Purpose: to study the effect of oregano and marsh cinquefoil extracts on the hematological and biochemical profiles of laboratory mice.

Materials and methods. The article presents a study of the effect of MC and O extracts on laboratory mice. The raw materials for the production of extracts were rhizomes of MC and above-ground parts of O collected in the Altai Krai. The effect of the extracts was studied on 54 two-month-old ICR mice of different sexes. Three experimental groups were formed: control, experimental with O extract (20 mg/kg) and experimental with MC extract (20 mg/kg). The following hematological and biochemical parameters were studied: the content of erythrocytes and hemoglobin, hematocrit, average volume of erythrocytes, the content of leukocytes and lymphocytes, the content of calcium, phosphorus, cholesterol, urea, glucose, triglycerides, total protein and albumin.

Results. As a result of the study, it was revealed that the studied extracts are capable of having a significant effect on such metabolic parameters of laboratory mice as the content of glucose, cholesterol and total protein. The most significant effect was observed in female mice consuming the MC extract. Based on the results obtained, it was concluded that it is advisable to further study MC and O extracts as components for the development of hyperglycemic, hypolipidemic and restorative drugs based on medicinal plants.

The aim: to study the dynamics of the concentrations of estradiol, estriol and estrone, their ratios in the studied period of the ovulatory cycle and the connection with the size of egg yolk.

Materials and methods. The material for the study was chickens of the Pushkin breed, in the amount of 36 birds. at 36 weeks of age. The chickens were kept in individual cages. Light mode — 14C:10T. Watering — nipple, temperature in the poultry house and feeding - in accordance with the standards adopted by the Central Collective Use Center of the All-Russian Scientific Research Institute of Growing Animals "Genetic collection of rare and endangered breeds of chickens". Over the course of 7 days, eggs from 96 chickens of 30 weeks of age were assessed by the weight of the egg, yolk, white, shell - using electronic scales Mertech M-ER 122ACF(JR) with an accuracy of 0,01 g. Eggs were counted and assessed individually: From each hen, at least 3 consecutively laid eggs were examined the next day after collection. Based on the data obtained from assessing chickens based on the quality characteristics of eggs and productivity, 36 birds with egg yolk weights M-0,5σ, M±0,45σ, M+0,5σ were selected. Blood from the studied chickens was taken in the morning and during the day on an empty stomach to simultaneously determine the concentrations of estradiol, estriol and estrone 2 hours before laying eggs and within 4 hours after laying, with an interval of 1 hour. In order to obtain serial blood samples from chickens for Dynamic studies of estrogens included the installation of peripheral venous (intravenous) catheters. The concentration of estrogen in the blood plasma of chickens was determined by ELISA.

Results. The concentrations of individual estrogenic hormones change during the 6 hours of the studied period of the ovulatory cycle, periodically increasing and decreasing, while the fluctuations coincide only in two periods after the egg is laid: after 1—2 hours — a rise and 2—3 hours — a decline. Of the six studied periods of the ovulatory cycle of chickens, the time period of practical interest is 2—1 hours before egg laying, when the ratio of estradiol:estrone was 7,4:1, estriol:estrone — 7,9:1 and estradiol:estriol — 1:1. During this period, a positive significant correlation was revealed between the estradiol:estrone ratio and the yolk mass of chicken eggs — +0,55 (p <0,05). Also, in the established period, the highest concentration of estradiol (1,52±0,12 nmol/l), estrone (0,29±0,04 nmol/l) was simultaneously observed compared to other periods, and the lowest concentration of estriol (1,67± 0,16 nmol/l). A positive correlation was determined between estradiol and estrone — +0,68 (p <0,05) and estradiol and estriol — +0,71 (p <0,05).

Conclusion. In the period 2—1 hours before laying eggs, the effect on the body of chickens of estrogenic hormones in the ratio estradiol: estrone 7,4:1, estriol:estrone – 7,9:1 and estradiol:estriol — 1:1 leads to inactivation of synthetic systems, providing intensive formation of ovogenic substances by the liver (vitellogenin, lipoproteins), and the transfer of vitellogenic material into developing follicles.

Purpose: to evaluate the effect of a vitamin-mineral complex with a probiotic on the histological structure of the gastrointestinal tract tissues of budgerigars in dynamics.

