Perm Research Institute of Agriculture is the legal successor of the Perm Provincial Experimental Station, founded in 1913. The article presents a brief outline of the Institute history, as well as the overview of the Institute research for the period since 1913 to the present. The main direction of the Experimental Station work, later the Institute, was the cultivation of poor sod-podzolic soils of the Urals. The bases of scientific research are long-term stationary experiments included to Russian Geographical Network of experiments with fertilizers. At present, the institute is moving to complex interdisciplinary research aimed at developing regenerative farming systems, developing a new direction in fodder production – the use of biologically active feeds, application of precision farming technique, the development of new technologies using methods and means of agrobiophotonics to increase the productivity of crops, monitoring and control of pathogens and pests, strengthening the environmental aspect in research.

Foot-and-mouth disease (FMD) is classified by the World Organization for Animal Health (OIE) as a Schedule A disease. Given the potential for rapid spread of the disease, all suspected cases should be reported and investigated immediately. Understanding the mechanism of FMD spread and control measures is key to outbreak investigation and allows the source of an outbreak to be traced along with potential routes of further spread. Foot-and-mouth disease is endemic in vast areas of Africa, Asia and South America. In 2022, the following countries remain unfavorable for FMD: Kazakhstan, Mongolia, China, Israel, Indonesia, UAE, Palestine, Algeria, Botswana, Zambia, Zimbabwe, Malawi, Mozambique, Tunisia, South Africa. In Russia, in 2022, foot and mouth disease was not registered. There are seven serotypes of foot-and-mouth disease virus: O, A, C, Asia 1, SAT 1, SAT 2 and SAT 3. Cattle, buffalo, sheep, pigs, goats, African buffalo, deer, yaks and other artiodactyls are susceptible to it. The two principle ways in which an animal can become infected are by inhalation of virus particles in the air, and by ingestion of food material containing virus particles, also through abrasions, contaminated instruments or artificial insemination. Up to 50 % of ruminant animals become persistently infected after clinical recover and termed a "carrier". Key risk factors for virus introduction are the introduction of a new animal into the herd with an unknown FMD vaccination status, seasonality, lack of vaccination, herd size. The cause of infection is often the uncontrolled or illegal movement of livestock. The main risk of FMD introduction comes from livestock, vehicles, people directly working with livestock susceptible to FMD, wild animals. The key principles of biosecurity are isolation of sick animals, cleaning and disinfection of premises and equipment. Foot-and-mouth disease is a major barrier to international trade in livestock and animal products, so countries free of the disease are taking increased precautions to prevent the virus from entering.

The article presents data on study of the productivity of potato early ripening varieties (Legenda, Russia; Red Scarlet, Netherlands) and middle-early varieties (Irbitskiy Russia; Gala, Germany) grown on aeroponic installations in artificial lighting conditions: three-tier adaptive installation (“Syntol” production) and single-tier installation produced by “Biological systems” plant. Potato plants were characterized by active growth and development. Their height ranged from 71.0 to 94.2 cm among the varieties, the number of leaves formed on one plant – from 23 to 31 pieces. The formation of mini-tubers was noted from the 46th day (Legenda variety) to the 53rd day (Irbitskiy variety). The first harvest was obtained at the 65th day in early varieties and at the 67th day for middle-early varieties beginning from planting of micro-plants on to the adaptation installation. The productivity of plants by varieties ranged from 123.0 g (Legenda) to 216.1 (Gala) g of mini-tubers per plant, output of mini tubers from 68.1 (Irbitskiy) to 105.2 (Legenda) pieces per plant, the mass of one mini-tuber ranged from 1.17(Legenda) to 2.73 g (Red Scarlet).

