Recently, the assortment and sales volumes of fish products have increased significantly. In the market, fish products are in stable demand among consumers, in order to ensure the safety of these products, it is necessary to conduct a highquality veterinary and sanitary examination. The purpose of our study was to study and analyze "Veterinary rules for the appointment and conduct of veterinary and sanitary examination of fish, aquatic invertebrates and fish products made from them intended for processing and sale." To establish this goal, a study of the draft order on the approval of these veterinary regulations was conducted. To solve the tasks, we used the method of documentary analysis. Veterinary and sanitary examination of fish, aquatic invertebrates and fish products is carried out in order to establish the suitability of hydrobionts for use for food purposes. These products must comply with the safety requirements of the technical regulations of the Customs and Eurasian Economic Union, in particular "On food Safety" (TR CU 021/2011) and "On the safety of fish and fish products" (TR EAEU 040/2016). Also, one of the tasks is to establish the welfare of the farm in veterinary terms. According to the results of the research, a decision is made on the condition for the release of fish, aquatic invertebrates and fish products into circulation: this can be an implementation without restrictions, a direction for neutralization (by freezing or another method of neutralization, and can also be directed to cutting, cooking) or a direction for disposal.

The article presents an analysis of the current legislation in the field of biological waste management. Due to the presence of numerous regulatory and legal requirements for the handling of various wastes, difficulties arise in their implementation during the implementation of economic activities. Enterprises and organizations engaged in biological waste management activities should be guided not only by the requirements of legislation in the field of veterinary medicine, but also by environmental requirements. In this regard, there are objective difficulties in identifying all mandatory legal norms and, subsequently, compliance with them in economic activity. The result of contradictory and excessive requirements in the field of waste management are numerous fines [2] and court proceedings [3]. As recommendations, the article provides specific actions for economic entities that allow them to comply with the requirements of environmental legislation when carrying out activities for the disposal of biological waste by incineration.

The article presents the results of a comparative analysis of the requirements of regulatory documents of national standards of Russia, Belarus and Kazakhstan for the safety and quality of raw milk. We have conducted a comprehensive analysis of the requirements of TR CU 033/2013, GOST 31449-2013 and national products GOST R 52054-2003, ST RK 1760-2008, STB 1598-2006 in terms of requirements for the quality and safety of raw milk in these regulatory documents. Based on the documentary analysis of regulatory documents, the main indicators of the quality and safety of raw milk and the requirements for them in the states of the Eurasian Economic Union were identified and differences in the criteria for evaluating the varietal indicators of raw milk were identified.

Modern agriculture is a dynamically developing sector of the Russian economy, ready to actively introduce new technologies, carry out digital transformation of the Russian agro-industrial complex, and implement complex scientific and technical programs. An important task is to increase the attractiveness of agricultural professions. The system of training personnel, including veterinary specialists and workers in the field of veterinary medicine, should be flexible, capable of promptly responding to the requirements of the time and transforming to meet market demands. Agricultural universities are ready to change and introduce new specialties that will allow graduates to be in demand in the labor market. This explains the need for changes and revision of professional standards.
The article provides a comparative analysis of the qualification characteristics of the professional standard "Veterinarian" in 2018 and the professional standard "Veterinary (animal health) Worker" in 2021. The characteristics of the qualification levels of workers in the field of veterinary medicine, descriptions of generalized labor and labor functions in accordance with industry codes are given. The names of basic positions have been clarified in accordance with the requirements of classifiers and regulatory legal documents.

 This article shows the calculation of the effectiveness of the use of working time by veterinary specialists ichthyopathologists in fish farms of the  Novgorod region. The obtained calculations will help to scientifically  substantiate the rationing of work of veterinary specialists and ichthyopathologists.
The level of employment of veterinarians in operational work is average, ranging from 32.1 to 41.1%, which meets the requirements of state veterinary institutions. Preparatory and final work takes a lot of time, from 37.3 to 44.4%, due to the significant expenditure on the road to the cages. It should be noted that the analyzed farms have reserves for increasing the labor productivity of veterinary specialists in the amount of 11.25-18.22%,  including by eliminating the time spent on random unproductive work (from  10.7 to 15.8%). 

 The Federal Service for Veterinary and Phytosanitary Surveillance is a federal executive body. The functions of the Rosselkhoznadzor are defined by Decree of the Government of Russia of 30.06.2004 No. 327. The main areas of work are outlined in the Plan of Activities of the Federal Service for Veterinary and Phytosanitary Surveillance for 2021 and the Departmental Target Program «Organization of veterinary and Phytosanitary surveillance». It should be noted that the Program is being implemented in 2019-2025. The parameters of financial support for the implementation of the departmental target  program are decreasing. The full implementation of control and supervisory functions in the field of veterinary and phytosanitary surveillance is based on a risk-oriented approach.
After conducting a comparative analysis of the Passports of the departmental target program "Organization of Veterinary and Phytosanitary Surveillance"  approved on 1.06.2020 and 26.02.2021, National Reports on the progress  and results of the implementation in 2020 and 2019 of the State Program for the Development of Agriculture and Regulation of Markets of Agricultural Products, Raw Materials and approved by the Decree of the Government of  the Russian Federation of July 14, 2012 No. 717 "On the State Program for the Development of Agriculture and Regulation of Agricultural Products, Raw Materials and Food Markets" (subprogram "Organization of Veterinary and  Phytosanitary Surveillance"), it can be concluded that the scope of licensing  and control and supervisory functions in the field of veterinary and  phytosanitary supervision are based on a risk-based approach, this is the main goal of the Programs. At the same time, one can note a decrease in  financial support for the implementation of departmental target programs  and a slight adjustment of target indicators. 

