Production and cryopreservation of somatic cells (SCs) from valuable and endangered animals allows a preservation of genetic diversity and ensuring their future reproduction. The aim of present work was to isolate SCs from the ear of unique hybrid sheep (Ovis aries) and snow sheep (Ovis nivicola borealis) post-mortem. In this purpose, enzymatic and mechanical methods of tissue preparation were compared.

Materials and Methods. Ears from deceased animal were brought to the laboratory 12 hours after the death in a pasture, and biological material was thoroughly washed under running water. The hairs were removed from the part of the ear shell by the blade. Skin fragments were treated with 70% ethyl alcohol, washed three times in a saline solution with antibiotics and ground up to small pieces. The ear pieces were washed several times in phosphate buffer saline and divided into two parts. One part of the explants started in vitro culture without enzymatic treatment (group 1), whereas another part was pre-treated with a 0.25% trypsin/EDTA solution. After trypsinization, either tissue fragments (group 2), or cell complexes separated from cell suspension fraction (group 3) were taken for in vitro culture for 9 days. Monitoring of cell colony formation and growth was carried out daily.

Results. In the group 3, cell colonies were formed on the second day of in vitro culture. In groups 1 and 2, cell growth was observed from tissue fragments after five days regardless of the treatment. On the 9th day, all the groups produced the primary cultures, represented by two types of SCs. In general, single cell complexes from the group 3 formed cell growth zones more quickly than tissue explants from the groups 1 and 2, however, final cultures of SCs and their morphological aspects were no different between the groups.

Conclusion. Methodological protocols were proposed and successfully used to obtain in vitro cultures of SCs from the ear of dead sheep/snow sheep hybrid animal, 12 hours post-mortem that may allow further storage of valuable genetic material.

Infusoria from the digestive tract of herbivorous mammals have been known to science for almost a century and a half. However, protozoans remain an understudied group of rumen dwellers in ruminants. In cattle, in a multi-chambered stomach, in addition to microorganisms (fungi and bacteria), there are a large number of protozoa (infusoria), which also participate in the digestive processes that support the vital activity of the body. Endobiontic infusoria take an active part in the digestion of complex carbohydrates, fiber, in the breakdown of indigestible polysaccharides, which are essential sources of energy for animals. In this regard, the study of the species and quantitative composition of the infusoria fauna of cattle bred in the Far North, as one of the factors of sustainable adaptation to extreme conditions, is of great scientific and practical interest.

This article presents the results of a study of endobiontic infusoria of cattle breeds bred in Yakutia. A total of 36 species have been identified and described in 12 genera and 3 families. It was found that the genus Entodinium and the genus Isotricha were the most represented in the Yakut cattle, while the genus Entodinium and Euplodiniumin are in the crossbred and cultivated cattle. The smallest genus in all groups are Polyplastron and Metadinium.

The aim of the study is to assess the breeding value of the breeding stock of Ayrshire cattle from 13 breeding farms in various regions of the Russian Federation using the BLUP Animal Model method.

Materials and methods. The analyzed sample included data on 14,450 cows with a first calving date of 1987 – 2021, which were analyzed for identification errors and discrepancies in the dates of birth of parents and offspring. The forecast of the breeding value of cows based on milk productivity traits for 1 lactation was made using the best linear unbiased forecast method BLUP Animal Model using the RStudio program.

Results. The dynamics of milk yield EBV values during the studied time period with different numbers of first calving cows was studied. EBV estimates varied not only depending on the level of absolute milk yield of first-calving cows, but also under the influence of factors such as reproduction, the number of herds being assessed, as well as management, by which herds differed.

Conclusion. The assessment of breeding value using the BLUP AM method made it possible to reliably evaluate the studied array of animals of the Ayrshire breed breeding stock on farms in the Russian Federation. The best and worst producers in terms of milk yield were identified, taking into account the effects of various factors.

Purpose: to study the species diversity of the endobiontic fauna of the domestic reindeer of the Even and Chukchi breeds.

Materials and research methods. There were studied the stomach contents of 69 adult reindeer of two breeds: the Chukchi breed from the Nizhnekolymsky region (40 heads) and the Even breed from the Oymyakonsky region (29 heads). The collection of the proventriculus contents was carried out during the mass slaughter of domestic reindeer in November 2022. The time interval after the slaughter of the deer before sampling was no more than 20-25 minutes. Samples were fixed with 10% formalin solution. The identification of species was carried out according to the determinants of Dogel V.A., 1929; Kornilova O.A., 2003, 2010. Species composition comparison of the endobiont infusoria of the animal fauna of the studied breeds was carried out according to the Jacquard-Malyshev similarity coefficient (Kj-m) and the Czekanowski-Sjørensen fauna commonality index (Ics).