The article presents the results of studying potato accessions according to the accumulation and morphological properties of starch in tubers in the nursery of dynamic testing in agroecological conditions of the Kirov region (Volga-Vyatka region) in 2022. The objects of the research were 11 new hybrids bred by the Falenki Breeding Station – branch of the Federal Agricultural Research Center of the North-East named N.V. Rudnitsky. The early-maturing variety Udacha, the middle-early variety Nevsky, and the mid-season variety Chaika were used as standards. There have been identified hybrids with increased starch content (19 % and higher) on the 80th day of vegetation: early-maturing 172-13, medium-early – 165-00, 27-07, 13-18, mid-season – 182-13, 580-13, 252-18. The hybrids of the middle early group had the largest average size of starch grains: 165-00 (34.3±2.6 microns), 132-18 (36.0±3.0 microns), 233-12 (39.2±3.3 microns). Most of the hybrids had starch grains of regular rounded shape, accessions 233-12 and 232-12 – mostly irregular (angular) shape. In the course of the research, it was found that storing potatoes at the temperature of 3...4 ° C led to a decrease in the fraction of starch grains of very large size: in early-maturing varieties from 9.2 to 2.7 %, in middle early – from 13.5 to 5.0 %, in mid-season – from 9.6 to 3.2 %, which was due to starch resynthesis. As a result of the breeding work, promising potato hybrids of various maturation periods have been identified for transfer to state variety testing with improved agronomic traits, including high potential productivity: early-maturing 172-13, middle-early 233-12, mid-season 182-13 and 580-13.

Meteorological conditions were monitored for the period "May-August" in the Kirov region (Volga-Vyatka region) from 2008 to 2022. An increasing trend of the sum of precipitation and hydrothermal coefficient (НTC) values and a descending trend of the sum of effective temperatures was established. By the example of early-ripening (Iren, Bazhenka) and middleripening (Priokskaya, Simbirtsit, Margarita, Kamenka) varieties of spring wheat, the level and direction of variability of the main agronomic traits by changing the values of the НTC have been determined. In early-maturing varieties with an increase in the НTC of the growing season the content of protein and gluten in the grain significantly decreased, and the following increased: yield, duration of vegetation, plant height, ear density, mass of 1000 grains, density of the productive stem, the nature of the grain and the indicator of the gluten index. The elements of ear productivity were maximally expressed in the years optimal in terms of moisture. The reaction of medium-ripened varieties was similar according to the greater number of traits, except for the number of grains per ear, the weight of the grain per ear and the plant, the nature of the grain. By means of the correlation analysis, the influence of meteorological factors on the development of traits of spring wheat both for the entire growing season and for individual months has been studied. A high dependence of the duration of the growing season and the protein content in the grain on the sum of effective temperatures for May-August (r = 0.64...0.77) was revealed. The amount of precipitation made a significant contribution to the formation of traits only in critical phases of plant development. The analysis of regression equations obtained using 11 variables (weather factors by months) with a time sample size of 15 years showed that an increase in the amount of precipitation in June by 10 mm led to an increase in yield by an average of 0.13...0.14 t/ha, and a decrease in the average daily temperature of August by 1 °C provided an increase in yield by 0.23...0.26 t/ha. The duration of the growing season decreased in June by 2.2...2.4 days with 1 °C increase in the average temperature; in July – by 2.3...3.0 days; in August – by 1.3 days. The protein content in the grain most of all depended on the average daily temperature in June, with of 1 °C increase the amount of protein raised by 0.85...0.87 %.