Genital mycoplasmosis in cattle is characterized by a long course with mild symptoms, which can lead to irreversible changes in the reproductive organs. A study of the influence of genital mycoplasmosis in mothers cows on the vital properties of calves obtained from them was carried out. In calves from these cows, the dynamics of body weight gain and the incidence of diarrhea and bronchopneumonia were monitored for a month in relation to the group of animals obtained from healthy cows. It was found that calves born from cows with mycoplasmosis have significantly less body weight at birth, which is not restored during the first month of life, and the incidence of diarrhea is increased by 19.8% and bronchopneumonia by 15.1%.

This review article is devoted to the problems of the origin and spreading of antibiotic-resistant enterobacteria producing beta-lactamases in poultry farming.
The reason of the spreading of multidrug-resistant bacteria and diseases caused by them among farm animals and poultry is the irrational use of antibacterial agents, determination of enzymatic inactivation of antibiotics by laboratory methods, and the spread of resistance genes.
Most gram-negative bacteria such as Klebsiella spp., Escherichia coli, Proteus spp. and others, have tolerance to various antibiotics and disinfectants due to the production of beta-lactamase enzymes. Initially, some strains produced a wide range of beta-lactamases, and these isolates were susceptible to the 1st and 2nd generations of cephalosparins. Over time, the bacteria mutated, producing extended beta-lactamases. Such microorganisms are already resistant to the 3rd generation of cephalosparins. Antimicrobial resistance leads to limited therapeutic options, which increases the difficulty of treating diseased animals.
This problem is especially actual all over the world, many scientists conduct research to detect and study this phenomenon. The spread of antimicrobial resistance is one of the most acute problems of our time, carrying biological and economic threats to all countries. Many scientists are conducting research to detect and study the polyresistance of Enterobacteriaceae, such as E. coli and K. pneumoniae.
The modern infectious pathology of poultry is characterized by an increase in the frequency of occurrence and spreading of E. coli and K. pneumoniae, producing beta-lactamases, which contributes to ineffective antibiotic therapy.
The presence of multidrug-resistant opportunistic microorganisms isolated from poultry food can affect the health of consumers. The protection of the population from antibiotic resistance microorganisms should be based primarily on the protection of people from infection by any multidrug-resistant foodborne pathogens, therefore, it is necessary to improve diagnostic methods, therapeutic and prophylactic measures and the search for new highly effective drugs.

In order to improve treatment and prophylactic measures for bacterial etiology diseases of pigs the combined antibiotic Tildox was developed in the form of a powder. One gram of drag contains 100 mg of doxycycline hydrochloride and 100 mg of tylosin tartrate as active ingredients.
The aim of our research was to study the efficacy of Tildox in the treatment of enterococcal infection in piglets.
For the experiment 3 groups of 50 piglets of the rearing group were formed with a pre-established diagnosis of enterococcal infection. The study drug was administered orally at a dose of 1 g per 1 L of drinking water which corresponds to 100 mg of the drug (10 mg of doxycycline and 10 mg of tylosin) per 1 kg of animal body weight once a day. The animals of the first group were injected with the drug for 3 days, the animals of the second group were given the drug for 5 days. Animals of group 3 served as control - they were orally administered a third-party preparation based on doxycycline according to the instructions at a dose of 10 mg / kg of doxycycline once a day for 5 days. The diagnosis - enterococcal infection of piglets was confirmed by the method of bacteriological research. For this feces were collected from animals in the studied sectors. Diagnostics was carried out before the start of the experiment as well as immediately after the end of the experiment.
As a result of the research the following was established. The use of an antibiotic based on doxycycline and tylosin at a dose of 10 mg / kg for each active ingredient once a day for 5 days is the most effective way to treat piglets suffering from enterococcosis.

In the cattle farm, the effect of the use of the drug "Protostop" on the gut microbiota and the welfare of calves with diarrhea of bacterial origin was studied.
The drug "Protostop" was administered orally, in doses of 250 mg / kg or 350 mg / kg of weight for three or five days. Samples of feces were collected for bacteriological examination before the use of the drug and 10 days after the end of treatment. At  the same time, the animal welfare, their consumption of water and feed, the presence of changes in the functioning of the gastrointestinal tract, the nature of feces, the condition of mucous membranes and coat were evaluated. The content and species composition of the gut microbiota of calves before and 10 days after the use of the "Protostop" was established by bacteriological methods (inoculation on nutrient media with subsequent counting of grown colonies and identification of cultures).
After using the drug, independently of the dose and duration of use, significant improvements in the welfare of the animals were noted: calves became more active, diarrhea was stop, fecal masses became thicker and more homogeneous.
Changes in the content and species composition of Enterobacteria of the gut were most significant when using the “Protostop” at a dose of 350 mg / kg of weight for 5 days: 10 days after treatment, there were no strains of hemolytic E.coli and opportunistic microorganisms in the feces.
Based on the conducted studies, it was concluded that the drug "Protostop" is effective in the treatment of bacterial diarrhea in calves at a dose of 350 mg / kg of weight for 5 days.

The article provides information on the determination of the bacteriostatic and bactericidal activity of the disinfectants AQUAdes-NUK 5, Desinfexan and IncimaxxDES in relation to Salmonella typhimurium. The activity of disinfectants AQUAdes-NUK 5, Desinfexan and IncimaxxDES in the framework of determining their bactericidal activity and the severity of bacteriostatic properties was studied by the method of serial dilution, in which daily cultures of Salmonella typhimurium were used. During the research, the minimum concentrations were established at which bactericidal activity was manifested and a pronounced bacteriostatic effect was obtained. After processing the results obtained, we can conclude that the disinfectant AQUAdez-NUK 5 has a bacteriostatic effect on S. typhimurium at a concentration of 0.004%, but a pronounced bactericidal effect occurs only at a concentration of 0.008%. The degree of effect of IncimaxxDES disinfectant on S. typhimurium characterizes this agent as highly effective for disinfection when contaminated with this pathogenic microorganism. In particular, the bacteriostatic effect could be ascertained when the concentration reached 0.002%, the bactericidal effect at the 0.008% concentration, which indicates the high efficiency of the drug.Disinfexan has a pronounced antimicrobial effect, the bactericidal effect on S. typhimurium occurred at a similar dilution of 0.002%, and the bacteriostatic effect was manifested at lower dilutions of 0.0005%. In studies on the setting of control during bacteriological examination of the means AQUAdes-NUK 5, IncimaxxDES and Desinfexan, the growth of microorganisms was observed in test tubes into which the culture of S. typhimurium was enucleated. There was no growth in a test tube with the addition of distilled water to the BCH. The results obtained prove that the new disinfectant AQUAdes-NUK 5 exhibits pronounced bactericidal activity against the test microorganism S. typhimurium.

