The results of research for 3 years (2019–2021) on winter rye (Secale cereale L.) crops in the North-West region of the Russian Federation (Leningrad region) are presented. The effect of different doses and timing of ammonium and potassium nitrate application on winter hardiness and productivity of winter rye plants on the example of Volkhova and Eureka varieties was studied. The soil in the experimental fields was sod-podzolic loamy with the depth of the arable horizon of 20–25 cm. Humus content – 2.0–2.3%, pH of the salt extract – 5.2–5.5. Fertilizers were applied in dry form in the autumn one week after the emergence of the seedlings, and in the spring – at the resumption of vegetation. The studied fertilizer doses in terms of active substance for nitrogen were 0 (control), 30, 60 and 90 kg/ha. It is shown that winter hardiness of both varieties practically did not depend on the doses and timing of the application, as well as on the type of fertilizers. The maximum grain yield was shown by the Volkhova variety at a dose of nitrogen of 60 kg/ha, the Eureka variety – 90 kg/ha, with the maximum yield of the Eureka variety for all the years exceeding that of the Volkhova variety by 24.5%. Within the specified doses of nitrogen for both varieties, the best option was a single spring application of a mixture of ammonium and potassium nitrate, the worst - a single spring application of ammonium nitrate alone. On average for both varieties, potassium nitrate application in spring increased the grain yield by 16% compared to the variants where potassium nitrate was not used.

The results of joint application of the biopreparation Sternifag, SP based on the fungus Trichoderma harzianum and urea ammonium nitrate (UAN-32) on spring wheat cultivated using the No-till technology in the northern forest-steppe of the Priobie region are presented. This zone is characterized by a short growing season and a mean annual moisture coefficient of 1.04–1.08. Under such conditions, No-till, or direct seeding, technology can minimize the cost of grain production. When growing crops according to this technology in the conditions of the northern forest-steppe, the sowing dates are postponed, which actualizes the use of biopreparation to accelerate the mineralization of straw residues. In production and stationary experiments on leached chernozem, the joint application of Sternifag and nitrogen fertilizer in autumn of the previous year activated decomposition of plant residues on second wheat by 33.0–49.0%. Application of the biopreparation together with UAN-32 allowed to obtain in the years of research additional 1 ha 1.5 and 0.96 tons of spring wheat grain (43.7–44.4%) due to an increase in the weight of 1000 grains, ear fineness and better preservation of plants for harvesting. Application of biopreparation Sternifag and UAN-32 on spring wheat grown on the basis of No-till technology in the northern forest-steppe of Priobie is economically beneficial. It is accompanied by an increase in profit by 2.0–2.4 times and an increase in the level of profitability of grain production by 27.0–36.0%. Effectiveness of cultivation of the crop on the background of liquid nitrogen fertilizer UAN-32 is lower. In this variant, grain productivity of spring wheat relative to the control increased in 2018, characterized by high humidity, by 1.1 t/ha, in 2020, characterized by June drought, by 0.74 t/ha. The level of profitability of grain production at application of UAN-32 is higher than in the control by 15.0–17.2%.

Results of the studies of photosynthetic activity of seedlings of three varieties of spring soft wheat grown under controlled climatic conditions and their response to infection with the pathogen of common root rot of cereals Bipolaris sorokiniana Shoem. by chlorophyll fluorescence (ChlF) parameters are presented. Chlorophyll fluorescence was recorded with a Dual-PAM-100/F fluorimeter in the mode of recording slow kinetics of dark induction curves with pulse saturation analysis (Slow Kinetics). The studies were conducted in 2021, 2022. The varietal specificity of formation of adaptive reactions of 10–16-day-old spring wheat seedlings under infection with B. sorokiniana (5000 conidia per grain) according to the daily dynamics of the ChlF parameters was established. The information content of the ChlF parameters Y(II), ETR, qP, Fv/Fm, Fv/F0, Y(NPQ), qN and Y(NО) as biomarkers for assessing pathogen resistance of the varieties at the level of photosynthetic apparatus was confirmed. The response of the more resistant wheat varieties Novosibirskaya 29 and Sibirskaya 21 to the pathogen introduction was less pronounced compared to the less resistant variety Novosibirskaya 41. The more resistant varieties exhibited the smallest changes in the ChlF parameters relative to the control. The greatest inter-variety differences in infection with B. sorokiniana (from 1.9 to 8.6 times) were manifested in 16-day-old seedlings. The level of the photosynthetic activity in the formation of adaptive reactions during the pathogenesis of B. sorokiniana can serve as a criterion of stress resistance, which will make it possible to conduct complex studies on modeling the system plant – host – pathogen, to assess the primary nonspecific reactions and adaptive components of stress resistance of spring wheat varieties.