Materials and methods. The object of the study were budgerigars aged from 60 to 180 days. According to the principle of pairs-analogues, 3 experimental and a control group of 20 birds each were formed from clinically healthy budgerigars. For the purpose of the experiment, complete granules were created containing a basic grain-seed diet and a complex consisting of a probiotic, vitamins and minerals. Bacillus Subtillis 5 mg per 100 g of live weight was used as a probiotic. For histological and histochemical studies, tissue pieces measuring 0.5 x 0.5 x 0.5 cm were selected. In each section, an assessment of at least 10 fields of vision was given.

Results. As a result of the experiment, lasting 45 days, a gradual increase in the probiotic mass was noted in the gastrointestinal tract of budgerigars on the 15th and 30th day. Complete release of the body from the probiotic was observed on the 30th day after stopping the administration of the granulated complex. No changes in the histological structure of the liver were revealed. Positive changes in the intestine and stomach were noted, such as an increase in the density of villi and the height of the epithelium, folds, crypts and tubular glands. These changes are reversible, due to the temporary effect of the vitamin and mineral complex with a probiotic.

Purpose: to identify CNV regions (CNVRs) and identify potentially specific CNVs in Sal sheep.

Materials and methods. The research was carried out on 48 Salsk breed sheep. Genotyping was performed using high-density microarrays Ovine SNP 600 K BeadChip array (Illumina, USA). DNA copy number variation (CNV) searches were performed using PennCNV software based on the Oar_v3.1 reference genome.

Results. We identified 4585 autosomal CNVs in 48 Sal breed sheep. The average CNV length was 92,3 Kb. 21,1 % of the total number of CNVs are less than 50 Kb in size. On average, from 65 to 138 CNVs were identified per animal. 527 autosomal CNVRs were obtained, representing 54,77 Mb of the entire sheep genome. The proportion of chromosomes covered by CNVR varies by chromosome, from 0,5 % on OAR25 to 9 % on OAR24. Analysis of CNVR in the ENCEMBL system revealed 42 genes in which CNVRs are localized; the remaining CNVRs are located in intergenic regions. Comparison of the identified CNVRs with sheep QTLs from the Animal QTL database showed that 39,24 % of the genes were responsible for reproductive traits, and 20,25 % were responsible for wool-related traits.

Conclusions. Functional annotation of CNVRs localized in genes and intergenic spaces was carried out and the total number of detected CNVRs in the QTL database was analyzed. The results showed that CNVs are localized in genes associated with selection-significant traits in sheep.

Purpose: to study changes in the most important metabolic parameters in case of dyspepsia in calves.

Materials and methods. Two groups of calves of 8 heads each, aged from 6 to 14 days, were formed. The first group included calves with signs of dyspepsia, who, in addition to diarrhea syndrome, had decreased appetite, weakness, and signs of abdominal pain. At the time of the study, the duration of the illness was 2-4 days. The second (control) group included clinically healthy animals of the same age. Blood was taken from the calves from the jugular vein in the morning before feeding. Blood serum was examined in a clinical biochemical laboratory using standard test systems to determine biochemical parameters.

Results. In calves with dyspepsia, a significant decrease in the concentration of triglycerides by 1,8 times, cholesterol by 1,57 times, total protein by 5,5 % and albumin by 12,3 % was revealed. They also revealed a significant increase in the activity of transamination enzymes — ALT (2,6 times) and AST (1,6 times), which may indicate both damage to hepatocytes and the induction of enzymes to accelerate transamination reactions in order to meet energy needs calf body. The studies did not reveal significant changes in the concentrations of urea, creatinine and bilirubin.

Conclusion. Studies have revealed metabolic changes that occur due to decreased absorption of nutrients in the intestines. Damage to the intestinal mucosa leads not only to a deterioration in the absorption of nutrients, but also to the penetration of proteins, primarily albumins, into the intestinal lumen and their removal from the body into the external environment. Redistribution of metabolic pathways to ensure homeostasis plays an adaptive role, but subsequently can have a negative role in the processes of growth and development of the calf’s body.