 Studies carried out and many literary data indicate that the ide, roach, rudd and bleak fish are infected with opisthorchid metacercariae much stronger  than the main commercial fish, such as bream, blue bream and silver carp.  Therefore, the latter are proposed to be assigned to the "potentially dangerous" group and allowed to be sold in fresh or cooled form, but only according to the results of a preliminary veterinary examination that confirmed their parasitic purity. This approach should be limited only to the European part of Russia, where the intensity of fish invasion by opisthorchid larvae is lower than in Western Siberia. 

The article reflects the main results of the study of veterinary and sanitary welfare of breeding products based on the use of molecular genetic, bacteriological methods. It has been established that genetic material is the subject of active international trade. The leader in the number of sperm doses imported into the territory of the Russian Federation in 2019 - 2020 is the United States.
The article provides an overview of modern measures aimed at minimizing the spread of bacteria, as well as fragmentarily presents the results of research work and the imperfection of the regulatory framework for the control of breeding products. At the same time, the direction in terms of regulatory and legal regulation is emphasized and justified, which corresponds to the priority goals of state policy both within the framework of the Food Security Doctrine of the Russian Federation, and in the field of ensuring biological safety to minimize biological risks associated with the introduction of rare or previously not found on the territory Of the Russian Federation of infectious diseases, spontaneous infection with infectious agents, entailing the emergence of obstetric-gynecological, andrological diseases and their spread during artificial insemination.
The article is devoted to the actual problem today, the purpose of which is to amend the provisions of regulatory legal acts to ensure the biological safety of breeding products.

Ketosis of highly productive cows is one of the most common metabolic pathologies, the etiological basis of which is the negative energy balance of the animal's body. The consequences of this disease is a deterioration in the health and productive qualities of the animal. Therefore, it is necessary to carry out timely and comprehensive diagnostics. The aim of these studies was to analyze the level of ketone bodies in the blood of highly productive Holstein cows and their clinical condition in the first three weeks of milk production. The studies were carried out in one of the livestock farms of the Leningrad region on 35 highly productive cows (the annual milk yield is more than 10,000 liters of milk) of the Holstein breed щт 5, 10, 15 and 20 days after calving. At the same time, the clinical manifestation of ketosis and concomitant diseases, as well as changes in the dynamics of the level of ketone bodies in the blood, were taken into account using test strips for the determination of ketone bodies in the Optium Xceed glucometer. According to the results of the studies, the average level of ketone bodies in the blood of cows on the 5th day after calving was 1.59 ± 1.08 mmol / l, which corresponded to the norm. In cows, on the 10-15th day after calving, an increase in the level of ketone bodies was noted by 1.3-1.4 times and averaged 2.1 ± 1.14 and 2.25 ± 1.4 mmol / l, respectively. On the 20th day after calving, the level of ketone bodies stabilized. It was equal to 1.55 ± 1.22 mmol / l. During the clinical examination of the animals, no obvious signs of ketosis were found. Throughout the experiment, 31% of the cows have had postpartum endometritis of first degree (according to the grades adopted at the farm: I, II, and III degrees), 2.8% - second degree, and 2.8% - third degree endometritis. Mastitis was registered in 22.7% of cows, and purulent pododermatitis in 2.8%. In addition, the animals with an increased level of ketone bodies were not recorded clinical manifestations of ketosis and concomitant diseases. And the cows with high level of ketone bodies in the blood was noted the presence of clinical signs of concomitant diseases (mastitis, endometrium, etc.). We can suggested the absence of a characteristic relationship between the content of ketone bodies in the animal's body and its health. It could be necessary to continue research on a larger livestock of animals and it should be pay an attention on the farm’s management, cows’ production schedule (milking, feeding, rest) and their productivity as well.

Despite the sufficient amount of antimicrobial drugs and specific therapy and prevention, the proportion of respiratory diseases in pigs is still quite high [2, 5, 6, 13]. In some farms, the incidence, as well as post-slaughter changes in the lungs, can reach up to 100%. At the same time, mortality is usually insignificant. The main damage among the pig population consists of an economic component - it is the culling of slaughter products, a decrease in weight gain, low conversion of feed, carrying out therapeutic and preventive measures. There is evidence of hypoxemia and hypoxia developing against this background, which can lead to the development of acidosis, a decrease in the barrier properties of organs and tissues and the development of organopathologies. The previously obtained data on immunological blood tests allow us to talk about the suppression of innate and adaptive immunity in nonspecific bronchopneumonia [2, 4, 5, 6, 12, 13].

The purpose of this work was to conduct biochemical studies to study the state of metabolic parameters of the blood of pigs of different age groups, patients with nonspecific bronchopneumonia.
The research was carried out at one of the large pig farms in the North-Western region of Russia and at the Department of Pathophysiology of the St. Petersburg State Medical University.
As a result of studies in all experimental groups of animals, the effect of nonspecific bronchopneumonia on biochemical processes in piglets was established. In all sick animals, a noticeable decrease in the content of total protein, albumins and globulins was found, which can lead to inhibition of the function of protective mechanisms, and from all links of immunity (innate and adaptive). At the same time, the activity of alkaline phosphatase and lactate dehydrogenase enzymes was established in sick piglets, which indicates the generalization of the process with liver damage and the development of acidosis.

