Mammoth fauna found in the permafrost in Yakutia are usually well-preserved, with up to 90% of unique discoveries, including those with soft tissues and fossil animals with intact biological fluids. Despite the exceptional preservationconditions in the deep permafrost, the remains of woolly mammoth have not been used in paleoparasitological research. This article introduces the initial findings of a paleoparasitological investigation conducted on thawed samples obtained from a woolly mammoth. The research material consisted of the gastrointestinal contents of a woolly mammoth found in the Bulunsky district on the Bykovsky Peninsula in 2022. The mammoth’s remains were discovered in permafrost and were consistently frozen until sampling, maintaining their shape well. Traditional helminthological methods, such as native smear and the Fulleborn method, were used. For the first time, eggs and larvae of helminths from the Nematoda class, including the Ascaris eggs from the Ascaridata suborder, family Ascarididae Baird, 1853 were identified in frozen-thawed samples of the woolly mammoth. A total of 13 eggs were found, showcasing excellent preservation that allowed for visualization of eggs at various developmental stages and measurement of eggshell size and thickness. The diameter of the Ascaris eggs from the woolly mammoth (Mammutus primigenus (Blumenbach, 1799)) was 73.25 ± 1.47 microns, with a shell thickness of 4.10 ± 0.20 microns. Additionally, four varieties of whole larvae and larvae fragments of the Nemathelminthes type within the Nematoda class were identified for the first time. These discoveries contribute to our knowledge of ancient fossil animals parasites and require further exploration.

Thein terim results of the first year of the project,funded by theRussian Science Foundation(RSF), are presented. The study focuses on the species diversity of the symbiofauna of domestic animals bred in Yakutia.A total of 1,760 samples were collected from various types of domestic animals and analyzed. The research identified and described 98species of endobiontsin ruminantsand25species in horses (based on2breedtypesof theYakutbreed). Additionally, severalr are species of ciliates were discovered during the study. Notably, this study is the first to compare the diversity of Yakut aboriginal cattle with crossbred and Simmental cattle. The findings reveal that the endemic Yakut cow, bred under conditions of poor, low-nutrient feeding during along winter period, has developed an adaptive functional feature, such as a diverse symbiont fauna of protozoa, to facilitate the complete breakdown and absorption of limited nutrients in the feed. Furthermore, the study found no significant differences in symbiofauna between the Even and Chukotka reindeer breeds, which differ in their breeding zones.In the Even breed of deer, a total of 13 species were identified, while in the Chukchi deer, 11 species from six genera were found. In domestic sheep and hybrids (which are half domestic sheep and half wild bighorn sheep), 12 ciliate species were identified, buttheir diversity did not differ. In theYakuthorsebreed,15 species of endobiont ciliates were identified, of which 11 are indigenous and 14 are of the Yan type. This research provides the first data on the endobionts of herd horses of the Yanatype of the Yakutbreed. Thestudied populations of herd horses were characterized by are latively high level of end obiontdiversity. The species similarity between two populations of the Yakut horse breed, bred in different geographical zones, was demonstrated. This research has identified the symbiotic fauna of domestic animals and established a connection between the species composition of the symbiotic fauna and the habitat of the animals, including their social behavior.

The results of the analysis of genetic characteristics for 15 microsatellite loci of the modern population of Yakut cattle of the gene pool enterprise of the State Enterprise of the Republic of Sakha (Yakutia) “Yakut Cattle” are presented. Yakut aboriginal cattle, considered one of the unique local breeds in Russia, are represented by a small population. It is distinguished by exceptionally high frost resistance (down to –60 Cº), unpretentiousness to living conditions and tolerance to insufficient nutrition. A comparative assessment of the allele pool of Yakut cattle was carried out on subpopulations of 7 farms: “Sakkyryr” of the Eveno-Bytantaisky ulus, “Kylys” of the Gorny ulus, “Taastaakh” of the Namsky ulus, “Kullegi” of the Amginsky ulus, “Onkhoi” of the Verkhnevilyuysky ulus, “Akana” of the Nyurbinsky ulus and “ Symakh” Megino-Kangalassky ulus. In total, data on 898 heads of purebred Yakut cattle were analyzed. Based on the results of the analysis, it was established that in all 15 microsatellite loci of Yakut cattle, polymorphism of alleles is widespread from 3 to 10. The most polymorphic is the TGLA53 locus, which has 10 alleles, despite this the number of effective alleles in this locus is only 2.76. Allele 160 (0.534) occurs with the highest frequency at this locus, and 188 (0.009) with the lowest frequency. In loci BM1818, INRA023, the smallest number of alleles was found – 3. Of all the analyzed loci, allele 256 of the SPS115 locus is observed with the highest frequency with an occurrence frequency of 0.733. The rarest alleles occurred with a frequency of 0.002 and 0.004. On average, the number of alleles per locus of indigenous Yakut cattle was 5.91 ± 0.46, which indicates a fairly high consolidation of the population of local purebred Yakut cattle and the lowest genetic diversity of the existing population of local cattle compared to cultivated breeds. A total of 90 alleles were identified in the Yakut cattle population.

