Animal husbandry is one of the main agricultural industries in most countries over the world as well as in the Russian Federation, and its profitability is determined by three main factors: the animal genetic potential, complete diet and freedom from infectious, invasive and mass non-infectious diseases. One of the most significant and difficult tasks is to generate and rear healthy young cattle. Digestive disorders clinically manifested by diarrhea resulting in apparent dehydration, toxemia, enophthalmos, membrane pathology, immunodeficiency and metabolic disorders are prevalent among neonatal calf diseases in early postnatal period. Massive diarrhea in neonatal calves is characterized by significant polymorphism, involving a wide range of various factors including genetic, physiological, sanitary and hygienic as well as infectious factors. Infectious agents are the main causes of massive gastroenteritis in neonatal calves. In most cases viruses serve as triggers for gastrointestinal pathology development and bacteria play the secondary role. For a long time, rotaviruses, coronaviruses and pestiviruses have been believed to play the main role in etiology of massive neonatal calf diarrhea. In recent years, a number of new and understudied viruses, including kobuvirus, nebovirus, norovirus, torovirus and astrovirus, have been detected in fecal samples from diarrheic calves and their role in diarrhea development has not been definitively determined. Their role as primary pathogens, coinfection agents or commensals remains unclear. Recently these animal pathogens have widely spread in different countries of the world. At the end of the XX century – beginning of the XXI century, large numbers of cattle were imported to the Russian Federation, including cattle from the nebovirus-infected countries. Data on nebovirus infection (occurrence, pathogen characteristics, disease clinical signs and epizootological features) are given in the paper.

Colibacillosis is a bacterial disease of humans, animals and birds caused by Escherichia coli, pathogenic gram-negative bacillus. Despite its secondary nature, colibacillosis widely affects poultry farms and causes significant economic losses. The disease spread is closely associated with antibiotic resistance problem because a diseased carrier bird may be a reservoir of antibiotic-resistant Escherichia coli strains. In addition, genes of virulence and resistance have been proven to be transferred from avian Escherichia strains toextra intestinal pathogenic strains that are dangerous to humans. Colibacillosis is transmitted aerogenically, alimentally, rarely transovarially, with droppings, mucus, feed, water, handling tools and operating personnel. Birds are most susceptible attheage of1–14days and at the onset of laying period. The disease may present asacute, subacute and chronic forms and is most often manifested by catarrhal hemorrhagic enteritis with profuse foamy diarrhea, respiratory tract lesions, fibrinous peritonitis and polyserositis, as well as a significant decrease in weight gains, stunting, egg laying decrease or complete cessation. Colibacillosis is diagnosed comprehensively taking into account the epizootic situation, findings of clinical examination and postmortem examination of dead or emergency-slaughtered poultry as well as laboratory test and bioassay results. Bacteriological, serological and molecular genetic methods are used for the disease diagnosis. Colibacillosis prevention includes improvement of poultry keeping practice (control of feed and water quality, disinfection, pest control, microclimate control) as well as timely complex vaccination of all poultry. The disease shall be treated taking into account primary etiological factors and bacteria sensitivity to antimicrobials.

High pathogenicity avian influenza has a significant negative impact on poultry farming, international trade and health of wild bird populations, therefore the infection requires the utmost attention of the entire international community. The article investigates the evolutionary and epidemic processes observed in recent years in many countries of the world where avian influenza outbreaks occur; describes the ways of the infection spread; the prevalence of the virus types for the last several years, as well as the expansion of the host range, including among representatives of the Mammalia class. The change in the ratio between the virus types starting from 2020, when H5N8 subtype was responsible for the overwhelming number of the disease outbreaks reported, until 2022, when an obvious predominance of H5N1 subtype was detected is demonstrated. A noticeable expansion of the disease-affected areas in Central and South America, the influence of migration, anthropogenic and other factors on influenza spread are highlighted. The conditions facilitating the occurrence of the infection outbreaks affecting mammals, wild animals and livestock, zoo and companion animals are described. Cases of mammals’ infection on the North American and Eurasian continents in zoos, nature parks, backyards and fur farms, asa rule, coincide in time with the infection outbreaks in waterfowl populations. The WAHIS data were analyzed and the high ability of the virus to spillover from birds to mammals, such as martens (minks, otters, ferrets, badgers), cats (domestic cats, cougars, leopards, lynxes), pinnipeds (common seals, grey seals), bears (brown, grizzly, American black), bottlenose dolphins, skunks, foxes, opossums, raccoons was demonstrated. Changes in the habitats of both migratory birds and mammals, including due to some human economic activities, add an ecological and urban component to the complex task of the control and prevention of the epidemic, also posing a potential threat to humans.