This work is aimed at studying the etiology, prevalence, diagnosis, treatment of uterine cysts and their difference from the embryo during ultrasound examination. Endometrial cysts are often the cause of infertility and indicate pathological changes in the uterus, occurring in older mares. There are two types of uterine cysts: endometrial glandular cysts and lymphatic lacunar cysts. Endometrial cysts are usually smaller than lymphatic cysts located in the endometrium and are composed of endometrial glands. Lymphatic cysts cause obstruction of the lymphatic channels and appear as single or multilobular structures. Cysts can result from chronic degenerative changes in the endometrium and their clinical significance varies. For example, in terms of fertility, their influence is related to size, conditioning, content and location in the uterus. The presence of small cysts often indicates matte structures. In addition, larger or more active cysts have an impact on the course of pregnancy. Single large or small cysts can lead to embryonic pregnancy failure, which is the most difficult recognition of maternal pregnancy. Careful testing methods can effectively monitor the mare's condition and ensure the prospects for a successful pregnancy. This pathology is diagnosed using rectal and ultrasound examinations. There are many treatment options: they can be removed by surgery, hysteroscopic biopsy forceps, snare, laser (diode, CO2 or Nd/YAG laser), electrocoagulation or injection of 70 % ethanol (sclerotherapy method). But unfortunately, many cysts are prone to relapse. Sometimes the presence of cysts can interfere with the diagnosis of pregnancy or lead to an erroneous diagnosis of “multiple pregnancy”, since cysts under ultrasound exposure appear as filling fluid structures in the endometrial lumen. For this reason, it is important to be able to diagnose, predict consequences and treatment options in the mare.

Purpose: to assess the activity of AST, LDH and HBDH enzymes in relation to different levels of total creatine phosphokinase activity to understand the degree of their diagnostic value in determining the severity of myopathy in horses.

Materials and methods. For the study, statistical processing of a data array of the results of a biochemical study of blood serum from 247 horses was carried out. Taking into account the reference intervals of CPK activity, all results were ranked by increasing creatine phosphokinase activity and divided into four groups. In each group, the average values for AST, LDH and HBDH were calculated, and the degree of significance of intergroup differences was calculated using the Student's t test. The correlation between the activity of the enzymes AST, LDH and HBDH with the activity of CPK in each group was also assessed.

Results. An increase in the activity of creatine phosphokinase in horses by 59,4—409,6 % is accompanied by an increase in the activity of the enzymes AST by 14,5—77,2 %, LDH by 17,8—33,0 % and HBDH by 17,1—27,1 %. When comparing Pearson's correlation coefficients across the entire study sample, a significant direct relationship is determined between CPK and AST and a moderate direct relationship when comparing CPK with LDH and HBDH. Calculation of the Pearson coefficient in each of the studied groups showed different degrees of correlation between the creatine phosphokinase indicator and other enzymes, but in all cases positive. A study of the percentage contribution of HBDH to the total lactate dehydrogenase activity showed an inversely proportional relationship with respect to the activity of creatine phosphokinase, which indicates massive muscle damage with switching energy metabolism in them.

Conclusion. The conducted studies made it possible to more deeply understand the cause-and-effect relationships of changes in the activity of enzymes that are specific to muscle tissue in connection with the severity of myopathy. The data obtained can assist veterinary specialists in analyzing the results of biochemical blood tests in horses.

Purpose: to study the morphological and economically useful traits of domestic reindeer (Rangifer tarandus L.) in the forest-tundra zone of the Far North-East of Russia.

Materials and methods. The study used zootechnical information from annual reports on completed research projects by employees of the Laboratory of Selection and Breeding in Reindeer Husbandry of the Magadan Zonal Research Institute of Agriculture of the North-East for the 1970-1980s and 2000s. The model for the research was the reindeer population of the Markovsky state farm, typical for the forest-tundra zone of the North-East. The area of ​​reindeer pastures on the farm exceeded 5 million hectares, with 142.8 hectares per head. The average size of the production herd was 2,500 individuals.

