Breeding Enterprises Research Articles

Indicators of zootechnical evaluation of fur coat and meat type sheep

Nowadays, due to the current economic situation in the Republic, the sheep breeding of Belarus is developing intensively, since there is a need for mutton in the global market. In some regions, work is already underway to create a promising herd of sheep with high meat productivity. An obligatory element of breeding activities is the evaluation of stud rams for the quality of the progeny, the accuracy of which determines the effectiveness of the selection process. The article contains the results on the development of zootechnical rules for evaluation of selection traits of the Romanov breed sheep that was conducted at the RUE “Vitebsk breeding enterprise”. The object of research was purebred Romanov breed animals that had been used in pedigree breeding since 2017. As a result of research, parameters for sheep ranking by a set of selection traits, algorithms for determining individual and complex estimated breeding values of rams, ewes, and young animals were developed. This will allow the most rational zootechnical measures and evaluation of fur coat and meat type breeding sheep.

Technical and Economic Analysis of Sheep Breeding Enterprises in Selcuklu District of Konya Province

Bu çalışmada; Konya ili Selçuklu ilçesinde yer alan koyunculuk işletmelerinin yapısal ve ekonomik analiziyle birlikte yetiştiricilerin karşılaştıkları sorunların belirlenmesi amaçlanmıştır. Araştırmanın ana materyalini 2021 yılında Selçuklu ilçesinde koyunculuk faaliyeti yapan 62 adet işletmeden anket yolu ile temin edilen veriler oluşturmuştur. Örnekleme metodu olarak rastgele örnekleme yöntemi kullanılmıştır. Araştırmanın sonuçlarına göre işletmelerde maliyeti oluşturan masraf unsurları arasında %46,1 ile yem giderleri en büyük paya sahip olurken, bunu %40,9 ile işçilik giderleri izlemiştir. İşletmeler büyüdükçe, sabit maliyetlerin toplam maliyetlere oranı azalmıştır. İşletmelerde en büyük gelir unsuru ise %49,8 oranla kuzu geliri olmuştur. İşletmelerde koyun başına düşen satış gelirleri, üretim giderleri ve işletme brüt kârları sırasıyla 1.282 TL; 690 TL ve 592 TL olarak hesaplanmıştır. Çalışmada sonuç olarak Konya ilinde koyunculuk işletmelerinde maliyetlerin düşürülmesi, satış geliri ve kârın artması, işletmelerin profesyonelleşmesi ve işletme ölçeklerinin büyütülmesi önerilmektedir.

The productive longevity of cows depends on the livestock-keeping method

In the article, the authors presented an analysis of the influence of the methods of keeping the breeding stock of Kuzbass cattle on the period of its productive use and life expectancy. The object of the study was the breeding stock of cattle breeding and commercial enterprises. With a tethered method of keeping, the economical use of cows in the breeding enterprises of the region amounted to 2.75 ± 0.27 lactation, or 1002.70 ± 45.19 days, with an average life expectancy of 1835.60 ± 95.42 days. In commodity farms, the economical use of cows is an average of 2.35±0.20 lactations, or 860.70±41.80 days, with an average life expectancy of 1563.67±85.30 days. An analysis of the loose keeping of the cattle breeding stock showed that the period of economic use in breeding organizations is 2.45 ± 0.19 lactations (896.50 ± 39.43 days), and the average life expectancy is 1693.0 ± 83.34 days. The period of economic use of cows in the commercial farms of the region using loose housing averaged 2.16±0.20 lactations (794.50±38.53 days), and the average life expectancy was 1688.93±91.50 days. In the winter, the broodstock on tie-down housing has an advantage over the region’s farms in terms of economic use over yearround loose housing by 0.24 lactations (86.20 days).