In the conditions of the Moscow region in 2019-2022 the effectiveness of funicides of new chemical classes in the potato protection system against rhizoctoniosis, late blight and alternariosis was studied, taking into account the different resistance of varieties (Gulliver, Grant, Sante) to diseases. Potato tubers were treated with the preparation Idikum, SC before planting, its biological effectiveness in reducing the incidence of rhizoctoniosis in the full germination phase was 76.7-95.7 %. It was found that the effectiveness of the preparation depended on the degree of disease development, the stability of the variety and the phase of crop development. In addition, when etching the planting material with Idikum, SC, there was no population of rhizoctosis sclerotia and the spread of dry rot on tubers of the new yield significantly reduced (1.6-5.0 times) compared to the control. The proposed scheme of potato protection in conditions of epiphytotic development of late blight and early blight based on combined chemicals Metaxil, SP, Inside, SC with contact fungicides Raek, CE, Talent, SC, Tirada, SC showed high efficiency in reducing harmfulness of the diseases, which allowed to extend the growing season of plants, to ensure a higher yield of potatoes, its marketability and quality. The use of preparations provided an increase in yield by 36.3-47.5 %, depending on the prevailing weather conditions of the growing season and on the variety in relation to the control (without treatment). It has been established that the biological effectiveness of the protection scheme in reducing the degree of late blight and early blight increased from susceptible to relatively stable varieties and, accordingly, this trend continued with an increase in yield. Higher increases were obtained on unstable varieties Gulliver and Sante (10.6-13.5 t /ha, or 45.7-56.0 %), lower – on the relatively stable variety Grand (7.8 t/ha, or 36.0 %). The contribution of the application of the protection scheme to the overall variation of gross and marketable potato yields was 76.5-81.0 %, gene-type - 7.9-12.5 %, the interaction of these factors – 3.7-4.7 %.

Winter rye is an important crop of the Non-Chernozem belt of Russia, the productivity of which depends on the use of fertilizers. The paper presents data on the agronomic and economic efficiency of cultivating Falenskaya 4 winter rye under conditions of long-term use of mineral fertilizers. The studies were carried out in 2019-2021 in Perm Region on sod-podzolic heavy loamy soil in a long-term stationary experiment based on a reduced factorial design (6x6x6) with a wide range of doses and NPK ratios. The highest yield in 2019 was obtained in N30P120K120 variant (3.07 t/ha), the highest payback of mineral fertilizers by grain was noted in N90 and N30P30K30 variants (6.00 and 5.69 kg of grain). The highest yield and payback of grain in the conditions of 2021 and for two years of research in average was obtained in the variant N90: in 2021, 3.01 t/ha and 13.96 kg of grain, for 2 years average – 2.95 t/ha and 9.82 kg of grain. The efficiency of nitrogen fertilizers has been proved by a regression equation for two years average, phosphoric and potash fertilizers did not have a significant effect. The rise in the yield increase occurred up to a nitrogen dose of 90 kg/ha and amounted to 0.42 t/ha at N90. The highest payback by grain was noted among nitrogen treatments – by N30 (7.3 kg of grain), with each increase in doses by 30 kg/ha, this indicator decreased linearly by 1.3 kg. The highest profitability over the years of research was obtained in the variant without fertilizers– 60 %, over two years in average. The profitability of using N90 was higher compared with the control only in 2021 – 50 % versus 43 %. All the studied doses of nitrogen used separately provided positive profitability, but the most cost-effective was the use of N30 and N60 – profitability was 52 and 45 %, respectively.

The yield and quality parameters of potato tubers of Gala variety were determined in the conditions of the Middle Urals in 2020 and 2022 in long-term stationary experiment after prolonged application of NPK increasing rates (30-60-90-120-150 kg a.i.). The application of NPK by 60 kg a.i./ha and more promoted the potato yield raise by 1.1-1.3 times in 2020 and by 1.3-1.5 times in 2022 compared with the control variant without fertilizers (21.4 and 14.4 t/ha by years, respectively). The lowest dry matter content over the years of research was noted at the maximum dose of N150P150K150 mineral fertilizer in the experiment– 15.6 % in favorable weather conditions of 2020 and 19.4 % in the dry 2022. The starch content in potato tubers did not depend on the dose of applied mineral fertilizers and varied in 2020 in the range from 11.1 to 13.8 %, in 2022 – from 14.4 to 16.3 %. In potato tubers the content of crude protein in the wet mass increased from 1.32 to 1.90 % in 2020 and from 1.80 to 2.65 % in 2022 to the weight of wet mass with an increase in the dose of NPK from 30 to 150 kg/ ha active substance. The sugar content in 2020 was 0.58-0.83 % for natural humidity, in 2022 – 0.23-0.47 %. The fiber content in potato tubers did not depend on the doses of applied mineral fertilizers. The application of increasing doses of NPK did not lead to exceeding the permissible value of the nitrate content in fresh potato. According to a comprehensive assessment of the quality of tubers, potato yield, obtained under given conditions, was suitable for the production of low carbohydrate potato products and for fodder purposes.