Feline panleukopenia, a disease globally known since the beginning of the last century and originally attributed to canine distemper, has expanded its range of hosts since its discovery as a result of successful infections (both natural and experimental) in mustelids, raccoons and even primates. Evolutionarily, the disease pathogen gave rise to anew infectious agent– canine parvovirus, which, despite its DNA structure, demonstrates a relatively high mutation rate and the emergence of new variants. The disease is in most cases fatal to newborn kittens and causes severe manifestations in adult cats, severely affecting the vital systems of the body. The prognosis is often (up to50%) unfavorable, while the animal’s age plays a key role. Current preventive measures can ensure protection, however, vaccines are used in the absence of adequate testing on cats and dogs (for ethical reasons) and have a number of limitations in use. The persistence of the infectious agent in the environment and the growing number of stray animals allow the infectious agent to circulate unhindered in these populations, threatening the health of domestic cats and endangered felines in nature reserves and zoos. Easing of legislation for leading research centers, regulation of the number of stray animals, adequate prevention measures for target groups in animal shelters, nurseries and zoos can contribute to a significant reduction in the circulation insusceptible populations of pathogens not only of this disease, but also of the majority of other dangerous infections, such as rabies, feline rhinotracheitis, canine distemper and others.

Retrospective analysis of enzootic bovine leucosis (EBL) data received by the Republic of Dagestan Veterinary Laboratory and Veterinary Department of the Republic of Dagestan was made. From 1988 to 2022, the Republican veterinary laboratories serologically tested3,205,118 animal sera for the antibodies to bovine leukaemia virus (BLV) antigen, and 76,133 (2.4%) of them were positive. High BLV infection levels were detected in 1988 (32.2%), 1989 (21.3%), 1991 (23.3%), 1993 (23.0%), 2005 (24.2%), 2010 (23.0%), and the lowest ones were reported in the recent years: 2020 – 1.0%, 2021 – 1.0%, 2022 – 0.5%. In2022, diagnostic testing of 875,312 serum samples was carried out, which included 476,493 sera collected from bovines in high-altitude and mountainous areas of Dagestan. In the plain areas, 255,312 bovine animals were tested for leucosis, and 122,967 animals were tested in the sub-mountain areas. The animal infection with BLV in these natural and climatic conditions was reported as follows: high-altitude and mountainous areas– 0.5% (2,313 animals), plain areas– 0.8% (1,925 animals), sub-mountain areas– 0.1% (109 animals). Additional 20,540 serum samples were tested in the laboratories at the transhumance pasture veterinary units, and 170 BLV seropositive animals (0.83%) were detected. No EBL was diagnosed in the laboratories of the Derbent, Kochubeysk, Ulankholsk, Bakressk veterinary units, but other four laboratories detected high level of BLV seropositive animals (Kizlyarsk– 14.6%, Babayurt – 3.6%, Tarumovsk– 3.0%, Kyzylyurt– 1.06%). Thus, EBL is widespread in animals, especially in the plain areas of the Republic of Dagestan.

Studying the agents of bovine viral diarrhea (BVD) is an important task given the high probability of new isolate introduction into the Russian Federation, as well as the need to take into account the genotype and subgenotype of the virus circulating in a herd when developing vaccines and diagnostic kits for the infection. During the work performed, 6 BVD virus isolates were recovered and identified. The recovery of these isolates in the lamb testicle cell subculture revealed that Bashkiria/2019, Kirov/2020 and Samara/2020 isolates belong to non-cytopathic bovine viral diarrhea virus biotypes, Chelyabinsk/2021 isolate demonstrated the characteristic cytopathic effect in the monolayer and was classified as a cytopathic variant of thevirus, the adaptation of Belgorod/2021 and Udmurtiya/2020 isolates to this cell system was not possible. The study also identified the species of the recovered isolates. Based on the analysis of the nucleotide sequence of genome 5’-untranslated region (5’-UTR) fragment, these isolates were classified as belonging to three genotypes of the virus. The phylogenetic analysis showed that Chelyabinsk/2021 and Udmurtiya/2020 isolates belong togenotype2 and demonstrate, respectively, 98% and99% homology with reference 890 strain of BVD virus. The recovered Bashkiria/2019, Samara/2020, Kirov/2020 isolates were classified as belonging to subtypes 1i, 1f and1b ofgenotype1, and Belgorod/2021 solate represents genotype 3 of the virus. The findings from the study confirm the presence of all three genotypes of bovine viral diarrhea virus in the Russian Federation and reiterate the need for the development of specific prevention and diagnosis tools for the disease.