Productivity of cows depending on the type of mating and genotype of sires

At breeding enterprises, the number of sires of Holstein breed homozygous for the genotype of the ЕАВ-locus is increasing, and there is a tendency for inbreeding coefficients to increase in populations of this breed. The dairy productivity of fi rst-calf heifers obtained from heterozygous and homozygous sires, as well as the change in indicators per generation with intra-line mating and line crosses were studied. It was found that in terms of the total yield of milk fat and protein for 305 days of lactation in the line Wes Back Ideal 1013415, the fi rst-calf heifers obtained from intra-line mating and line crossing exceeded the cows their mothers by 21,4 kg, and in the whole group of fi rst-calf heifers of homozygous sires this indicator was 51,0 kg higher against the average of fi rst-calf heifers of heterozygous sires. At the same time, for the cow-mothers of these groups, the corresponding diff erence was negative: –31,6 and –64,7 kg. Similar data were revealed for another main line Refl ection Sovereign 198998. When mating heterozygous sires according to the variants of line crosses, the milk yield was 227 kg higher (p < 0,05), but the mass fat fraction in milk decreased by 0,06 – 0,08 abs.% (p < 0,01). However, the levels of manifestation of traits among fi rst-calf heifers in comparison with cow-mothers with intra-line mating increased by groups of homozygous sires in milk yield by 32,5 %, mass fat fraction by 17,6 % and mass protein fraction by 25,0 %. The correlation coefficients «mother – daughter» for milk yield, mass fat fraction and mass protein fraction were relatively higher in the group of homozygous sires, whose heritability coeffi cient in one of the farms for milk yield was higher by 0,495, mass fat fraction by 0,305; mass protein fraction by –0,110, and in the other, respectively, by 0,026; 0,161; 0,121. The conclusion is made about a higher prepotency of heterozygous sires with improving mating.

Direction of selection and breeding work on the formation of a new competitive factory type of yorkshire pigs using and genetic techniques and methods

For modern domestic breeding programs to be implemented, population genetic techniques and methods must be applied in order to create new types of lines with superior performance characteristics, the use of which will contribute to the efficient pedigree livestock farming. Genomic selection use in domestic breeding programs accelerates genetic progress in herds by determining the breeding value of animals at an early age, and thereby contributes to the development of local animal husbandry and to the reduction of dependence on imports of foreign pedigree material. The article contains the data of the studies that were aimed at forming breeding herds of a new competitive factory type of Yorkshire pigs with the use of genetic techniques and methods. The study included the analysis of productivity marker genes and DNA testing by microsatellite markers of the initial genotypes. It was found that in the populations, young animals with preferred genotypes outperformed their peers in productive traits by 1.95–42.3 % (p ≤ 0.05). The use of the DNA-MS analysis of the animals tested at basic breeding enterprises allowed determining their genetic affiliation with the Belarusian population of the Yorkshire breed on the basis of the genetic distance and allele frequency in the loci under study that were in the range 5.665–11.084.

Study on the Influence of Different Factors on Pneumatic Conveying in Horizontal Pipe

Aiming at the problems of high energy consumption and particle breakage in the pneumatic conveying process of large-scale breeding enterprises, in this paper, based on the theoretical calculated value of particle suspension velocity, a computational fluid model and a discrete element model are established based on computational fluid dynamics (CFD) and discrete element method (DEM). Then, through the numerical simulation of gas-solid two-phase flow, the influence of four factors of conveying wind speed, particle mass flow rate, pipe diameter, and particle size on the velocity distribution of particles in a horizontal pipe, dynamic pressure change in the pipe, pressure drop in the pipe, and solid mass concentration are studied. The results show that the k-ε turbulence model can better simulate the movement of gas-solid two-phase flow, and through the analysis of the simulation, the influence of four different factors on the conveying characteristics is obtained, which provides a scientific basis for the construction of the conveying line.

Semen quality analysis of the Airshire bulls in relation to the AH1 fertility haplotype

The results of the studies (2019-2021) of increased incidence of genetic mutations, such as fertility haplotypes, in the population that result in lower reproductive rates in dairy cattle are presented. Semen quality of the Ayrshire breed bulls was evaluated for motility and morphological indices due to rs475678587 in the UBE3B gene locus associated with the AH1 fertility haplotype. Semen samples (n = 14) were obtained from the Center of Collective Use "Genetic Semen Collection of Domestic and Foreign Cattle Breeds" of the All-Russian Research Institute of Farm Animal Genetics and Breeding (ARRIFAGB) and belonged to the animals born in 2014 and older (average age of bulls was 6-15 years). Genotyping for rs475678587 of the UBE3B gene was performed by Sanger sequencing. Animals with the heterozygous CT genotype were defined as carriers of the AH1 haplotype (AH1-C), and those with the homozygous CC genotype were defined as free of the AH1 haplotype (AH1-F). Frozen-thawed semen was evaluated according to the following parameters: total and progressive motility, percentage of normal spermatozoa. Morphological indices of sperm quality were assessed after differential staining of cellular elements of spermatozoa using a commercial kit "Diakhim-Diff Quick" (ABRIS+ scientific and production company) in sperm smears. The following indicators were taken into account: acrosomal abnormalities, abnormalities in the head, tail, and neck of the spermatozoon. Data on the indicators of native semen (motility, concentration), obtained immediately after collection, were received from the archive of the technical service of the breeding enterprise. The results of the studies have shown that according to physiological and morphological indices the semen obtained from the bulls carrying the haplotype AN1 did not differ significantly from those of the bulls free of the mutation. In terms of total motility, the semen of the haplotype fertility carrier bulls was almost 2% higher than that of the haplotype free bulls. It can be noted that the haplotype carriers of fertility bulls were generally characterized by good sperm fertility indices.