The article presents the results of a screening study in ketosis in goats of the Saanen breed of industrial dairy content. As a result of the work, it was determined that up to 50% of the total livestock suffers from subclinical ketosis. Sick animals have protein metabolism disorders - hyperproteinemia without dysproteinemia, and pigment metabolism disorders - hyperbilirubinemia, the concentration of β-ketones in their blood increases to 0,9 mmol/l.

 The article discusses the main diagnostic methods used in the diagnosis of hypotrophic cardiomyopathy in cats. The work was carried out on the basis of one of the veterinary clinics in St. Petersburg. Of the clinical symptoms, the most common are shortness of breath, cyanosis, weakness, breathing through the mouth. Systemic hypertension was diagnosed in sick cats. In hypertrophic cardiomyopathy of cats, echocardiography is still the gold standard of diagnosis, but it is worth noting that for an accurate diagnosis, one should not be limited to ultrasound examination of the heart, a comprehensive assessment of the clinical status of the animal should be carried out and the degree of negative effect of HCM on a particular patient should be determined. 

The article presents the results of a study on the diagnosis and effectiveness of therapy methods for cows with ketosis. The aim is to evaluate the methods of diagnostics and treatment of highly productive cows with ketosis in the natural and technogenic province of the Middle Urals. Experimental studies were carried out on the territory of the Sverdlovsk region. Research material - feed samples, fresh cows, biological material from highly productive cows (blood, urine, milk). Sample preparation and study were carried out by methods generally accepted in zoo technical and veterinary practice.
The analysis revealed a concentrate type of feeding, an imbalance of the main nutrients (protein, sugar, fiber), a deficiency of essential trace elements (copper, cobalt, zinc, manganese), an excess of iron, the presence of heavy metals (nickel, lead, cadmium). All of these factors lead to the development of ketosis. On the farm, the disease is recorded in 13.6% of the number of calves. Ketosis manifests itself clinically (acetone odor of the skin and exhaled air, depression, immobility, decreased appetite to anorexia, cachexia, hypolactia and deterioration in milk quality, scar hypotension, hepatomegaly, liver tenderness, defecation disorder), hematologically (hypoproteinemia, hypoalbuminemia, hyperbiliminemia, hyperbiliminemia hypercreatininemia, hypoglycemia, hyperlactatemia, hyperketonemia and mineral imbalance), confirmed by the presence of ketone bodies in urine and milk.
The complex treatment of cows in the experimental group included a long diet, pathogenetic, substitution, detoxification and physiotherapy. The control group was not detoxified. The treatment was carried out for 20 days, and dietary and physiotherapy - 45 days. Significant changes have been achieved in the experimental group. On the 20th day, the level of trace elements in the blood of cows increased, and iron and toxic elements decreased in comparison with the background. The concentration of glucose increased, ketone bodies - decreased, not reaching the norm. The concentration of serum lactate, AST, bilirubin indicates incomplete recovery of the liver. The therapy carried out in the experimental groups has a positive effect, but does not lead to a complete recovery of the cows with ketosis.

Digestive system pathologies make up a significant part of cases of internal non-communicable diseases in dogs, and colitis is not the least of them. The disease occurs in dogs of all breeds and ages. Colitis is accompanied by a decrease or complete lack of appetite, diarrhea, dehydration, fever, and flatulence and soreness in the intestines. The aim of this study was to show the relevance of using different instrumental and laboratory methods for diagnosing colitis in dogs. The study was carried out on dogs of various breeds and ages, which were subjected to general methods of examination, radiological and endoscopic, followed by examination of biopsies obtained using targeted biopsy. X-ray diagnostics of the intestines in dogs with colitis revealed deformation of the folds of the intestinal mucosa, as well as disturbances in peristalsis. Colonoscopy revealed changes in the mucous membrane of the colon: hyperemia, edema, reduction or complete absence of folding, changes in the vascular pattern, mucus, petechiae, superficial ulcers. The histology of biopsy specimens of the colon mucous membrane of dogs with colitis made it possible to determine the severity of inflammatory processes in the colon and to confirm the pathology found during endoscopic examination for an accurate diagnosis. In the course of the work, it was shown that the most informative method for diagnosing colitis is endoscopic examination with targeted biopsy and subsequent histological examination of the samples obtained.

At present, the issue of the prevalence of fractures of the proximal phalanx among horses in the territory of the Russian Federation is insufficiently covered. This article analyzes statistical data on the incidence of this type of fracture, the information was collected based on the analysis of information from the database of the veterinary clinic "Maxima Vet". X-ray examination was used to diagnose and classify fractures. On the basis of its results, the method of treatment was determined. All horses (36 animals) described in the article underwent surgical treatment (osteosynthesis by screw fixation).
The results of the work indicate that there is a tendency for an annual increase in the number of visits to the clinic with fractures of the proximal phalanx, which may be associated with increased customer confidence, the spread of errors in keeping and training horses, an increase in the level of provision of animal owners, etc. In this case, the most common are short and long incomplete long pastern bone fractures (44.4% of all types), in which, however, animals have the most favorable prognosis.

 The article presents the results of studies on the use of the algorithm for examining a patient with inflammation of the middle ear. Timely diagnosis, determination of the localization of the affected areas and the appointment of medical and surgical treatment remains relevant. Prevention of preventing the progression of the disease of already existing symptoms is necessary to prevent the spread of inflammation to the unaffected structures of the ear. 

Modern Russian cattle breeding reflects the continuing trend of reducing the number of domestic unique aboriginal dairy breeds, and the remaining individual populations largely have the presence or absorption effect of the Holstein breed. The purpose of our research was to monitor the farms of the Arkhangelsk region for the preservation of the unique properties of the Kholmogorsky breed, where its genetic potential and the number of purebred livestock were historically concentrated. To achieve this goal, the following tasks were set: determination of the specific weight of the Kholmogorsky livestock in farms for various purposes (breeding plants, breeding farms, breeding producers); analysis of reproduction indicators of cows of the bull-producing group, the proportion of their bloodline and linear affiliation in crossing schemes. The main array of cattle surveyed by the farms of the region is represented by highly holstinized livestock (blood count above 75%), which reduces the period of economic use and productive longevity. A comparative analysis of the latter (productive longevity) showed that purebred Kholmogors were statistically not inferior to Holsteins.