The paper presents data on a three-year study (2020-2022) of the effect of a liquid-phase biological product containing iron nanoparticles (LPB-Fe), obtained by biosynthesis using green tea extract, on the yield of potatoes of the Skarb variety and the activity of soil enzymes under the conditions of Tverskaya areas. Comparative efficiency of LPB-Fe, the original LPB biopreparation, solution of iron nanoparticles Fe NPs was studied in the field against the background of NPK application. The results showed that the maximum productivity (669.1 g/bush) of potatoes was obtained by foliar treatment of vegetative plants with a 1% solution of LPB-Fe – 16.9 % more than the control variant (NPK background). With the separate use of a 1% solution of LPB and a 1% solution of Fe NPs, the productivity was 628.4 and 550.6 g/plant, respectively, which indicates an increase in their impact on potato plants when used together as part of LPB-Fe. It was noted that the activity of invertase correlated with the content of humus in the soil, and the activity of the protease correlated with the content of readily hydrolysable nitrogen. In addition, the study of the activity of enzymes in the soil under potatoes (catalase, dehydrogenase, invertase, cellulase and protease) showed that they have a significant impact on the yield of potatoes at different stages of the growing season with various technological methods of using biological preparations. For example, when treating potato tubers at the seedling stage, an inverse relationship was found between catalase activity in the soil and yield: the higher the enzyme activity, the lower the yield (correlation coefficient is -0.82). And in the case of cellulase, with the same technological method, on the contrary, a direct dependence is observed: the higher the activity of the enzyme in the soil at the seedling stage, the greater the yield (correlation coefficient is 0.72). Thus, when soil and plants are exposed to Fe-containing biological products, the activity of enzymes responsible for the transformation of the main biogenic elements (carbon and nitrogen) and redox processes occurring in the soil changes, which ultimately leads to a change in soil fertility and, therefore, either decrease or increase of crop yields.

method, on the contrary, a direct dependence is observed: the higher the activity of the enzyme in the soil at the seedling stage, the greater the yield (correlation coefficient is 0.72). Thus, when soil and plants are exposed to Fe-containing biological products, the activity of enzymes responsible for the transformation of the main biogenic elements (carbon and nitrogen) and redox processes occurring in the soil changes, which ultimately leads to a change in soil fertility and, therefore, either decrease or increase of crop yields.

In the conditions of the Chuvash Republic in a long-term stationary experiment there has been studied the effect of crop rotations (grain- fallow and green manure) and methods of primary tilling of soil (by the plow PLN-3-35 to the depth of 24-26 cm; by the combined unit KOS-3.0 to 14-16 cm; by the disc header BDM-4-3.2 to 10-12 cm without autumn tilling) on the cellulose-decomposing activity of the soil by the method of setting up flax linen and on the crop yield. The article provides 2016-2020 data. It has been established that plowing increased the total soil porosity (55.3…63.5 %) and provided maximum decomposing of flax linen (42.9…51.3 %). Absence of primary soil tilling led to the statistically significant decrease in the porosity (50.8…59.3 %) and cellulose-decomposing activity (36.1…43.9 %). Maximum yield of crops in crop rotation was obtained by cultivation according to traditional plowing. When replacing plowing by subsoil tillage the use of combined stubble cultivator KOS-3.0 was the best variant. Primary tillage of soil to the depth of 14-16 cm using KOS-3.0 unit instead of plowing led to the significant yield decrease (by 0.29 t/ha) of spring vetch only. Among other cultures of crop rotation there was no significant yield decrease. Complete rejection of autumn soil tillage led to 16-25 % yield loss in grain crops. Plowing to the depth of arable layer (24-26 cm) as primary autumn tillage of soil increased the fertility indicators of dark-gray wooded soil (its total porosity, cellulose-decomposing activity) and yield of cultures in crop rotation. But when changing over to resource saving technologies for primary autumn tilling of soil under grain crops the combined unit stubble cultivator KOS-3.0 should be used.