The results of analysis of specific activity and multiple forms of oxidoreductase class enzymes are presented: antioxidant complex (catalase and peroxidase) and dehydrogenases (alcohol dehydrogenase, NAD⁺-malate dehydrogenase, glucose-6-phosphate dehydrogenase). Seven varieties of soybean (Glycine max (L.) Merrill) served as the object of the study. Dormant seeds and 3- and 7-day-old soybean seedlings were used for the analysis. Protein content was determined by the Lowry method, peroxidase activity was determined by colorimetric, catalase and the studied dehydrogenases – by spectrophotometric methods, electrophoretic spectra of enzymes – by electrophoresis on 7.5% polyacrylamide gel columns. Identification of the zones with enzymatic activity on the gel was performed by appropriate histochemical methods. Analysis of specific activity of antioxidant enzymes in dormant soybean seeds revealed increased activity of peroxidase and low activity of catalase. During seed germination, the inverse relationship of the specific activity of these enzymes is observed. On the 7th day the specific activity of catalase increases, that of peroxidase decreases to a minimum. In soybean germination, 5 forms of catalase were detected, indicating low polymorphism and stability of the enzyme, and 18 forms of peroxidase, which confirm high polymorphism and the possibility of using this enzyme as a marker of biochemical processes. Alcohol dehydrogenase and glucose-6-phosphate dehydrogenase were found to be of low heterogeneity, with the specific activity of these enzymes decreasing during germination compared to the dormant period of soybean seeds. The specific activity of NAD⁺-malate dehydrogenase increases slightly during germination. Eight forms of this enzyme were detected in the soybean varieties studied indicating increased polymorphism. In dormant soybean seeds, the electrophoretic spectra of NAD⁺-malate dehydrogenase exhibited varietal diversity allowing the enzyme to be used as a marker for further studies.

The article reflects the results of the study of mycotoxin contamination of silage harvested in 2021–2023 in the Vologda region. The main objective of the study was to assess the degree of mycotoxin contamination of different types of silage. The analyzed samples were represented by silages of different composition: legume-grass, cereal, corn, mixed grass and grass silage from natural lands. In total, more than 150 silage samples from 22 farms in the region were investigated. The content of mycotoxins (aflatoxin sum, ochratoxin A, zearalenone) in feeds was determined by enzyme immunoassay using standard test systems of ComProdService (Belarus). It has been established that almost all fodders harvested by farms in the Vologda region contain mycotoxins. Thus, more than 75% of samples contained aflatoxins at a concentration above 5 µg/kg (MAC), 45% contained ochratoxin A at a concentration also exceeding MAC. The most susceptible to aflatoxin contamination was legume-grass and corn silage, the proportion of contaminated samples in this case was 94 and 85%, respectively. The presence of ochratoxin A in high concentrations was more frequent in silage obtained from mixed grasses (91%). A high proportion of contaminated samples was also found in grass silage harvested from natural lands (73% aflatoxins, 48% ochratoxin A). The obtained results indicate the need for more careful control of silage preparation and storage at all stages of production, taking preventive measures by agricultural producers to reduce the negative consequences of the use of toxic fodder.