One of the most pressing problems generated by the rapid development of technologies is the accumulation of various forms of plastic waste in the environment. The main criterion for observation was the systematic pollution of the coast with plastic waste. Considering the anthropogenic origin of materials that give rise to microplastics in water, optimal for humans and aquatic organisms, according to these recommendations, is its complete absence in the water of open water bodies, both marine and freshwater. The state monitoring program includes only stations in the deep part of the Neva Bay. Until now, the methods for the selection and determination of microplastics in water have not been standardized, and there are no uniform evaluation criteria. Summarizing the data for 2-3 years, it is difficult to talk about any patterns and trends in the distribution of microplastic particles.

In order to monitor the aquatic entomofauna, insects were captured in various sections of the watercourse, both located near beaver settlements and located on reservoirs where beaver settlements and traces of their stay were not found. The data obtained during the study indicate that near the settlements of the Eurasian beaver (Castor fiber), the number of species of aquatic Coleoptera, Hemiptera, and dragonflies encountered is higher than at other collection stations. No significant differences in the number of entomofauna species were found for other taxa.

High-quality and fast fish farming is very relevant and in demand nowadays. The african clary catfish is one of the representatives of aquatic organisms, which makes it possible to study complete embryogenesis in a short time in order to understand what favorable environmental conditions are necessary to obtain a larger volume of marketable fish. The aim of our study is to study the early stage of ontogenesis of Clarias gariepinus under the influence of changes in the degree of illumination of the environment. The material for the study was eggs obtained from females at the age of 2 years. The incubation was carried out on special mesh trays located on the surface of the pools. A total of 91000 eggs were laid for incubation. The eggs were fertilized by artificial insemination. The fertilized eggs were kept at an optimum temperature of 28,5°C. The first group was incubated in the dark, and the second under fluorescent lamps. Every 5-15 minutes, eggs were placed in a Petri dish and the material was counted and photographed using a digital camera.
The results of our research showed that 20 minutes after fertilization, the onset of blastodisc formation was recorded in both groups. After 35 minutes, cell cleavage begins. The duration of this period is considered from the moment of cleavage until the complete overgrowth of the embryonic disc with cells. After 80 minutes, further division of the embryonic cell occurs with the formation of a spherical structure - morula, as well as the overgrowth of the yolk with the embryonic layer. Later 15 hours, after fertilization, we found that the development of the embryo occurs evenly, with positive dynamics, regardless of illumination.
An analysis of the results obtained allows us to conclude that changes in light parameters do not have a negative effect on the rate of development of the Clarias gariepinus eggs.

Lake Velie is one of the largest reservoirs in the Novgorod region. It is part of the Valdai National Park and is located on the Valdai Moraine Ridge. However, environmental risks caused by pollution of the aquatic environment in areas where commercial aquaculture is grown, as well as the negative impact of fishery activities on the environment, can become an obstacle to further use of the lake water area for fishery purposes. Summarizing the data obtained, we can state the following: within a radius of 100 meters from the cages, the chemical composition of the water in the column is practically the same as in the central part of the lake.
The dispersion of the introduced substance obtained, both empirically and experimentally, corresponds to 50 m. At a distance of 50 m from the cages, water quality class 3 (moderately polluted). However, in a 10-meter zone, the water acquires the characteristic contaminated. In this part of the studied water area, the normative indicators for the content of biogenic substances on the surface and at the bottom are exceeded, and in the near -bottom horizon the numerical indicators are slightly higher than at the surface. This is most likely due to the accumulation of excessively introduced artificial feeds in the bottom horizon. Even with a favorable temperature and oxygen regime of the reservoir, such a situation does not contribute to the cultivation of healthy marketable fish. And the lack of comprehensive monitoring studies may leave unnoticed the prerequisites for the deterioration of water quality in Lake Velje.

Intensive use of radioactive isotopes in industry, abnormal emissions of nuclear fission products into the environment gradually increase the level of natural background radiation. As a result, there is a problem of farming, the main producer of food for the population, raw materials for industry, associated with the control of the level of contamination of soil, water, and livestock products. It is necessary to constantly monitor the radiation situation, namely the content of cesium-137 in soil, water, as well as in animal products both in the North-Western region and in other subjects of the Russian Federation. Due care must be taken when organizing the feeding of productive animals (dairy cows, beef cattle in the final fattening period), whose products, without an additional processing stage, can be directed to consumption by the population.

Honey is a product of processing by honey bees of nectar or paddy of vegetable or animal origin, which is a sweet aromatic substance or a crystallized mass containing a significant amount of carbohydrates, mineral and biologically active substances The article presents the results of veterinary and sanitary examination and evaluation of five samples of flower honey.
The purpose of the study: to determine the quality of honey obtained from apiaries of the Leningrad region in accordance with the "Rules of veterinary and sanitary examination of honey for sale in the markets."
The materials for the study were honey samples in the amount of 100 g with a collection date of 2020. For the study, the organoleptic and physico-chemical parameters of honey samples were determined. Organoleptic evaluation was carried out according to the following indicators: color, aroma, taste, consistency, crystallization, determination of signs of fermentation. Physico-chemical parameters: mass fraction of water, presence of oxymethylfurfural, diastase (amylase) activity, determination of total acidity.
As a result of organoleptic and physico-chemical studies, it turned out that in sample No. 1 there was an artificial inversion of honey and deviations were found, indicating that honey is not natural.