Results. As a result of the research, it was established that the species diversity of the endobiontic fauna of domestic reindeer of the Chukchi and Even breeds is insignificant, but differs. The species composition of endobiontic infusoria was determined on the basis of morphological and morphometric studies. In total, 18 species of infusoria belonging to 9 genera were identified, including 18 species of deer of the Even breed in 9 genera and 13 species of deer of the Chukchi breed in 6 genera. The basis of common species of infusoria for deer of the Chukchi and Even breeds bred in Yakutia is 3 species of Entodinium, 3 species of Epidinium, 2 species of Diplodinium and Ostracodinium, 1 species of Polyplastron, Enoploplastron and Dasytricha. The greater species diversity of endobionts of the Even breed can be explained by the fact that the Even breed belongs to the taiga type with a wider variety of food plants eaten than in the tundra deer of the Chukchi breed.

Purpose: the study of biometric data on live weight and their significance for artificial selection in the population of the northern deer (Rangifertarandus L.) ..

Materials and methods. Information was used from annual reports of reindeer herding of the North of the Far East. The methods of variation statistics that are generally accepted in zootechnical research were applied. Extreme (LIM) and average values (M) of the sign, trust boundaries of the general average (M ± t ∙ m), the average square deviation (σ), the coefficient of variation (CV), the boundaries of the extreme class variation (M ± 2σ) are determined. Associations of a live mass of sexual age groups in the population of the northern deer were established by calculating the correlation coefficients (R) and rectilinear regression (B).

Results. The consolidated correlation coefficient (RSV), reflecting the level of direct linear connection of the live weight of calves with a mass of uterus and manufacturers, was ≈ 0.7, which relates to the degree of close dependence. Using the regression equation (y = a+bx) calculated the predicted average size of the live weight of young animals in the average live weight of the importance. The data allow you to establish the threshold of selection of tribal animals in order to obtain offspring with a given value of the sign. In the study, the impact on the live mass of the season, year, range, and farms is leveled. It was established that throughout the generations a living mass is a stable phenotypic sign. Biometric data on live weight, as a quantitative attitude, indirectly reflect the state and movement of group genetic information in the populations of deer of the Far North-East of Russia.

Purpose: to determine the influence of the mass of hatching eggs on the growth and development of hatched chickens and on the quality of the eggs obtained from them in hens of the Pushkin breed.

Materials and methods. The material for the study was chickens of the Pushkin breed, in the amount of 70 heads. 52 weeks of age and their descendants, used later in reproduction (85 ♀ and 28 ♂). The birds were kept in individual cages. Conditions of keeping and feeding are in accordance with the standards adopted in the bioresource collection of the All-Russian Scientific Research Institute of Growing Animals “Genetic collection of rare and endangered breeds of chickens”. Immediately before incubation, 340 eggs were estimated by mass. hatching eggs. The hatched chickens were weighed at the ages of 2, 4, 6, 8, 10, 12 weeks. Depending on the weight of the incubation egg of the mothers and the sex of the chick, the data obtained were divided into three groups: Group I (light) ⩽M-0.5σ (⩽63.7 g-♀ and ⩽65.14 g-♂), Group III ( heavy) ⩾M+0.5σ (⩾68.2 g-♀and ⩾70.07 g-♂), eggs with intermediate weight are classified as “medium” - group II. At the age of 35 weeks, eggs obtained from daughters of the experimental groups were assessed.

Results. It was noted that there are high correlation coefficients between  weight incubation eggs the weight day-old of chickens: for hens r = 0.85 for roosters 0.95 (Р<0,001). The average live weight at one day of age by group differed significantly from each other. Significant differences were observed in both hens and roosters between groups I and III at 2 (P<0.05), 6, 8, 10, and 12 months of age (P<0.01). There were no significant differences in live weight between groups I-II and II-III. In terms of the quality of daughters' eggs, significant differences were observed in the weight of laid eggs between groups I and II, I and III (P < 0.01). In terms of the mass of protein, yolk, shell and the energy value of eggs, the highest indicators were noted in group III.

Conclusion. Studies have shown that the weight of eggs affects not only the live weight of chickens at the daily age, but also the live weight at a later period of growth. The coefficient of heritability of eggs mass (h2) for mothers was 0.701 (P<0.001) and for fathers 0.389 (P<0.01). Thus, it is possible to increase meat productivity without reducing the quality of eggs in meat-egg breeds of chickens by selecting incubation eggs of a larger mass.