The article summarizes the 2020-2021 research results, obtained in a field stationary experiment on leached chernozem in the Republic of Mordovia. The object of the study was spring barley of the Zazersky 85 variety. In its sowings the effectiveness of separate and joint use of the Forsazh (micro) preparation with various doses of mineral fertilizers was studied, including against the background of liming of the soil by 0.5 and 1.0 h.a. in 1999-2000. On average, for two years in the variant without the use of chemicals, the crop yield was 1.82 t / ha. The effect of fertilizers (P40K40, N40-60-80P40K40) was estimated by an increase in the yield of 0.10, 0.40-1.02 t/ha (LSD05 = 0.03 t/ha). The payback of 1 kg a.i. of mineral fertilizers with additional income increased with the rise in the doses of fertilizers applied - 0.94, 1.08, 1.19, 1.38 rubles/rub, respectively. The use of mineral fertilizers significantly increased the mass of 1000 grains and the natural weight of barley grain by 0.6-2.3 g and 9-33 g/l, respectively, and the Forsazh preparation by 0.2 g and 3 g/l. The recommended dose of mineral fertilizers for barley N80P40K40 provides the yield of 2.84 t/ha. Additional use of the Forsazh (micro) preparation will improve the technological indicators of grain quality.

The direction of the breeding process in herds and populations of dairy cattle breeds based on the actual indicators and variability of the trait is one of the main factors that allows to determine the effectiveness of breeding measures. As the initial material for the research there were taken the data of breeding records (n=681) of Ayrshire breed cows of the agricultural complex "Maysky" of the Vologda region. The number of cows was distributed by generations (195 cows with the first incomplete lactation, 177 cows with the first completed lactation, 130 cows for the second lactation, 179 cows for the third lactation and older). According to the research results, the superiority of the actual indicators for the live weight of heifers in animals of modern generation in early age periods was from 28 to 39 kg. Consequently, with each new generation, animals have better development indicators, as evidenced by the indicators of variation (variability) of the live weight of heifers in the early age periods of weak and moderate Cv = 5.3 to 10.6 %, depending on generation. The reduction of the age of the first insemination of heifers to 13.4 months (-2.2 months) and the first fruitful insemination to 14.0 months (-2.1 months) in animals from full-age to the first incomplete lactation was revealed. A targeted selection of cows was carried out in the herd according to the level of milk productivity of mothers after the first lactation - the selection efficiency was 977 kg of milk, according to the highest - 456 kg. The selection of breeding bulls was carried out according to the level of productivity of the breeding stock, however, it should be noted that the intensity of selection in cows for the incomplete first (10968 kg of milk) and first lactation (10635 kg of milk) is reduced compared to cows for the second lactation (11417 kg of milk). Consequently, in herds and populations of dairy cattle breeds, in order to achieve genetic progress in productivity in the next generation, it is necessary to determine the direction of the breeding process.