The results of growing new varieties of winter triticale in order to obtain herbage and grain are presented. The effectiveness of the use of triticale in fodder production, in particular, as part of complete mixed fodders when growing young fattening pigs on the materials of the Bryansk region and using it in a green forage chain when growing cattle is substantiated. The research was conducted in the Bryansk region in 2021, 2022. The superiority of triticale in terms of the main parameters in comparison with traditionally cultivated crops: rye and wheat has been proven. The combination of high yield and protein content allows increasing the yield per unit area of more valuable grain. The protein content in the grain of the rye variety Pukhovchanka was 12,4%, in the grain of the triticale variety Forte – 15,2%, and in the grain of the wheat variety Vladi – 14,1%, which indicates the highest protein content of triticale grain in comparison with the most common crops. The best results were obtained on the cultivation of the triticale variety Forte using mineral fertilizers in the amount of N₁₂₀P₁₃₀K₁₃₀, in which the grain yield averaged 91,4 centners per hectare over two years, the excess yield of wheat variety Vladi was 7,6 centners per hectare. The increase in the yield of triticale was due to the combination of rye with many ears and wheat with many flowers which ensured an increase in the mass of grain per ear. With a slight decrease in the density of the stem stand in the crops of triticale, its yield significantly exceeded other studied crops of the variety. When cultivating triticale for green fodder of the Elephant variety, the yield was 407,1 c/ha, which is 106,8 c/ha higher than the yield of the Pukhovchanka variety. The technological ripeness of triticale comes 7 days later than that of rye, so this crop fits well into the green forage chain. Due to high resistance to the most common and harmful diseases such as brown and stem rust, powdery mildew, green fodder triticale during the period of technological ripeness retains consumer qualities at a high level.

In recent years, there has been a significant deterioration of phytosanitary situation in plantings of many agricultural crops, including fodder crops. One of the valuable forage crops is soybean, which is becoming increasingly widespread outside its natural climatic zone. Under the conditions of Western Siberia, soybean crops are almost annually affected by a complex of diseases that significantly reduce the yield and quality of the seed material, which requires a comprehensive approach to ensure a minimum infectious background in crops. The development of epiphytotics on crops follows a certain dependence. The peak incidence of fungal infections is associated with increased temperature and humidity. Bacterial infections have a greater tolerance to low temperatures and may develop during the final phase of soybean vegetation. We investigated the correlation between the incidence rates of fungal and bacterial diseases of soybean and weather and climatic conditions of all the years of research. The research was conducted in 2016–2022 in the Novosibirsk region. The choice of the years of research is due to the formation of established populations of soybean phytopathogens that cause annual epiphytotics. SibNIIK 315 soybean variety was used as a sample for the study of the disease incidence in soybean crops. Based on long-term studies, this variety is the most affected of all the varieties. The leaf-stalk infections such as false mildew and pustular bacteriosis were considered as countable diseases. The use of correlation analysis to establish the degree of interrelation between the main indicators of soybean crop infestation and weather and climatic conditions of the growing season allowed to reveal a certain relationship – mainly due to the fact that fungal infections in all the years of research were manifested by the type of the epiphytotics. However, this method is not well suited for low prevalence diseases and diseases with short-term outbreaks.