The purpose of the work is to to systematize scientific data on factors affecting sperm fertility. Sperm fertility is the ability of a sexually mature organism to reproduce offspring. It is determined by parameters such as sperm motility and the quantity of normal and pathological sperm forms in the ejaculate. The fertility of male producers is acquired in stages: spermatogenesis occurs at the beginning, then the spermatozoa mature in the epididymis. The epididymis plays a significant role in making sperm fertile. Maturation occurs due to a complex of substances produced by the epididymis, and the full maturation of spermatozoa occurs in the genital tract of the female. Thus, fructose, produced by the vesicular glands, affects the fertility of animals. Another substance found in seminal plasma is citric acid, which takes part in the acrosomal reaction. Fertility is influenced by such factors as: the age of the animal, breed, the health of the male's reproductive system, heat stress and others. For instance, as animals age, the number of pathological sperm forms increases in the ejaculate, and their motility decreases. The same happens in cases of inflammatory diseases of the male reproductive system. Changes in the qualitative characteristics of sperm were recorded among Simmental and red breeds, as well as Holstein-Frisian and Jersey breeds. Prolonged or severe heat stress can also have a negative impact on fertility, despite the presence of compensatory mechanisms. These mechanisms are maintained by the presence of sweat glands in the scrotum, which are innervated by sympathetic nerves, as well as a reflex arc between the scrotum and the respiratory center. When the scrotum's temperature rises, respiratory rate increases, facilitating cooling. Furthermore, sperm activity can vary depending on the season. In animals with seasonal reproductive activity, sperm fertility parameters are better during the breeding season.

In summary, sperm fertility is a multifactorial process, the success of which is mainly due to the health of the male reproductive system and the presence of many compensatory and adaptive mechanisms.

Purpose: to study the effect of the duration of the use of progesterone for synchronization of the sexual cycle and the elaboration of the Dorper breed in the reproduction season.

Materials and methods. The object of the study was bright (n = 43) of the Dorper breed. Yarok was synchronized by the introduction of pessaries with progesterone (sidr) and injection on the day of removal of the CIDR of a chorionic gonadotropin of horses (HCH) in a dosage of 500 ME. Sheep were divided into three groups: I group (n = 13) – for 9 days a CIDR with progesterone (CIDR® OVIS, Zoetis, Madrid, Spain) was introduced for 9 days; Group II (n = 9) – CIDR was introduced for 11 days; Group III (n = 21) – CIDR was introduced for 13 days. In all three groups on the day of removal of the pessary, intramuscular injection of the HCL 500 IU is made. Upon completion of synchronization, observations of the signs of estrus were observed within 72 hours. Jacket was judged by the beginning of the estrus, when the state of immobility and the allowance of the ram of the ram was recorded. The duration of estrus was measured from the moment of the first intercourse until the sheep began to reject the male.

Results. The average interval between the removal of the pessary and the beginning of estrus in three groups was: in the first group – 38,7±5,1 hours; in the second group – 34,6±5,8 hours; In the third group – 52,4±4,4 hours. The minimum time from the extraction of CIDR to the beginning of the estrus was installed in the first group – after 12 hours, the maximum time was recorded in the third group – 96 hours.

Conclusion. The reliable effect of progesterone containing a gestagen drug on the reproductive indicators of the fierce, mainly at the beginning of the estrus, has been demonstrated. The most optimal is the use of CIDR with a constant rate of progesterone release by 9-11 days, since these groups have a 100% reaction to hormonal treatment.

Purpose: to conduct a comparative characterization of females matured for the first time at the age of 4 and 5 years according to the main mass-dimensional and reproductive characteristics.

Materials and methods. Experimental studies were carried on the basis of the Federal Fish Breeding Genetic Center (FSGTSR). The object of the study was female Ladoga char (Salvelinu salpinus L.) of the III generation, which reached puberty at 4- (n=50) and 5-year-olds. (n=45) age. Females of the second generation of factory breeding were individually assessed in two stages: during the first spawning at the age of five years (2019) and in the next spawning season at the age of six years (2020). When measuring the body and collecting genital products, clove oil was used as an anesthetic. Anesthesia was performed by placing the fish in an aqueous solution of clove oil at a concentration of 0,15–0,2 ml/l for 2–3 minutes.