Against the background of a decrease in the consumption of fish products by the population, as well as a decrease in non -food products (fish meal, raw materials for animal husbandry, etc.), one of the primary tasks of agriculture is the development of small and large fish farming enterprises. In this regard, many farms are modifying cultivation technologies, moving to intensification of production and breeding of previously unused fish species. The hydrochemical study of the water was carried out on the basis of a fish farm specializing in the breeding of African clary catfish. As a result of the research, an excess of the concentration of ammonium and nitrate ions, an increase in the total hardness of water was revealed.

Modern farms are represented by different numbers of poultry, specialization and production volumes. In some cases, they are equipped with leading productive egg crosses. The aim of the research was to study the features of the reproduction of chickens in the conditions of farms specializing in the production of commercial eggs in the North-West region of the Russian Federation. The farm producing commercial chicken eggs in the Pskov region used the Loman Brown poultry, purchased from the Severo-Pskovskiy complex, as a parent flock. Since 2020, the farm has begun its own reproduction, using chickens and roosters purchased earlier and raised on the farm. The evaluation of the results of such use of the cross in a farm was carried out according to the indicators of safety, hatchability and early maturity of hatching, as well as the weight of the livestock obtained.
The selection for the increased weight of the hatching egg did not affect the weight of the received adult reproductive livestock and is at the lower border of the average value for the region. Indicators of hatching eggs in terms of hatchability, safety and early maturity of hatching deviated from the first generation of hatching by 5%. The hatchability was 80%; received chickens with developmental pathology - 1%. At hatching, in males and females, phenotypic differences were not revealed, which complicates the early and effective selection of females for the formation of a productive livestock on the farm.

It is shown that the distribution of species composition of malacofauna of the coastal zone is uneven. The species diversity of malacofauna of the coastal zone of the Novorossiysk Bay includes 17 species of mollusks: 11 species (65% of all species found) belong to the class Gastropoda, 5 species (29%) to the class Bivalvia, and 1 species (6%) to the class Polyplacophora. The basis of abundance throughout the studied coastal part is created by bivalve mollusks, predominantly of the genus Mytilaster, and gastropods of the genus Rissoa. The Black Sea is inhabited by representatives of 3 classes of mollusks: gastropods, bivalve mollusks and shell mollusks. Species composition of coastal mollusks by status consists of 3 groups: mass (5 species), common (4 species) and rare (8 species).

Soil quality is the most important environmental indicator that allows you to determine the suitability of soil for various uses, in particular, for targeted use in agriculture [1]. To minimize the risks associated with the threat to animal and human health, it is necessary to regularly conduct a comprehensive soil analysis. It includes a study on the content of a number of inorganic substances, primarily heavy metals, the presence of which in livestock and crop products is contrary to food safety criteria. With an increase in the rate of urbanization, agricultural land, on which the production of plant raw materials continues, falls within the boundaries of megalopolises [4]. Obviously, with the growth of anthropogenic load on these areas, agricultural work will have to be stopped here. An alternative could be the suburban areas as far away from pollution sources as possible. It is interesting to study the chemical composition of soils in St. Petersburg and the Leningrad region on plots that have already been used in agriculture and lands potentially suitable for this [5, 6]. In this study, the assessment of soil quality in two districts of the Leningrad region and in one district of St. Petersburg was carried out. The study was conducted between June and August 2021. The aim of the study was to assess the content of heavy metals in the soils of some districts of the Leningrad region and St. Petersburg.
Heavy metals were found in all samples taken, but their maximum permissible concentrations were exceeded only in St. Petersburg.

The pharynx is one of the first links in the respiratory and digestive systems. Knowledge of the peculiarities of the topography of the main highways of the pharynx, as well as their branches, is necessary for a veterinarian in the diagnosis, prevention and treatment of pathologies of the respiratory and digestive systems.
The aim of the study was to study the anatomical and topographic features of the pharyngeal blood supply in an AngloNubian goat. The studies were carried out on the basis of the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine. To study the blood supply to the pharynx, 15 corpses of Anglo-Nubian goats were examined and the following techniques were used: fine anatomical dissection, vaso-radiography and the manufacture of corrosive preparations.
According to the results of the study, it was found that of all parts of the pharynx, the highest intensity of vascularization in the Anglo-Nubian goat is observed in the oropharynx. The anatomical and topographic features of the arteries of different parts of the pharynx were established, it was determined that the arteries of different parts of the pharynx in their architectonics are diverse and variable both in terms of the type of branching and the breadth of the vascularization field and the degree of their tortuosity.

The article presents the results of a study of thyroid hormones - total triiodothyronine, total and free thyroxine in fresh cows at different ranges of bilirubin concentration in the blood. It was found that with an increase in the level of bilirubin, the functional activity of the thyroid gland decreases according to the principle of inverse relationship. It was found that the most sensitive marker to an increase in bilirubin is total T4. With a mild and moderate degree of hyperbilirubinemia, the level of this hormone decreases by 36.7-39.2%, with a pronounced increase in bilirubin in the blood, thyroxine decreases 3.6 times. With a slight increase in bilirubin in the blood, the level of T3 and fT4 decreases by 4.4-5.6%. With a more pronounced dysfunction of the liver, the degree of decrease in these hormones is much greater and is reliable. So, the concentration of T3 in groups decreases by 20.5-23.0%, and fT4 - by 33.4-40.0%. A decrease in the content of thyroid hormones in the blood against the background of hepatopathy is explained by a slowdown in all metabolic processes due to a decrease in the functional activity of the liver. The reason for the hypofunction of the thyroid gland is the lack of the need for the amount of hormones that is produced in the body of a healthy animal. Against the background of hepatopathy, the homeostasis of triiodothyronine, as the most important metabolically active thyroid hormone, is maximally maintained. At the same time, a decrease in the rate of catabolism of hormones in the liver does not contribute to a change in their concentration in the blood, since the half-life of T4 is much higher than T3, therefore it is the decrease in the rate of their synthesis in the gland and secretion into the blood that matters.