Functioning of the granulosa cells of animal ovarian follicles (OF) determines the growth and development of the OF and the oocyte formed in it, which determines their use in modeling the composition of media for oocyte maturation in vitro in cell reproductive technologies. The purpose of the study is to determine the peculiarities of functional activity of granulosa cells in follicles of different diameters (< 3, 3–5, 5–8 mm) using complex testing of granulosa cell viability parameters (apoptosis level, production of reactive oxygen species, functional activity of mitochondria and lipidome) and hormonal status of follicle fluid (estradiol, testosterone, anti-Müllerian hormone level) in order to optimize the composition of the culture media for in vitro maturation of pig oocytes. The experiments found that the proportion of apoptotic cells in the OF increased as the diameter of the OF increased (by 11% in OFs 5–8 mm in diameter, by 4% in OFs < 3 mm in diameter). There was an increase in the number of high reactive oxygen species cells (by 10% in 5–8 mm diameter OF compared with < 3 mm diameter OF) and high mitochondrial activity (by 12% in 5–8 mm diameter OF compared with < 3 mm diameter OF). Correlations were found between the group of cells with high generation of reactive oxygen species and the level of apoptosis (0.500, p < 0.05), as well as with high levels of mitochondrial activity (0.500, p < 0.05). Estradiol concentration in follicular fluid increased as the OF grew (1.50 ng/ml in OF < 3 mm diameter and 2.09 ng/ml in OF 3–5 mm diameter, p < 0.01), being almost unchanged in OF 5–8 mm diameter (2.11 ng/ml), as was the testosterone concentration. Correlations were found between the proportion of the cells with high NileRed/LD FI (a marker of lipid droplet functional activity) and the levels of estradiol (0.998, p < 0.05), testosterone (0.500, p < 0.05), and anti-Müllerian hormone (–0.500, p < 0.05) in the dynamics of folliculogenesis, as well as between estradiol concentration and the proportion of cells with high mitochondrial activity (0.746, p < 0.05). Correlations were detected between the concentrations of estradiol and anti-Müllerian hormone, testosterone and anti-Müllerian hormone (–1.000, p < 0.05), between the level of apoptotic cells and the concentration of anti-Müllerian hormone in follicular fluid (–1.000, p < 0.05). The results of the monitoring of the viability and functional activity of porcine OF granulosa cells supplement the available data on the peculiarities of their functioning in the dynamics of folliculogenesis and can be used in modeling the systems of in vitro maturation of donor oocytes of Sus Scrofa Domesticus.

Residual antimicrobial substances resulting from the overuse of growth-promoting antibiotics in animal feed pose an emerging threat to human health and the environment. Plant extracts containing essential oils in general, and in particular Origanum vulgare extract, are a potential alternative to feed antibiotics, contributing to the growth of productive potential, due to their antimicrobial and antioxidant properties. They can inhibit the reproduction of pathogenic microorganisms, causing conformational changes in cell membranes. In this regard, the purpose of the study was to study the effect of different dosages of O. vulgare extract on the digestibility of diet components and the composition of volatile fatty acids in the rumen content under in vitro conditions. Three dosages of the oregano extract were tested in the experiment: 0.5; 1; 10 ml/l. The results of the present study indicate that small doses of O. vulgare extract do not lead to metabolic shifts in the rumen digestion. High dose (10 ml/l), on the contrary, reduces the total number of protozoa. The average dose load of 1 ml/l leads to an increase in digestibility to 72.63% and the concentration of infusoria to 555.56 thousand pcs/ml. Thus, based on the results obtained, it follows that the inclusion of the O. vulgare extract in a dose of 1 ml/l enhances metabolic processes in the rumen, leading to better digestion of feed. The dosage of 10 ml/l, the maximum of the tested, provided an increase in the concentration of the volatile fatty acids. However, when using 1 ml/l of O. vulgare, the most significant changes in the concentration of the volatile fatty acids occurred.

The effect of the diets with different ratio of easily digestible carbohydrates on milk productivity and milk quality of high-yielding Kholmogor cows during the milking period was studied. The research and production experiment on the cows was conducted in the Arkhangelsk region in 2022. Selection of animals in the control and experimental groups was carried out by the method of pair-analogues under the stall barn system. Two groups of cows participated in the research: experimental and control groups of 10 cows each. The experiment lasted for 100 days. Carbohydrate-protein mixture was used as a carbohydrate supplement to the diets of experimental animals in the amount of 1.5 kg per head per day. Selective milk quality control for mass fraction of fat, protein, lactose, dry matter, milk solids non-fat (MSNF), freezing point, urea and somatic cells were determined on a Bentley Combi 150 high-speed infrared milk analyzer at the Selective Milk Quality Control Laboratory. It was found that the sugar-protein ratio in the experimental group was twice higher (0.58) than in the control group (0.29), due to the presence of carbohydrate supplementation in the diet. The increase in milk productivity of the animals by 4.6 and 0.14% of the protein level in milk at inclusion of carbohydrate-protein mixture in the amount of 1.5 kg per one head per day in the diet was established. A 3.2% decrease in the level of urea in milk was recorded, indicating a more efficient use of amino acids by the animals in the process of metabolism at the same level of absorption of ammonium forms while increasing the level of simple carbohydrates in the diet. The positive effect of this additive on the content of dry skim milk residue, which increased in the milk of the cows of the experimental group by 0.128 absolute % (abs.%), was revealed. Application of the carbohydrate-protein mixture in the amount of 1.5 kg per one head per day and control over the quality of produced products will increase the milk productivity of cows, improve the quality of products, increase the productive longevity of dairy cattle.