Cow’s milk quality, which may deteriorate due to inflammatory processes in the mammary glands, remains one of the important problems of dairy farming and requires effective, safe and affordable therapeutic agents. Nanocomposite silicon-zinc-boron-containing glycerohydrogel (Si-Zn-B-gel) may become a very good solution to the issue. The paper demonstrates wound-healing effect of the glycerohydrogel and confirms its effectiveness for teat hyperkeratosis treatment indairy cows. Results of a rat burn model – based experiment suggest that Si-Zn-B-gel is a promising wound healing agent for topical use. Thus, on Day 9 complete re-epithelialization of the burn surface was observed, with fibrous structures prevailing in the granulation tissue of the dermal layer, on Day 19 a mature scar was formed with a longitudinal alignment of collagen fibers. The production tests conducted inhigh producing dairy cows have demonstrated good therapeutic effect of the Si-Zn-B gel for teat-end hyperkeratosis and confirmed its long-term effect that helps to longer maintain the results achieved during treatment. After a 7-day treatment physiological structure of up to 27.8% teats improved, on Day 14 of the experiment no severe hyperkeratotic lesions were observed and the number of teats that correspond to the physiological norm was 72.2%. Analysis of the data collected shows that the Si-Zn-B-gel is effective for teat-end hyperkeratosis treatment, thus, it prevents mastitis in animals and improves the milk quality.

According to the World Organisation for Animal Health, foot-and-mouth disease (FMD) is regularly reported in domestic and wild cloven-hoofed animals in Africa. G-I, G-IV, G-VI, G-VII, ASIA/Iran-05 genetic lineages of serotype А FMD virus are considered to be the most widespread on the African continent. Given the close economic and trade relations maintained by the Russian Federation with the countries of North Africa, of particular interest for us is studying the FMD virus of serotype A G-IV genetic lineage, which has been responsible for the infection outbreaks in the naturally susceptible animal population of the said region every year since 2012, and there is a risk of introduction of this virus genotype in to the Russian Federation. Therefore, the issues of FMD introduction risk assessment and timely diagnosis are relevant for the Veterinary Service of Russia. FMD virus A 2205/G-IV strain tested for its biological and antigenic properties in cell cultures and naturally susceptible animals (cattle and pigs) was adapted for its reproduction in initially trypsinized porcine kidney (PK) cell culture, continuous monolayer cell cultures (IB-RS-2, PSGK-30, YaDK-04, ВНК-21) by five serial passages. The virus was considered to be adapted when 90–95% cytopathic effect developed within 14–19 hours after the cell culture infection. The virus adapted to the cell cultures was tested for its infectivity with microtitration in IB-RS-2 cell culture. The virus strain tested for vaccine matching with microneutralization test (MNT) demonstrated significant difference from production A/Turkey/06, А22 No. 550/Azerbaijan/64, A22/Iraq/64, A/Iran/97, A No. 2155/Zabaikalsky/2013, A No. 2166/Krasnodarsky/2013, A No. 2269/ARRIAH/2015 strains of FMD virus.

In 2012–2021, 2,030 outbreaks of acute infectious animal diseases were registered in the Republic of Kazakhstan. Among all the diseases blackleg accounted for 20.7% (421 outbreaks), which suggests that the nosological unit is of high epizootological significance among other infectious animal diseases in the country. Analysis of the blackleg outbreaks registered over the recent 10years demonstrates asignificant annual growth in the number of outbreaks (from19 to 81outbreaks) in the Republic of Kazakhstan and the disease persistence in the territory. Within the mentioned period, the average number of blackleg-infected animals per one outbreak ranged between1 and 3 animals, which proves that blackleg is anon-contagious disease. The research indicates that blackleg is a seasonal disease in the Republic of Kazakhstan with an incidence rise in autumn. The data analysis for 2012–2022 did not reveal any regular blackleg epizooties. The epizootological zoning made it possible to conclude that the blackleg situation in 6 Oblasts (which account for42.8% of the total territory) was rather tense; in 5 Oblasts (35.7% of the country’s territory) the epizootic situation was less tense and the remaining 3 Oblasts (21.5%) are disease-free. Therefore, blackleg zoning in the Republic makes it possible to use a differential approach to planning preventive veterinary and control measures, depending on the intensity of the epizootic situation. The research results will help to improve the system of blackleg surveillance, to predict the disease spread in animals and can be used to develop anti-epizootic measures.