In this study, to activate the humoral link of nonspecific resistance of the fish organism, as well as to stimulate growth and development, prevent infectious and invasive diseases, the drug "SmartBiotic" was used, which contains humic acids. The research was carried out on the basis of LLC "Lososevo - whitefish nursery" Kingisepsky district, Leningrad region, the village of Velkota, which is the largest nursery in the city of Kingisepp for breeding rainbow trout. For the study, three groups of underyearlings of the rainbow trout (Oncorhynchus mykiss) were formed. One group served as control, and the other two were experimental. The first experimental group of young of the year received the drug at a concentration of 0.15%, and the second experimental group - at a dose of 0.25%. In the control group of rainbow trout, SmartBiotic was not used. All three groups were formed using the analog pairing method and raised in three different pools. Blood serum samples were taken twice: before giving postbiotic and one and a half months after using the drug. In the blood serum of fish in all three groups, the lysozyme activity of blood serum was determined according to the generally accepted method.

This article describes the results of a study of cholesterol metabolism in cows during the transit period. Cows were selected with optimal and increased body fatness during the dry period three weeks before calving. Blood samples were taken twice before calving and twice after calving at regular intervals. In the blood serum, the concentration of cholesterol and its fractions - low-density lipoprotein cholesterol and high-density lipoprotein - was studied, as well as the concentration of β-hydroxybutyric acid on the fifth day after calving. Studies have shown unidirectional dynamics of cholesterol and its fractions during the observation period. Initially, a decrease in all indicators was determined, the minimum values were found during the first week after calving. By the end of the experiment, all cholesterol fractions increased. It was found that in cows with increased body condition during the dry period, the level of LDL cholesterol in the post-calving period was significantly lower by 19.0-25.4% than in cows with optimal body condition. It was also found that in well-fed cows ketogenesis is more active 5 days after calving. Thus, in cows with increased and optimal fatness, the concentration of β- hydroxybutyric acid was 1.63 ± 0.18 and 1.23 ± 0.11 mmol / l, respectively, which may indicate the presence of subclinical ketosis in obese cows.

Diseases of the digestive organs in animals are quite common. They account for from 40.0 to 50.0 percent of all diseases with non-infectious pathology. Assessment of the possible consequences of the above-mentioned pathological processes, as well as the appointment of adequate treatment is extremely difficult without clear knowledge of the peculiarities of blood supply to internal organs. In connection with the above, the purpose of the study is to establish the features of the course and branching of the abdominal artery in a domestic cat. The material for the study was the corpses of ten cats aged eight to twelve years, excluding Maine Coon cats. The study was carried out using the method of vasorentgenography. The injection of the vascular bed was carried out through the abdominal aorta according to the generally accepted method. The injection mass was made according to the recipe: 1 part lead meerkat, 8 parts turpentine, 2 parts glycerin. After coagulation of the injection mass by performing a fine anatomical dissection, an organ complex was extracted from the corpse, including: the stomach with the final part of the esophagus and the initial part of the duodenum, pancreas and liver. X-ray shooting of the obtained preparations was carried out under the following technical conditions: current - 50 mA; tube voltage - 35 kV; focal length up to 50-60 cm; exposure - up to 1.5-3.0 seconds. Digital processing of the obtained images in order to determine morphometric parameters was carried out using the RadiAnt DICOM Viewer software. It was found that the abdominal artery in a domestic cat carries arterial blood to the stomach, liver and pancreas. On its way, it gives rise to the splenic, left gastric and common hepatic arteries, which, branching many times, form a number of intra-systemic anastomoses that form the pathways of collateral blood flow of the above organs.

This article presents an effect study of the biologically active water complex “HALPI” in dermatological conditions in canine red blood cell values. Biologically active water complex "HALPI" is produced according to the original recipe invented by the development Director of OOO "HALPI RUS", Vladimir Protasov. The prescription composition of the biologically active water complex "HALPI", in strict proportion includes components involved in the process of energy exchange in the cellular system of energy formation. The study was conducted on two groups of dogs with dermatological conditions (focal alopecia, erythema, pruritus): the experimental group was formed from dogs who were drinking biologically active water complex "HALPI" daily for 21 days and the control group, selected by the method of pairs of analogues. In the stabilized blood of both groups animals, such indicators as the number of red blood cells, hemoglobin level and hematocrit were determined. As a result of the analysis of the obtained data, it was revealed that the use of this biologically active water complex leads to normalization of the hydration status. Thus, the use of biologically active water complex "HALPI" can improve the state of metabolic processes by compensating for possible deficiencies of vitamins and trace elements, which contributes to improving the life quality of dogs with dermatological disorders.

To date, there has been a significant increase in industrial pork production in Russia. Improving the survival and safety of piggies of different age groups is the most important task of veterinary medicine. However, despite the sufficient amount of antimicrobial drugs and specific therapy and prevention, the proportion of pig diseases is still quite high [8, 10, 11]. At the same time, multiple literary sources [1, 2, 3] say that the situation with contamination of feed and food raw materials with mycotoxins in Russia and in most countries is unsatisfactory.
Hence, the aim of the work was to determine the presence of mycotoxins in the feed supplied to pig farms and to study the effect of even insignificant concentrations of mycotoxins in feed on the morphological parameters of the blood of pigs of different age groups: the level of erythrocytes, leukocytes, hemoglobin, the percentage of lymphocytes and monocytes, the rate of erythrocyte sedimentation.
The research was carried out at one of the large pig farms in the North-Western region of Russia and at the Department of Pathophysiology of the St. Petersburg State Medical University.
As a result of the studies, the following effect of toxic feeds on the morphological parameters of suckling piglets, piglets on rearing and fattening piglets was established: erythrocytopenia, hypochromemia, leukopenia, a decrease in the percentage of lymphocytes, monocytes.