Study on Environmental Cost Control in Pig Scale Breeding

The cost of pig breeding enterprises in China remains high and the benefits are declining. How to reduce costs and increase efficiency is an important practical problem faced by pig breeding enterprises at present. This paper takes New Hope Group as the research object, based on its aquaculture management model and financial data, deeply reveals the problems in its large-scale aquaculture management and cost control, and defines the connotation and objectives of environmental cost control of aquaculture enterprises from the perspective of changing the engineering construction model; Secondly, it analyzes the current situation and problems of environmental costs in pig farms; Then put forward the optimization plan of environmental cost in three stages, namely, before, during and after the event. Finally, using the method of combining theory with practice, put forward that enterprises should build an environmental cost control system and supporting measures for the return of manure to farmland.

Research on multiple co-governance of agricultural non-point source pollution in China on the perspective of ENGOs and public participation.

Effective prevention and control of agricultural non-point source pollution is a major challenge faced by the Chinese local government in the context of rural revitalization, and clarifying the game relationship between stakeholders in agricultural non-point source pollution control actions will help achieve multiple co-governance better. Accordingly, this paper discusses the interactive decision-making relationships between local government and livestock and poultry breeding enterprise (LPBE) under the participation of Environmental non-government organizations (ENGOs) and public, by constructing an evolutionary game model, as well as analyzing evolutionary cooperative stability strategies and realizing the simulation of evolution processes in different scenarios by MATLAB. The results show that government subsidy has an incentive effect on LPBE to adopt the purifying strategy, yet reduces the enthusiasm of local government for supervision. Improving the participation degree and right space of ENGOs is conducive to the realization of multiple co-governance models. Furthermore, the impact of public participation on multiple co-governance of agricultural non-point source pollution is related to the local government's investigation rate and the public reporting fairness; strengthening the local government's supervision capacity and improving the public reporting fairness can achieve better collaborative governance effects.

Дослідження перспектив використання агробіомаси в напрямку забезпечення екологічної та енергетичної незалежності підприємств АПК

The article conducts a study indicating the importance of bioenergy as one of the main directions of renewable energy. Bioenergy occupies a leading position in the global market and plays a significant role in replacing fossil fuels and reducing greenhouse gas emissions. Bioenergy, in particular the use of agrobiomass, has great potential in Ukraine for energy production. However, now the development of bioenergy in the country lags behind the European level. In order to facilitate the development of this industry, it is necessary to use the available agrobiomass resources and introduce modern energy production technologies. It is further defined that for the development of bioenergy in Ukraine it is important to create a favorable legislative environment and infrastructure. It is necessary to attract investment in the industry, support research and development of new technologies, as well as have specialists trained who can effectively implement bioenergy projects. The study revealed that one of the ways to use agrobiomass for energy production is to grow energy crops such as straw, corn and sunflower stalks, corn silage, organic components of household waste, sewage sludge and waste from livestock breeding enterprises. For optimal use of agrobiomass, it is necessary to take into account environmental and socioeconomic aspects, ensure the sustainability of raw material supplies and develop efficient production technologies. The publication provides data on the consumption of renewable heat energy in Ukraine during 2007–2024. Different types and methods of energy production from agrobiomass are described and a classification of technologies for the gradual transformation of agrobiomass into energy products is presented. The publication also considers the methodology of economic efficiency of waste use for biofuel production in comparison with their traditional use at the State level. The advantages and disadvantages of energy use of agrobiomass are highlighted, as well as different types of biofuel production and raw materials used for this purpose are considered.