The article presents the results of the assessment of the biological usefulness of feed according to the control tests of milk. Scientific research was carried out in LLC "Minskoye" of the Kostroma district of the Kostroma region on a population of 369 cows of the Kostroma and Black-and-White breeds according to the seasons of the year. The authors found that in terms of the level of digestible protein in lactating cows, there is an imbalance in almost all seasons of the year, so most animals are prone to diseases associated with metabolic disorders. The level of rumen acidity in animals of the Koroma breed was more stable (pH = 6.2-6.4) in all seasons of the year, which indicates a lower likelihood of developing acidosis, in contrast to Black-and-White breed cows. Based on the indicators of milk control tests, insufficient supply of raw protein to cows of the Kostroma and Black-and-White breeds during the milking period was established. The highest daily milk yields (more than 30 kg of milk) were obtained from cows in the first and second periods of lactation in all seasons of the year. In animals with a level of availability of digestible protein of 10.3-10.9 g/MJ, there is a normal ratio of fat: protein (1.26:1), with a profitability level of 66.11%, while animals with an insufficient level availability of digestible protein of 10.2 g/MJ and less, had the level of profitability of milk production 73.93 and 86.44%, respectively. When the level of availability of digestible protein is more than 11.0 g/MJ in animals, the likelihood of acidosis increases. Evaluation of the biological value of feeds according to control tests of milk during the period of control milkings will allow monitoring the energy and protein nutrition of animals.

The effect of using enzymatic and probiotic preparation “Rumit” in feeding the Ayrshire cattle has been studied. The objectives included the analysis of biochemical blood parameters of newborn cows, research of the feed additive action on the activity of rumen microflora and milk productivity level, as well as calculation of economic efficiency of the probiotic. To implement the objectives the experiment was carried out in the period from March to July 2021 on the basis of OOO “Zarya” of Chagodoshchensky district of the Vologda Oblast. During the experiment there were formed two groups of the Ayrshire cattle of 15 cows each at the beginning of lactation, selected by the method of balanced groups. Cows of the control group received the farm diet, and the experimental group was given an additional 50 g per head per day of probiotic “Rumit” in the daily feeding. The duration of the experiment was 90 days. Use of the probiotic in the experimental group contributed to the increase of rumen microflora activity by 28 % (P≤0.05). In the analysis of biochemical blood parameters of the experimental animals, compared with the control group, there was an increase in total protein by 14.3 % (P≤0.05), urea decreased by 19 % (P≤0.05) and bilirubin fell by 21.3 % (P≤0.05). There was an increase in cows’ milk productivity in the experimental group by 6.7 % and, as a consequence, a 5.2 % reduction in the cost of energy feed units for production. Additional profit from selling milk in the experimental group was 37.32 rubles per head per day.

The purpose of the research is to study the composition of biologically active compounds of the experimental biological supplement Fitostimplus and its influence on the biochemical parameters of the blood of calves of the milk growing period, body weight gain, safety. In the experiment Holstein calves starting from the age of 3 days were used during 2 months. The results of studies of the phytobiotic for the presence of biologically active substances showed that it contained 13 different flavonoids and their glycosides, 7 ecdysteroids. As the main flavonoids there were identified luteolin, quercetin, quercetin-3-methyl ether, apigenin, kaempferol, and as ecdysteroids - ecdysten, inocosterone and augasterone C. The total concentration of the studied extractives (flavonoids, ecdysteroids) in terms of dry product corresponded to 3.594 mg/g. The concentration of lactic acid microorganisms in Phytostimplus was 4×106 CFU/g. In the experiment on calves (n = 5 per group) it was found that after daily oral administration for 60 days Phytostimplus in doses of 1.0; 2.0; 3.0 grams per head, the average daily gain in live weight in the experimental groups exceeded that in the control by 6.3-27.7 %. The best indicator of the average daily gain in live weight of calves was noted with the introduction of 2.0 and 3.0 grams (27.7 and 18.2 % higher than in the control, respectively), safety in all groups was 100 %. A month after the start of the experiment, the phosphorus index in the blood of calves in all experimental (from 3.1±0.07 to 3.4±0.02 mmol/l) and control (3.1±0.01 mmol/l) groups exceeded reference values by 6.9-17.2 %. At the end of the experiment, the phosphorus index in the experimental (from 2.7±0.22 to 2.8±0.07 mmol/l) and control (2.6±0.01 mmol/l) groups returned to normal. Glucose in the experimental and control groups (from 5.3±0.2 to 5.9±0.1 mmol/l) was 15-28.2 % higher than the reference values. Other studied biochemical parameters in the experimental groups: ALT (from 13.4±1.6 to 19.9±2.2 units/l), AST (from 56.3±3.2 to 63.3±4.8 units/l), total protein (from 62.0±0.1 to 65.0±0.1 g/l), albumins (from 39.3±1.4 to 41.5±2.4 g/l), creatinine (from 64.8±3.5 to 72.8±6.6 µmol/l), urea (from 2.7±0.16 to 3.6±0.3 mmol/l)– did not go beyond the physiological norm. Thus, by the end of the experiment, Phytostimulus contributed to an increase in the average daily gain of calves in comparison with the control. The effective doses of Phytostimplus for calves of the milk growing period were established, which, in terms of the main substance, corresponded to 2-3 g/head per day.