Results. The article presents data on morphological and economically useful traits of reindeer in the forest-tundra of the North-East — a pasture-geographical space on the border of the ranges of two large groups of reindeer — tundra and taiga. In the Markovsky state farm, typical for the forest-tundra zone, out of 35 thousand reindeer in the main herd, 25 % were Even, 44 % were Chukchi and 31 % were crossbred Chukchi-Even animals. In the forest-tundra, a hybrid population of reindeer was formed as a result of crossing two sympatric populations of the Even and Chukchi breeds. The intermediate phenotype had characteristic differences from the original breeds in morphological traits — color, exterior and constitution (linear measurements, body indexes), and meat productivity indicators. The conclusion is made about the origin of the forest-tundra ecotype based on hybrids from crossing sympatric populations of Chukchi and Even reindeer of different generations, backcrossing, introgression, stabilizing selection, microevolution under the influence of natural conditions and anthropogenic factors.

The purpose of this study is to establish the influence of average daily gain (ADG) of heifers at different periods of their development on the age of 1st insemination (A1ins) at 12, 13, 14, 15, 16, 17, 18 months and older and milk yield of first-calving cows for 305 days of lactation according to a sample (n=1289) formed from the Seleсs database of one of the breeding plants in the Leningrad region for breeding the Ayrshire breed of dairy cattle. On average for the sample, the correlation coefficient of milk yield with A1ins indicates a negative relationship between these two characteristics (-0.218), a positive correlation of milk yield with live weight of 1st insemination LW1ins (+0.101) with a negative connection with ADG (-0.110). It was revealed that in all age groups of heifers there is a decrease in ADG at the age of 2 months, and the intensity of further development of heifers depends on ADG at the age of 3, 4, 5 months, at a level of over 800 g, contributes to the achievement of A1ins from 12 to 14 months. At the same time ADG at the age of 9—12 months should be at least 800 g. However, even with ADG 800—900 g at the age of 3—5 months, but when these indicators decrease at 9—12 months below 800 g, A1ins increases to 15—16 months. Low ADG at the age of 3—5 months and at the level of 600 - 700 g at the age of 9—12 months increases A1ins to 17 months and older. Thus, for an earlier A1ins and a high level of productivity in the 1st lactation, one should pay attention to the development of heifers at the age of 3—5 months, maintaining the ADG at a high level (more than 800 g) and avoid low weight gain at 9—12 months (less than 800 g).

Providing the population with quality food products is currently relevant. High-tech production of meat and dairy products requires breeding animals with high genetic potential. The main role is given to bull sires, since they are responsible for the constant reproduction of the breeding stock, which depends on the non-stop renovation of the herd with high breeding value’s calves.  Management of growing and breeding of young bulls can directly affect the reproductive function of sires and the physiological health. The article provides analytical data based on literary sources containing research by various authors on this topic, and reviews methods and technologies for keeping breeding bulls on various farms in the Russia and abroad. Currently, there is a many problems of getting high-quality breeding young bulls to an artificial insemination center. Currently, there are problems with obtaining high-quality breeding bulls of the enterprise. There are animals with abnormal development of the musculoskeletal system, joints, hooves, with signs of osteomalacia, etc. Such animals require additional costs for veterinary and breeding services. The quality of the sperm products they produce often does not comply with state normative. The reason is related either to the choice of maintenance technology or feeding technology. It is necessary to competently organize management, breeding and veterinary work in farms that are purposefully engaged in breeding young animals.

Purpose: to conduct a comparative description of the productive and morphological characteristics of domestic reindeer of the Nenets and Evenki breeds.

Materials and methods. Study of the morphological, behavioral and reproductive characteristics of domestic reindeer of the Nenets and Evenki breeds, kept in various natural and climatic conditions of the tundra and northern taiga, during the calving and dairy periods. Experimental data were collected from clinically healthy animals. The research was carried out in accordance with the basic methods of zootechnical research (observation, examination). Their gender (visually) and age were determined (using ear tags and animal registration data, and, if necessary, based on the degree of tooth wear); An assessment of the exterior of the reindeer herd was carried out before the rut to select males and females for mating. Methods of visual assessment, linear measurements of animals, and field chronometry of calving were used.