ФОРМИРОВАНИЕ ГЕНЕАЛОГИЧЕСКОЙ СТРУКТУРЫ ПОГОЛОВЬЯ БЫКОПРОИЗВОДЯЩИХ КОРОВ И ПЛЕМЕННЫХ БЫКОВ ГОЛШТИНСКОЙ ПОРОДЫ МОЛОЧНОГО СКОТА ОТЕЧЕСТВЕННОЙ СЕЛЕКЦИИ В ПЛЕМЕННЫХ СЕЛЬСКОХОЗЯЙСТВЕННЫХ ПРЕДПРИЯТИЯХ МИНСКОЙ ОБЛАСТИ С УЧЕТОМ ГЕНОТИПОВ ПО β -КАЗЕИНУ

For the first time in the Republic of Belarus, following the example of agricultural enterprises of the Minsk region, there has been formed the genealogical structure in herds of bull-producing cows and breeding bulls of the Holstein dairy cattle breed of domestic selection, considering the β -casein genotypes. It has been established that animals with the A2A2 β -casein genotype belong to all six planned genealogical complexes that make up the structure of the Holstein breed. The RUAE Minsk Pedigree Breeding Enterprise possesses a sufficient stock of sperm doses taken from breeding bulls with the A2A2 β -casein genotype to obtain replacement bulls of all complexes and develop selection herds with the desired genotype, producing A2 milk.

ДИНАМИКА РАЗВИТИЯ ЖИВОТНОВОДСТВА В ЕВРЕЙСКОЙ АВТОНОМНОЙ ОБЛАСТИ

The article, based on an analysis of statistical indicators of livestock farming in the Jewish Autonomous region for 1990–2021, reveals negative dynamics in the development of the industry. When considering the cattle livestock, including pigs, sheep and goats, vertical and horizontal methods are used. They provide an objective assessment of the livestock industry dynamics. It is noted that in the 90s of the last century the region was a fairly large producer of agricultural products, providing both the region and other areas of the Russian Far East with agricultural products. Over the past few decades, agriculture in the region has undergone a significant decline, negatively affecting the economy of the region. It is determined that the cattle breeding development in the region, which needs capital intensity, suffers from the lack of large manufactures. The forage crops sown areas analysis also shows negative dynamics. And this is one of the leading reasons for the cattle livestock decline. It is substantiated that the population outflow from rural areas results in the decline of agricultural production. To the author, the predominant agricultural producers in the Jewish Autonomous region are households. It is noted that modern state support options aimed at the regional agriculture development are not efficient enough. For its rise and development, the branch needs large cattle breeding enterprises and participation of agricultural holdings in the production process.

Методологическое обоснование комплексного экономического развития предприятий мясного скотоводства

The article presents an expert assessment of the potential of integrated development of beef cattle breeding enterprises. The key indicators forming the potential of integrated development are given. The subjective expert assessment of the integral indicator of the integrated development potential of the meat cattle breeding enterprise is considered. The mathematical model of the optimal project of integrated development at the enterprise for the cultivation of beef cattle is presented. This model is considered on the example of enterprises for the cultivation of cattle in the meat production area. The given objective function of integrated development is aimed at the socio-ecological and economic development of beef cattle breeding enterprises.

A regional-scale assessment of nutritional-system strategies for abatement of enteric methane from grazing livestock

Progress towards methane (CH4) mitigation for the red meat, milk and wool sectors in Australia and reduced CH4 emissions intensity (g CH4/kg animal product, typically milk or liveweight gain) involves not only reduced net emissions but also improved productive efficiency. Although nutritional additives have potential to reduce CH4 production rate of livestock (g CH4/head.day), systemic improvement of the nutrition of grazing breeding females, the largest source of CH4 emissions in Australian agriculture, will also be required to reduce emissions intensity. Systemic changes that increase productive efficiency for producers are part of the economic and environmental ‘win–win’ of reducing emissions intensity, and so offer good potential for adoption by industry. For sheep and cattle breeding enterprises, improved nutrition to achieve a younger age at first joining and increased reproductive rate will reduce the proportion of CH4-emitting, but unproductive, animals in a herd. However, if breeding stock are managed to be more productive (e.g. by superior nutrition leading to greater product/breeder) and more efficient (e.g. greater product per kilogram DMI) the producer is faced with the following management challenge. Should the enterprise increase stock numbers to utilise surplus feed and gain extra product, or reduce stock numbers to maintain previous product output with smaller enterprise net emissions (and emissions intensity), and so make land available for other uses (e.g. tree plantings, conservation zones). The right balance of incentives and price on carbon is necessary to achieve a result whereby total emissions from Australian agriculture are reduced, and so a positive impact on climate change is achieved.