An experiment was conducted in the conditions of an industrial complex specializing in the intensive fattening of young cattle, to study the development patterns of respiratory and gastrointestinal pathologies in calves with a history of previous proventriculus dysfunction. The object of the research were calves aged 120 days, which were divided into three groups: control, and two experimental groups - with a difference in using or the absence of phytosorbent. The diet included cereal hay and compound feed (CP 21.5%) according to the norms and regimen of feeding, for animals of this age. It appeared that for calves shortening of the adaptation period to the consumption of a large amount of compound feed had a negative impact on the rumen contractile function and the processes of digestion in it with the formation of a complex of symptoms of frothy tympany and rumen acidosis. After a course of appropriate treatment, the specific symptoms of these pathologies of the rumen disappeared, but the imbalance between the depression of symbiotic and activation of abdominal digestion remained, with the formation of a constant pre-threshold level of local autointoxication. The transfer of animals to the technological diet activated the processes of rumen metabolism and increased biochemical imbalance, which caused the progression of the endogenous intoxication syndrome and vegetative dystonia with a corresponding increase in the risk of developing respiratory and gastrointestinal pathologies. The use of a combined native premix based on the enterosorbent Rigatirin against the background of residual pathological phenomena after proventriculus dysfunctions reduced the level of toxic substances in the rumen, which excluded the generalization of autointoxication with an increase in the functional load on the digestive organs. As a result, the mechanism of pathogenetic integration (predisposition) formation in the body was leveled with a corresponding decrease in the incidence of the lungs, rumen and intestines. As a result, the mechanism of pathogenetic integration (predisposition) formation in the body was leveled, which caused a 6.7-fold decrease in the level of morbidity in animals and a 22.9 % increase in their growth.

The need to use such propulsion devices in mobile agricultural power units is substantiated. The relevance of this development based on global trends is shown. The purpose of the research is to develop the design, to evaluate strain-stress state and functional characteristics of undercarriages of agricultural tractors with replaceable half-tracks. An experimental design of the replaceable tracked undercarriage was developed and manufactured, modeling of loading modes was performed, calculations were carried out by the finite element method of the stress-strain state of structural elements according to 6 load schemes – tractor parking on a flat horizontal surface; movement with maximum traction force; parking across a 30° slope for the upper track; parking across a 30° slope for the lower caterpillar; driving into an obstacle with a deviation of 15°; driving over obstacles based on the central rollers. It was determined that the selected structural material, by the above mentioned loading modes ensure the operability of replaceable tracked undercarriage. Calculations were carried out to check the adequacy of the developed mathematical model using field tests in testing ground of FSAC VIM. It was determined that the maximum stress-strain state of the frame structure of a replaceable tracked undercarriage for all types of loading did not exceed 100 MPa. This provides a two-fold margin of safety in terms of fluidity of the structure, taking into account the characteristics of the selected material. In the maximum loaded state - parking across a slope of 30° - the highest stress on the upper track is 161 MPa, which corresponds to a safety margin of 1.45. The deformation of the bearing assembly was no more than 4 mm, which is allowed by the design of the drive assembly and the caterpillar.