The results of the studies of microbiological features of cultures of standardized and clinical strains isolated from biological material of the animals on the territory of Western Siberia belonging to Mycobacterium avium subsp. paratuberculosis (MAP) are presented. Microbiological studies of the pathogens consisted of the bacterioscopic method (staining of smears of cultures according to Ziehl – Neelsen) and the culture method (processing of biomaterial by the method of A.P. Alikaeva with subsequent sowing of the obtained sediment on Lowenstein-Jensen and Finn-2 egg nutrient media with mycobactin). In addition, biochemical tests with the cultures isolated from the material were used, including examination of colony growth at 30, 37 and 42 C, on the medium with sodium salicylate, with 5% sodium chloride, nitrate reduction, determination of amidase, catalase, arylsulfatase activity, hydrolysis of Tween-80 and a biological method consisting of intravenous infection with suspensions of standardized and clinical strains of non-linear white mice. The results of the studies showed that the cultures of clinical strains belonged to the 3rd group of mycobacteria according to the Runyon classification and their properties were identical to the standardized strain of M. paratuberculosis, which allows us to attribute them to mycobacteria of paratuberculosis. Antibiotic sensitivity studies of the standardized strain of M. paratuberculosis (Central-Lubinsky) and clinical strains revealed their susceptibility to all the drugs used in the studies. In a biological assay, mice infected with paratuberculosis pathogens had lower body weight than in the control groups. Autopsy revealed enlargement of lungs, spleen and liver, single purulent foci on liver, spleen and mesentery, and the liver was marbled, the mucosa of the small intestine is not changed. The growth intensity of cultures from the biomaterial (lungs, liver, spleen) was 2(++) to 3(+++) to 4(++++) points, the growth intensity of the cultures from the mucosa of the small intestine is 0(+/-) points. Bacterioscopic examination of smears of colony cultures of the studied pathogens isolated from the internal organs of mice of the experimental groups and stained by Ziehl – Neelsen staining showed the presence of single acid-fast granular bacilli arranged in groups or in the form of a "palisade", which is characteristic of the causative agent of paratuberculosis. The biological method of research on laboratory animals revealed the susceptibility of nonlinear white mice to the tested cultures and the possibility of reproducing experimental paratuberculosis infection on them.

One of the significant directions of scientific research in terms of improving the design of sowing machines and increasing their adaptability to modern requirements of automation is the creation of dispensers that provide adjustment of the seeding rate during the operation of the sowing machine. Specialists of the Siberian Research Institute of Mechanization and Electrification of Agriculture have developed a sample of a pneumatic sowing machine dispenser, which was used as a prototype in the study. The dispenser used allows for a smooth adjustment of the seed rate in accordance with the map task, as well as automatic shut-off of the seed supply to the seed line when the machine turns at the headland to prevent overconsumption of seeds and reseeding. The purpose of the research is to determine the design and technological parameters of the experimental dispenser of the pneumatic sowing machine. To achieve the set goal the following tasks were formulated: 1) to conduct a laboratory study of the process of seed metering in the experimental dispenser of the pneumatic seeding machine; 2) to determine the regularities of mutual influence of significant factors on the throughput capacity of the dispenser and describe them by regression equations. In accordance with the listed tasks the process of seed dosing on the laboratory unit was studied. In the course of experimental data processing, regression dependencies were obtained. According to the characteristics of the obtained equations, it is found that the most significant influence on the throughput capacity of the dispenser is the volume of the dispenser coil. Maximum performance of the dispenser is noted at rotor speeds in the range of 80–100 rpm. The highest feed rate and avoidance of spontaneous seed leakage from the dispenser into the seed pipe are achieved at a gate height of the dispenser discharge window within 2 cm. The results of the research can be used to finalize the design of the dispenser in order to use it as an actuator of the system of complex automation of the sowing unit.