Results. When evaluating mature females at the age of 4 and 5 years, it was found that with a statistically significant increase in body weight of five-year-olds from 1869.3 ± 57.5 to 2156.6 ± 96.53, the multiplicity between the body weight limits did not change with age and is 3 ,2. For other criteria, there is a tendency to decrease in variability. A statistically significant increase in the average weight of one egg is observed, provided that the average values of other reproductive traits do not differ. At the same time, the variability of these signs in five-year-olds is higher than in four-year-olds. So the working fertility increased from 37,4 to 55,1 %, and relative from 26,8 to 43,7 %. Correlation analysis showed the appearance of a weak negative relationship with age between relative fecundity and most of the weight-size traits, otherwise the general trends were preserved in conjunction with an increase in positive correlation.

Purpose: to study the accumulated data on the genetic determinism of the Kostyak fortress and discuss the possibility of their use to improve poultry farming.

In both meat-type and egg-type poultry, bone strength is an important characteristic of animal welfare, on which largely depends the economic efficiency. The lack of strength is expressed by bone fragility, deformations or fractures occurring both at certain technologies of animal housing and at processing of poultry products, which is accompanied by economic losses. The quality and strength of bone tissue is formed, in addition to housing conditions, by a complex set of interactions of structural, physiological, nutritional and architectural components. The study of poultry bone strength is also complicated by reproduction peculiarities. Egg laying determines some features of osteogenesis, including medullary bone formation, which deposit calcium for eggshell formation. To date, the actual assessment of bone strength occurs postmortem, by measuring bone mineral density and breaking strength. Both methods do not allow using the evaluated animals in breeding to improve bone strength, therefore the study of genetic determinants of this trait is a relevant research task. The use of modern information analysis based on DNA technologies is a necessary step for identification of candidate genes controlling bone strength, because of their ability to increase selection efficiency in poultry. This review discusses the available results of genome-wide association studies (GWAS) for bone strength in birds, as well as existing data on the relationship of bone strength with traits such as egg production and age at first lay.

Purpose: to study the segmentation of organometric and immuno-biochemical digital indicators in ewes with ESO at the end of gestation.

Materials and methods. The experiment involved three flocks of Tsygai, Volgograd and Stavropol breeds, each with 700 suyag sheep. Placental tissue samples were taken from clinically healthy and sick pregnant ewes, which were placed in 10% neutral formalin. Using a Cytadel 2000 histoprocessor (Shendon), the obtained samples were clarified in chloroform and enclosed in a Histomix paraffin medium (Biovitrum). Histosections were prepared on a rotary microtome (MICROM HM340E). Using the AxioScope.A1 (ZEISS) microscope, histopreparations were photographed and processed using the ZENpro 2012 (ZEISS) program. According to Schmidt and Thannhauser, the RNA content was determined using a two-wave spectrophotometer in UV. The activity of the G-6-Phase was studied by Swanson. In vacuum tubes Vacuette ™ (Austria), blood samples were taken in the morning before feeding, from the jugular vein.

Results. In sheep with eclampsia, a decrease in the total mass of the placenta, its cotiledons, as well as an increase in the length of the umbilical cord, in which stroma sclerosis is noted in the vascular wall, was observed. Small calcification foci were found in the tissues of the afterbirth, and small terminal villi are located around the stem villi near the vascular membrane, tightly adjacent to them. The proportion of syncytiotrophoblast of crypts of carbuncles and villi of the chorion of cotyledons of mature syncytium decreases in comparison with physiologically occurring severity. The content of RNA in its subcellular fractions is mainly concentrated in the microsomal fraction, 18% - in mitochondria and 7% - in the nuclear fraction. Albumins in pregnant ewes with eclampsia were reduced by 1.35 times. BASC and phagocytic activity of leukocytes in queens with eclampsia of pregnant sheep is reduced 15 days before lambing, which poses a threat to the reproductive health of the mother and the viability of newborn lambs.

Purpose: study and comparison of protocols for cryopreservation of sperm of stud rams.

Every day the popularity of sheep farming in Russia is increasing, since sheep are unpretentious in maintenance and at the same time they are multiproduct animals, providing the population with the necessary raw materials (wool, felt) and food products (meat, milk). For this reason, artificial insemination is of fundamental importance in the development of this branch of livestock farming, an important part of which is the correct cryopreservation of ram sperm. There are quite a few advantages of using cryopreserved sperm. Cryopreservation of sheep sperm contributes to the spread of the use of artificial insemination in this branch of the livestock industry. Freezing technology largely ensures the preservation of genetic material and its transportation, eliminating geographical barriers in the use of artificial insemination, and allows increasing the load on the ram sire without risk to his reproductive health. However, during the process of cryopreservation, sheep sperm receives irreversible damage due to cold shock, osmotic stress and oxidative processes, which lead to a decrease in the ability to fertilize sperm. Thus, chromatin may be damaged, membrane permeability increased, hyperoxidation and the formation of reactive oxygen species are possible, which affects the ability to fertilize. As a result, frozen ram semen may have low fertility. For this reason, it is extremely important to select an up-to-date freezing and thawing protocol with maximum recovery of viable and functional sperm of a given animal species for successful further use in artificial insemination. Technological advances in various fields of biotechnology have led to improvements in protocols, methods and equipment used in the laboratory, which have a positive impact on the reliability, accuracy of the procedure. This article summarizes research on the effects of different cryopreservation procedures, cooling rates, cooling times and thawing protocols on ram semen quality. In addition, a correct protocol for cryopreservation of Romanov breed sperm was formed, based on the results of our own research.