Results. The Evenki breed of deer is distinguished by its large size, height, high load-carrying capacity and endurance when transporting goods and people. It has been established that the dynamics of calving of domestic reindeer of the Evenki breed is identical to the dynamics of calving of Nenets reindeer, but there are some peculiarities. In the tundra zone, calving takes 3—5 days longer, and the initial phase begins (on average) 7-10 days earlier than in the taiga zone. The live weight of Evenki breed calves at birth is 0.8 kg higher than that of Nenets breed calves. The intensity of growth up to 3 months of age is higher in the early, mass and late periods of calving. It has been established that calves of the early calving period exceed in live weight at birth and its growth the calves of the mass period, and those, in turn, exceed the calves of the late calving period. This pattern can be traced up to 6 months of age. Calves of early and mass calving periods, having the potential for rapid growth, find themselves in more favorable nutritional conditions in the first months of life than late calves. This is expressed in the ability to receive green pasture food 15-25 days earlier and be stronger by the time the blood-sucking dipterous insects appear. Early calving Nenets calves are more active at night, since there is still a lot of snow in the tundra zone during this period and the temperature sometimes drops below 0ºC.

Purpose: zootechnical characteristics of the developing lines of Yakut breed stallions in the breeding farm "Agricultural production cooperative "Tonor" of the Oymyakon ulus of Yakutia.

Materials and methods. The study of the exterior indicators of the stallions was carried out by taking body measurements according to the instructions of the All-Russian Research Institute of Horse Breeding. The use of genotypic assessment methods for animals along with classical zootechnical assessment methods for pedigree, productive traits (live weight and meat productivity of offspring, milk production, fertility of daughters) was supplemented by the use of the method of selecting offspring based on their adaptability to herd conditions.

Results. Long-term selection work in the breeding farm of the Oymyakon ulus is completed by the formation of six lines of outstanding Yakut breed stallions. In terms of live weight, both stallions and mares of the Oymyakon horse surpass stallions and mares of the Yana, Kolyma and indigenous types. Oymyakon stallions (n=20) weighed on average 483,7±3,55 kg, while stallions of the indigenous types weighed 446,3±4,75 kg (n=34), Kolyma types 449,1±3,42 kg (n=87) and Yana types 469,4±3,27 kg (n=128). Oymyakon horse mares (n=165) also surpassed mares of the indigenous type (401,6±2,00 kg (n=341)), Kolyma type (432,2±1,13 kg (n=1063) and Yang type (431,0±1,16 kg (n=881)) in average live weight of 453,8±2,19 kg. According to measurements of head, neck, chest, croup, occiput and withers, chest and croup width and their indices, Oymyakon horse stallions and mares are practically no different from indigenous type horses. The founder of the line with the most numerous followers is the outstanding stallion Kyurzhet, born in 1946. He came from local Yakut horses of the former Bolshevik collective farm. His line continues on the Tonor farm through his two descendants: his grandson Chalay, born in 1981, live weight 515 kg, and his great-grandson Tenkelekh, born in 1992, live weight 490 kg. The farm produced Kyurzhet's great-great-great-grandson Chalay and 6 great-great-great-great-grandchildren, and now produces 11 continuers of the line (3 great-great-great-great-grandchildren and 8 great-great-great-great-great-grandchildren), a total of 18 continuers of his line have been and are being produced.

The Holstein breed of cattle was registered in the Russian’s "State Register of Breeding Achievements Approved for Use" in 1993 (application № 9352682). By that time, its relative abundance was 0,7 %. Over the past 28 years, despite the continuing decline in the number of dairy cattle in the Russian Federation the share of the Holstein breed has grown to 34,7 %, while for the vast majority of other breeds and almost all domestic breeds This indicator has significantly decreased: for the Red Steppe breed to 2,7 % (3 times), Kholmogor breed to 4,4 % (almost 2 times), Simmental breed — to 4,5 % (4,8 times). The relative number of Black-and-White cattle from 1993 to 2010 increased from 45,8 to 57,9 %, over the next 11 years it decreased to 42,4 %.

During the study period (from 1993—2021), in our country there was not only a reduction in the number of dairy cattle but also the replacement of domestic breeds for Holstein cattle (Red Steppe, Kholmogor, Simmental and Black-and-White).