The article discusses the results of hematological research in young cattle, which were obtained from mothers cows with hepatopathy. It was determined that most often in such calves, in comparison with calves obtained from clinically healthy cows, signs of anemia are observed, expressed in erythropenia and hypochromia of erythrocytes, a decrease in hematocrit to 0.281 ± 0.009 l / l, as well as signs of metabolic disorders - hypoproteinemia , decreased lipid concentration and hyperbilirubinemia.

The article deals with one of the most urgent problems of aquatic toxicology - the impact of heavy metals on the body of fish. The aim of the study was to analyze glucose indicators in carp after exposure to various concentrations of lead acetate, cadmium, zinc and copper. The experiment included 4 series of experiments, each of which was dedicated to a specific metal (lead, cadmium, zinc, copper). During the research, 1 control group (10 fish) was formed, and in each series of experiments, 3 experimental groups (10 fish) were formed. Experimental groups of fish were contained in a solution of heavy metal acetate with concentrations exceeding the MPC of heavy metals for fishery reservoirs by 10, 100 and 1000 times, respectively. The concentration of serum glucose was studied. An increase in glucose concentration due to heavy metal poisoning was found. However, exposure to 10 and 1000 MPC of zinc leads to a decrease in the concentration of glucose in the blood.

Currently, in veterinary morphology, special attention is paid to the study of the peripheral nervous system in companion animals in species and breed aspects. Dogs of the White Swiss Shepherd breed are especially valued in breeding for their conformation and watchdog qualities, and to this day they are a breed of dogs about whose anatomy there is not enough information. The purpose of our study is to study the anatomical and topographic features of the structure of the ulnar nerve in the White Swiss Shepherd Dog. The studies were carried out on the basis of the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine. The corpses of dogs of the White Swiss Shepherd breed aged from two to four years served as dated material. In total, ten corpses were examined, weighing 39.5 ± 1.0 kg. As a result of the study, it was found that in White Swiss Shepherd dogs, the ulnar nerve and its branches in the White Swiss Shepherd Dog participate in the innervation of the zeigo and autopodia, passing mainly along the medial surface of the forearm. Also, during the study, the morphometric indicators of the ulnar nerve and its branches were established.

In practice, veterinarians often encounter intestinal obstruction in small pets caused by ingestion of foreign objects. As a rule, it is accompanied by infringement of the obstructing body, which leads to a violation of the trophic part of the intestine and to its subsequent necrosis. Assessment of the possible consequences of this pathological process, as well as conducting competent surgical intervention to eliminate it, is extremely difficult without clear knowledge about the blood supply to the intestine. The purpose of the study is to establish the features of the course and branching of the cranial mesenteric artery in a domestic cat. The corpses of ten cats aged eight to twelve years, excluding Maine Coon cats, served as the material for its conduct. During the study, the method of vasorentgenography was used. The injection of the vascular bed was carried out through the abdominal aorta according to the generally accepted method. The injection mass was made according to the recipe: 1 part lead meerkat, 8 parts turpentine, 2 parts glycerin. After coagulation of the injection mass by performing a fine anatomical dissection, the intestines were removed from the corpse together with the mesentery supporting it. X-ray shooting of the obtained preparations was carried out under the following technical conditions: current - 50 mA; tube voltage - 35 kV; focal length up to 50-60 cm; exposure - up to 1.5-3.0 seconds. Digital processing of the obtained images in order to determine morphometric parameters was carried out using the RadiAnt DICOM Viewer software. It has been established that the cranial mesenteric artery in a domestic cat participates in the blood supply of the pancreas and most of the intestine, excluding the initial section of the duodenum, the distal part of the colon and the rectum. Branches extending from it richly anastomose with each other, forming many ways of collateral blood flow.

The results of a comparative histological study of the morphological reaction of parenchymal organs and organs of the immune system in broiler chickens using antibiotics and probiotics showed a positive effect of the probiotic drug on the body of broiler chickens of the experimental group. Two groups were formed according to the principle of analogues, a control and an experimental group of 35 heads each. Chickens of the control and experimental groups received the antibiotic enrofloxacin twice for 3 days up to 14 days of age according to the scheme of prevention of infectious diseases. Chickens of the experimental group received a feed additive (probiotic) based on microorganisms Bifidobacterium animalis from day 15 to 30. In a comparative study of the thymus of broiler chickens of the experimental group, the predominance of the cortical substance over the cerebral substance was noted in most of the lobules located on the periphery, and only in the merged lobules of the middle part of the thymus, the brain zone with a significant number of Ghassal bodies prevailed, a pseudoeosinophilic reaction was noted in the brain zone of the experimental chickens, as a result of the utilization of deposits and purification of the organ from the cells of the dead by the type of apoptosis.
Histological studies of the spleen revealed activation of lymphoid follicles: in the chickens of the control group they were single on the preparation, and in the chickens of the experimental group there were three or more of them in one field of view. This indicates the activation of humoral immunity in chickens of the experimental group.In the study of the pancreas in chickens of the experimental group, a positive tendency was noted to increase the number and size of the islets of Langerhans, which regulate the function of carbohydrate metabolism.
Analysis of the results of a comparative histological study of the morphological reaction of parenchymal organs and organs of the immune system showed that a number of reversible and irreversible pathological changes in organs were noted in the control group. Whereas in the experimental group where the probiotic was used, the organs corresponded to the physiological norm, which indicates a positive effect on the organs and on the body as a whole.

Based on published materials and archived data of the history of veterinary medicine in Mexico, there are presented the historical milestones of the development of veterinary medicine in the country and the prerequisites for the development of the veterinary school of Mexico, there are indicated the origin of state veterinary control. And also on a distinct example from the history of veterinary medicine, the role and importance of veterinary medicine in ensuring biological safety, in reducing and stopping emerging epizootics are shown. The problem of pressure of Mexico by other countries and other aspects of their relations in area of agriculture are indicated. The article shows the struggle of veterinary scientists with the political system of the country, their irrepressible craving for the development of discipline, which led to the formation of modern veterinary medicine in Mexico, as well as the path that the country has taken to ensure its biological well-being and food security.