A unique project on the hybridization of domestic sheep with wild bighorn sheep of the Yakut subspecies (Ovis nivicola lydekkeri) was implemented under extreme conditions in Yakutia. Hybridization was performed to obtain new forms that combine productive indicators with specific adaptation qualities to harsh breeding conditions. Viable hybrids of both sexes were obtained via laparotomy during the artificial insemination of domestic sheep with frozenthawed epididymal male bighorn sheep. We compared the hybrids with domestic lambs. At birth, the hybrids had a live weight of 2.65±0.19 kg, which is 29 % less than that of domestic lambs. A difference in live weight was noted before reaching the age of 20–24 months; however, by 36 months, hybrid males outnumbered domestic rams of the same age. We found that in the early postnatal period, hybrids were satisfied with their mothers’ milk faster and more often, and their daytime sleep was short and shallow. The hybrids also showed a high degree of curiosity, jumping ability, caution, and clear imitation of the mothers’ behavior. In terms of growth and development, the hybrids were tall and narrow-bodied because of their high mobile activity, as well as differences in nutrition. The hybrid offspring differed in chromosome set from the parental forms, having a diploid set equal to 2n = 53, whereas the maternal form of the sheep had 2n = 54, and the paternal form had 2n = 52. The resulting hybrids are fertile, and differ from their peers in the dynamics of development, nutrition, and ethology. They have phenotypic features similar to those of the paternal form, and a new improved form of the genotype is the basis for selection in sheep breeding.

The currently observed climate change towards warming affects the expansion of the suitable range of new species of insects and microorganisms for the northern region, which, in turn, being carriers of many diseases, can increase the risk of invasion of domestic animals that have not previously been found in these areas of diseases. It is easy to assume that any climate change can affect the established way of life of the indigenous peoples of the North, the main life-supporting occupation for which is still traditional farming - breeding reindeer, cattle, including aboriginal, and herd horses, as well as hunting, fishing, picking berries and herbs. At the same time, northern animal husbandry occupies an important place in the economy, due to the characteristic way of life of the indigenous peoples of the North, especially northern reindeer husbandry. The trend of change in the indicator of the average annual temperature from 1961 to 2020 has been established in Yakutia towards warming in both central and northern regions. Such changes in the considered climatic indicators have a significant impact on the expansion of the distribution area of the ixodidae (hard ticks) to previously inaccessible northern territories. Since 2000, in the territory of the Republic of Sakha (Yakutia), there has been a gradual increase of tick attacks cases on people with the annual coverage of new regions, including the Arctic. Although Yakutia is not endemic for tick-borne encephalitis, there is concern about the annual growth and expansion of the geography of tick attacks on the northern territories - if cases were previously noted only in 3 southern regions, then at present - in 21 regions, including Verkhoyansk, which is part of the Arctic group of regions. The correlation between these indicators was = 0.584. In the situation under study, in 34.14% of the total variability, the increase in the number of registered cases of tick bites is explained by changes in the average annual air temperature in certain areas.

The spontaneous nature and unpredictability of the cycling of the reproductive system of cows and heifers of the Yakut breed against the background of a low level of feeding, the structure of the herd of different ages does not allow planning work on insemination of animals. In addition, one of the negative aspects that complicate the work of reproduction in the gene pool farm is the location of these farms in the immediate vicinity of settlements, where a considerable number of livestock of other breeds are kept in organized and private farms. This greatly complicates the planned mating in order to keep the gene pool clean. In this regard, it is necessary to develop methods for induced estrus and ovulation of cows and heifers in order to control the reproductive function of cows and heifers of the Yakut breed in certain periods. This will make it possible to plan early mating in a shorter time, so that by the beginning of the pasture season, the breeding stock of Yakut cattle will be pregnant. An analysis of the breeding period in the gene pool farm for Yakut cattle, carried out after hormonal stimulation of Yakut cows, showed that the duration of the service period was reduced and averaged 68 days. As a result of the application of the scheme developed by us, young cows 4-6 years old were covered with bulls, pregnancy occurred on average in 2.22 hunts, 9-11 years old - in 3.33 hunts, in cows 12 and older - in 2.2 hunts.

The phenetic approach is widely used to analyze different populations of animals on a number of indicators. Venetica currently considered as an area of population morphological studies, which is based on the discrete group vnutricinovialnoe manifestations of epigenetic variation leading to the realization of morphogenesis in the stable States of non - metric traits- phenes, and their compositions and relies on the feature extraction markers for the implementation of ontogenetic programs, which depends on a number of conditions. In relation to farm animals venatici methods have been little used, however, in cattle today allocated more than 40 hair dryers. One of the most promising directions in the study of fanatici cattle is the study of the diversity of dermatitov nasolabial mirror of cattle

One of hybridization objectives is to improve adaptive traits in domestic animals to certain conditions. When hybridizing, new livestock breeds including sheep were produced. Behavioral characteristics and habits are transferred from parents to the hybrids obtained. Herein, it is to be noted that wild species when crossed with domestic sheep can pass on not only beneficial, but also undesirable traits to offspring. The undesirable traits may be referred to as late maturity, poor technological qualities of wool, wildness, fearfulness and aggression. Therefore, to study behavioral responses of F1 hybrid lambs in the early postnatal period and reveal possible training with imprinting and individual experience of the animals’ impressions will allow to identify the hybrids’ ability to get accustomed to man, escape stress situations and reduce the number of injury cases caused by needless wildness or fear. Keeping the hybrid offspring under the conditions maximally close to wild forms’ natural dwelling and those of minimized contacting man make for animals show up undesirable behavioral forms, such as fearfulness, alertness and aggressiveness. The conditions maximally close to domestic sheep housing with hybrid biological characteristics considered were created for the hybrids: Besides, mountain landscape was simulated to support active mobility of the hybrids. Close and continuous contact between the hybrid offspring and man is the principle point to achieve the goal.

In work dynamics of change of biochemical parameters of peripheral blood of the house reindeer zoned in the Central zone of Yakutia which testify to presence of seasonal and territorial dependence is analysed.