The results of studies convincingly testify:

   milk production of Holstein breed increased annually by 29,4—150,0 % higher than that observed in animals of domestic breeds;

   consumer demand for pedigree Holstein heifers and primiparous is constantly growing while for animals of domestic breeds is declining and in the last 11 years, the annual demand for breeding Holstein breed has increased by an average of 3,7 %;

    the overall assessment of the body type of Holstein first-calf cows increased by an average of 0,3 points annually and at the same time productivity increased by 206,7 kg per year;

    if the identified rates of improvement of Holstein cattle are maintained in the near future, by 2026, the milk productivity of pedigree cows of this breed can reach an average of at least 11,0 thousand kg in milk yield, the fat content in milk is 4,20 % and protein is 3,40 %.

Purpose: determination of the adsorbent toxin and antioxidant vitamin C on the digestibility and assimilation of nutrients in the composition of compound feed for broiler chickens with a tolerant level of aflatoxin B1.

Materials and methods. The objects of the study were broiler chickens of the KOBB-500 cross. When setting up the experiment, the duration of 42 days, 4 groups of 100 heads each were formed from day-old chickens according to the principle of analog groups. The experimental birds were fed complete compound feeds (CF) based on corn, sorghum and fodder beans. The samples of compound feeds have a high chemical composition and the presence of mycotoxins. Upper limits of permissible concentrations (ULC) for aflatoxin B1 were established in all three types of feed grain. Therefore, they were mixed with safe mycotoxin additives using dispensers in the feed shop of the poultry enterprise. In this way, tolerable levels (no more than 0,25 mg/kg of feed) of the content of this mycotoxin in the composition of the PK fed to the experimental birds were achieved. Against the background of the conducted scientific and production experiment with the use of chromium oxide in the composition of compound feed (as an inert indicator) on chickens (aged 35-42 days) of comparable groups (5 heads from each group), we conducted an exchange (physiological) experiment. Based on the results of chemical analysis of the fed compound feed and excrements in the droppings of the experimental birds, the level of digestibility and assimilation of nutrients in the diet was calculated.

Results. During the experiment, the leadership of the combined introduction of the adsorbent toxfin in the amount of 1500 g/t and ingredient C in the amount of 500 g/t of feed into complete feeds for broiler chickens with a tolerant level of aflatoxin B1 was established. As a result, compared to the birds of the control group, the chickens of the 3rd experimental group had significantly (р<0,05) higher coefficients of digestibility of dry matter by 3,66%, organic matter by 3,90 %, crude protein by 3,63 %, fiber by 3.06% and NFE by 3,19 %, respectively. In terms of the degree of nitrogen assimilation (60,45 %), the result (51.45 %) and phosphorus (49,67 %) from the generally accepted amount with feed, the best indicators were also obtained in broilers of the 3rd experimental group, which reliably (р<0,05) outperformed their control indicators for these indicators by 3,74 %, 2,91 % and 2,45 %, respectively.

Purpose: to study the effect of vitamin C and MEK Feedbest®VGPro when introduced into the compound feed of broiler chickens with excessive background of heavy metals on the indices of meat productivity, food and biological value, ecological safety of their meat.

Materials and methods. The objects of the study were meat chickens of the ROSS-508 cross. At the age of one day, 4 groups of 100 birds each were formed from them in accordance with the principle of analog groups. In the composition of the used recipes of complete compound feed in all three age periods of growing, the main grain and protein ingredients were represented by locally produced feed: corn, wheat, peas and rapeseed meal. Growing of experimental broilers for meat was completed at the age of 42 days and their control slaughter was carried out, for which 5 birds were selected from each group. The concentration of salts of heavy metals was determined in the samples of feed and meat of the experimental birds.

Results. The experiment substantiated the feasibility of combined introduction of MEC Feedbest®VGPro at a rate of 100 g/t of feed and vitamin C at a rate of 500 g/t of feed into diets with excessive content of heavy metal salts. Compared to the control analogues, broilers of the 3rd experimental group showed a reliable (p<0,05) decrease in fat by 0,26 % and a simultaneous increase in dry matter, protein and the value of the protein-quality indicator in the pectoral muscle samples. Combined additions of the tested preparations contributed to a decrease in the concentration of zinc by 63,17 % (p<0,05), cadmium by 61,11 % (p<0,05) and lead by 62,34 % (p<0,05) in poultry meat samples from the 3rd experimental group, compared to the control. Moreover, in the meat samples of broilers of the 3rd experimental group, the maximum permissible concentrations of none of these elements were exceeded.