the growth of the hoof horn and dermatitis, arthrosis of the finger joints was observed in all cases, especially pronounced in the hoof joints. Impaired horn growth is associated with dyskeratosis and parakeratosis. Joint damage is irreversible, due to the deep destruction of articular cartilage with its partial replacement by fibrous cartilage and connective tissue. There is reason to believe that the cause of such structural changes is hypokinesia and metabolic disorders in animals.

The study is relevant due to the high incidence of spinal cord compression pathologies in dogs requiring surgical intervention, and was carried out with the aim of conducting a biomechanical assessment of spinal cord decompression methods and identifying a decompression technique that has the least destabilizing effect on the thoracolumbar spine. The studies were carried out in 2023-2024. on the basis of the Department of Veterinary Surgery of the Moscow State Academy of Veterinary Medicine and Biotechnology - MBA named after K.I. Scriabin" and the Laboratory for the Development and Testing of Medical Devices and Materials of the Federal State Budgetary Institution "National Medical Research Center for Orthopedics named after. N.N. Priorov" of the Ministry of Health of the Russian Federation. The object of the study was sectional material, namely, samples of the thoracolumbar spine of dogs of chondrodystrophic and non-chondrodystrophic breeds weighing from 3 to 10 kg at the age of 5 to 8 years (20 samples in total). The range of motion of the vertebrae and the force of destruction of the spinal motion segments were determined in the native state and after modeling decompression techniques (hemilaminectomy and mini-hemilaminectomy). During hemilaminectomy, statistically significant changes in the biomechanical characteristics of the thoracolumbar spine were noted compared to mini-hemilaminectomy: an increase in the range of motion of the vertebrae in the area of decompression; increasing the range of motion of the vertebrae in topographically adjacent segments; reduction in the force of destruction of the segment in the area of decompression (changes are more pronounced in dogs of chondrodystrophic breeds). The data obtained by the authors of the article indicate that hemilaminectomy is a more destabilizing technique compared to minihemilaminectomy, and for extrusions in the thoracolumbar spine in dogs, preference should be given to mini-hemilaminectomy.

In modern conditions, the percentage of allergic diseases increases every year. A sufficient number of studies have been devoted to the study of various aspects of the pathology under consideration in small pets, but its solution will contribute to a comfortable life for the patient. According to the conducted research, it was found that among dermatological diseases, there were such as allergic: in cats 22.2%, in dogs 15.5%; parasitic in cats 13.3%, in dogs 10.5%; fungal in cats 6.3%, in dogs 7.2%, bacterial in cats 5.8%, in dogs 6.4%; thermal in cats 5.2%, in dogs 2.3%, chemical in cats 5.3%, in dogs 2.2%. Flea allergic dermatitis is a hypersensitivity reaction to one or more components of fleas, especially to allergens contained in their saliva. Flea dermatitis is most often recorded in late summer, which corresponds to the peak of flea numbers. The purpose of flea control is to eliminate them on pets, eliminate existing contamination in the environment and prevent re-infection. The main symptoms indicating allergic flea dermatitis: severe itching; numerous wounds due to scratching; hair falling out, the appearance of bald patches on the animal's body, ulcers covered with crusts; lack of appetite, vomiting; inappropriate behavior, irritability. When diagnosing allergic flea dermatitis, a number of factors were taken into account, including anamnesis, clinical signs, results of a wet test for the presence of fleas or their excrement, cytology of skin scraping, as well as the exclusion of other causes of dermatological diseases including atopic dermatitis and food allergies. The clinical signs of allergic flea dermatitis are variable and depend on the duration of the disease, as well as the degree of hypersensitivity and the consequences of previous or current treatment.

We studied some physical characteristics of the veterinary physiotherapeutic device UMI-V-05. The magnetic induction at different power levels was determined using TPU 02 militeslameter. The magnetic induction was measured for each power value. The probe of the milliteslameter was placed directly on the working surface, in the center of the inductor. It was found that the minimum magnetic induction of the device is 350±6.0 mTl, and the maximum is 1058±10.0 mTl. During the device operation, the heating of the inductor was determined using a thermal imager and a stopwatch. During the recommended time range (10 minutes), the inductor temperature did not exceed 46 °C. Determination of the pulse radiation frequency depending on the magnetic induction value was carried out using a stopwatch. At each working power the number of pulses per minute was counted and the number of pulses per second was calculated (frequency determination). It was revealed that UMI-V-05 is a low-frequency source of pulsed magnetic radiation with the maximum frequency of 1.3 Hz at the minimum magnetic induction of 350±6.0 mTl and the minimum frequency of 0.1 Hz at the maximum magnetic induction of 1058±10.0 mTl. Using a ruler and a TPU 02 milliteslameter, the degree of magnetic pulse attenuation depending on the distance to the working surface of UMI-V-05 was determined, it was fixed that the value of magnetic induction varies inversely proportional to the distance from the inductor. The penetration ability of the electromagnetic pulse through different media: biological and non-biological using TPU 02 militeslameter was studied. Biological tissues (muscle, bone) and some nonbiological media (paper, glass, wood, polyethylene, water) do not affect the passage of the electromagnetic pulse, while steel significantly reduces the passage of the pulse.