Natural amino acids being a part of food protein are known to be divided into essential and non-essential; essential ones if they are not present in food cannot be synthesized. There are two amino acids, threonine and histidine, which up to the present time have been a mystery for the biochemical science. However, it is universally recognized that threonine can be referred to as an essential amino acid as its absence from the food of all vertebrates results in the negative nitrogen balance. That is why specific features of threonine transformation with reference to different kinds of animals are not dealt with in the present paper. At the same time it was as far back as the thirties of the XX century that the fact of histidine being an essential amino acid for rats, mice, dogs and chickens but non-essential for men was proved. On the basis of the histidine essentiality thesis, a steady viewpoint that every living thing is not capabale of histidine synthesis was formed. But in this case the question arises: in what way has histidine become a non-essential amino acid for a healthy adult whereas for children and patients suffering from nephritic problems it has remained an essential amino acid? In view of the above different theories were put forward: 1) histidine reserves in haemoglobin and carnisone; the latter is enough with reference to adults but insufficient with reference to children; 2) histidine synthesis is caused by intestinal bacteria. But except mice whose muscles do not contain carnosine, the latter is a source of histidine for rats and dogs, histidine being an essential amino acid. It is only in the XXI century that the discovery of histidinol dehydrogenase enzyme  has allowed to answer the question. Histidine essentiality / non-essentiality as well as any other amino acid should be taken into account when making up rations for people and agricultural animal.

Purpose: Study red blood parameters in a group of cats with enterocolitis of unknown etiology using standard hematological research methods.

Materials and methods. During the study, standard methods of hematological analysis were used: erythrocyte counting was performed in a Goryaev chamber using whole blood diluted with isotonic sodium chloride solution 200 times, counting was carried out using a light-optical microscope Miromed-2 var. 3-20 inf. lens x8, eyepiece x10; the amount of hemoglobin was determined by the colorimetric method, diluting whole blood 200 times with a solution of 0,04 % ammonia on a Microlab-540 device; hematocrit value was determined by centrifugation using a Vilitek DSC-100MH-2 hematocrit centrifuge; the reaction to the erythrocyte sedimentation rate was performed in Panchenkov pipettes; erythrocyte indices and blood color index were calculated using generally accepted formulas.

Results. Thanks to the data obtained, we concluded that disruption of enzymatic processes, deterioration of absorption in the intestine and imbalance of symbiont microflora caused by enterocolitis can lead to the development of anemic conditions, manifested by changes in red blood parameters.

Purpose: Study of the fauna of endobiontic infusoria according to the types of the Yakut breed of herd horses.

Materials and methods. There were studied infusorian fauna of the intestines of the Yansky type horses of the Yakut breed from the Abyisky region (Arctic zone) and horses of the indigenous type from the Amginsky region and the suburbs of Yakutsk (the central zone). The material was collected during the mass slaughter of horses in November-December 2022, directly from the large intestine. The time interval after the slaughter of the horse before sampling was no more than 20-25 minutes. Samples were fixed with 10% formalin solution. The identification of species was carried out according to the guides of Strelkov A. A., 1939 [1] and Kornilova O. A. [2, 3]. Comparison of the species composition of endobiont infusoria of the cattle fauna of the studied breeds was carried out according to the Jacquard-Malyshev similarity coefficient (Kj-m) and the Czekanowski-Sjørensen fauna commonality index (Ics).

Results. There has been determined species composition of endobiont infusoria of the Yansky and indigenous type of the Yakut herd horse breed, bred in areas that differ in geographical location in the Arctic and central zones of Yakutia. A total of 15 species of infusoria have been identified. The percentage of occurrence by species ranged from 2,63 % to 13,2 %. The most frequently encountered species were Cycloposthium edentatum, Holophryoides macrotricha, Bundleia elongata, while Cycloposthium dentiferum, Spirodinium confusum, Cycloposthium ponomarevi and Allantosoma intestinale were rare.