Ability of the continuous cell lines to evolve enables generation of new transformed cell cultures with unlimited life potential and different from the original prototypes in the process of sequential cultivation. There are practically no universal mechanisms and methods for new cell line generation. But it was noted that cell immortalization is associated with chromosomal rearrangements (chromatid morphology) and changes in the number of chromosomes. The paper presents the results of the generation of a new Testis Capra hircus(TCh) cell line, suitable for effective replication of dermatotropic and other types of animal viruses, in order to scale up viral material used for the manufacture of the means for animal disease specific prevention and diagnosis. The monolayer TCh cell line was transformed from the continuous YаDK-04 cell line as a result of more than 50 passages in the growth medium supplemented with 10% of lanthanide-treated bovine serum. Use of the bovine serum purified and supplemented with lanthanides during the cultivation of the continuous cell line YаDK-04 led to significant chromosomal rearrangements and contributed to the formation of a stable and productive new TCh cell line, which differed in cytomorphological and karyological characteristics and had unlimited potential for passaging without changing the cell karyotype and morphology. The novel continuous cell line proved to be suitable for effective reproduction of such disease pathogens as lumpy skin disease, sheep pox, peste des petits ruminants agents. These are mainly viruses of dermatotropic origin.

Mesenchymal stem cells (MSCs) have been known to mankind since the mid-20^th century. The comprehensive study revealed their high biologically active potential. Capacity of forming several types of body tissues was demonstrated. The stem cells, like any other cells, exert their effect on surrounding cells and tissues by secreting extracellular vesicles. The extracellular vesicles of the stem cells possess biological activity of parent cells. Taking into account the regenerative potential of the mesenchymal stem cells, they are currently used in medicine, and also in veterinary medicine for treatment of various injuries of the companion animals. Effect of the mesenchymal stem cells on boar and rat sperm cells during 12-hour storage was studied. The study results demonstrated that during 12 hours of coincubation, the porcine MSCs contributed to the survival of the boar sperm cells and maintenance of their motility at 60–80% (depending on the solvent) as compared to the controls. Such a significant effect was not however observed during coincubation of the rat sperm cells with rat MSCs. But it should be noted that before the3^rdhour of coincubation, the experimental sperm motility was higher than that of the control. By hour5 of the observation, this difference was leveled. The rat and boar sperm cells are likely to have different physiological characteristics, which were reflected in the results obtained. Therefore, possibility of using the MSCs for the storage and cryopreservation of the semen of some animals was demonstrated, but this requires further research.

Being the primary link in the disease notification system, specialists of the veterinary service in livestock holdings ensure continuous monitoring and control of animal health. This analysis includes assessment of the actual availability of veterinary services in the absolute majority of animal holdings in 85 Subjects of the Russian Federation. In total, the study covered 6,226,368 holdings for major livestock species, such as cattle and small ruminants, pigs, poultry, horses and fur animals. Small-scale holdings have been shown to account for the largest proportion (99.7%) of the total number of livestock farms, while the proportion of holdings where animal health control is daily organized has varied from 0.03% in fur farms to 3% in poultry farms. The significant role of animal owners in small-scale holdings within the implementation of epizootological surveillance has been determined. It was revealed that the main populations of pigs, poultry and fur animals are concentrated in large-scale livestock farms. The study results indicate a relatively favorable situation in pig and poultry holdings, where only single cases of lack of veterinary service were reported. On the contrary there are multiple cases of lack of veterinary care in the farms for rearing cattle, small ruminants, fur animals. The paper highlights the mechanisms for the implementation of tasks assigned to the state veterinary service in terms of the organization of planned preventive and diagnostic veterinary measures in large pig breeding establishments. Proposals were made to introduce a legally fixed obligation for animal owners in large-scale livestock holdings to establish and maintain the production veterinary service, as well as a proposal to establish divisions of the state veterinary service in large-scale livestock establishments.