Identification of Differentially Expressed miRNAs in Porcine Adipose Tissues and Evaluation of Their Effects on Feed Efficiency

Feed efficiency (FE) is a very important trait affecting the economic benefits of pig breeding enterprises. Adipose tissue can modulate a variety of processes such as feed intake, energy metabolism and systemic physiological processes. However, the mechanism by which microRNAs (miRNAs) in adipose tissues regulate FE remains largely unknown. Therefore, this study aimed to screen potential miRNAs related to FE through miRNA sequencing. The miRNA profiles in porcine adipose tissues were obtained and 14 miRNAs were identified differentially expressed in adipose tissues of pigs with extreme differences in FE, of which 9 were down-regulated and 5 were up-regulated. GO and KEGG analyses indicated that these miRNAs were significantly related to lipid metabolism and these miRNAs modulated FE by regulating lipid metabolism. Subsequently, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) of five randomly selected DEMs was used to verify the reliability of miRNA-seq data. Furthermore, 39 differentially expressed target genes of these DEMs were obtained, and DEMs-target mRNA interaction networks were constructed. In addition, the most significantly down-regulated miRNAs, ssc-miR-122-5p and ssc-miR-192, might be the key miRNAs for FE. Our results reveal the mechanism by which adipose miRNAs regulate feed efficiency in pigs. This study provides a theoretical basis for the further study of swine feed efficiency improvement.

Analysis of the breeding base of pig breeding in Ukraine

Goal. The comparative analysis of productive traits of different breeds of breeding pigs of Ukraine. The research method is the analysis and comparison of indexes of the development and productivity of pigs of different breeds, changes in the number of animals and subjects of the breeding business in pig breeding during 2017– 2021. The results. The analysis of the state of the breeding base of pig breeding in Ukraine over the course of five years shows the reduction of 31 subjects of the breeding business with a herd of about 7,000 heads of the main sows. As of January 1, 2022, there are 67 breeding enterprises, including 27 breeding factories and 40 breeding farms. To date, pig breeding is represented by 10 breeds of pigs, the most numerous of which are two breeds – the Large White - 60% and Landrace 31.3%, which are bred in 18 and 13 regions of Ukraine, respectively. The largest number of pigs are bred in Kyiv (624,800 heads), Lviv (430,000 heads), Donetsk (405,400 heads) and Ternopil (377,000 heads) regions. And the smallest population is concentrated in Luhansk (40.9 thousand heads) and Kherson (49.5 thousand heads) regions. It was determined that the tendency to increase the stock at the beginning of 2022 was observed in Durok breeds (from 1.98 to 2.47%), Pietren (from 1.58 to 2.08 %), the Red White-belted breeds (0, 23 to 0.33), Wales (from 0.47 to 0.58%) and Ukrainian Steppe White breed (0.96 to 1.26 %). For the rest of the domestic breeds, such as Poltava Meat, Ukrainian Meat and Ukrainian Steppe piked, a clear tendency to decrease was observed, respectively, by 0.13; 0.02 and 0.04%. The analysis of productive traits shows that the reproductive qualities of sows bred in breeding factories are higher than those of breeding farms, this applies to such breeds as Landras, Durok, Poltava Meat. The advantage according to the multifertility index was 1.4 heads, 1.5 heads, 1.0 heads, respectively. As for Welsh and Durok breeds, which are considered meat breeds, but are distinguished by high reproductive qualities (multifertility of the Welsh breed – 13 heads, Durok – 11.6 heads). It is explained, in our opinion, by purposeful selection work aimed at increasing the fertility rate. The reproductive traits of other meat genotypes remain as they meet the requirements for meat genotypes. Conclusions. It is necessary to increase the breed gene fund of Ukraine in order to fully implement selection and genetic programs for the improvement of breeds, as well as interbreed crossing and hybridization. Key words: pedigree pig breeding, breeds, breeding factories, breeding farms, reproductive traits, lard thickness, hybridization.

Стрессоустойчивость коров черно-пестрой породы зоны Урала

Abstract. In the Urals, one of the numerous breeds of cattle for the production of dairy products is common – black and motley. In recent years, there has been a tendency to decrease the level of livestock with an increase in their productivity indicators and a decrease in the duration of economic use. Scientific novelty. An assessment of the types of stress resistance of cows-daughters from among the first heifers, depending on the highest milk productivity of their mothers, was carried out, bulls-improvers were identified by the type of stress resistance of daughters. The purpose of the research was to study the stress resistance of cows of the black-and-white breed of the Urals. Research methods. The work was carried out in cattle herds of high-tech breeding enterprises of the Sverdlovsk region. 3315 daughters of 34 bulls-producers of various lines were evaluated to identify bulls-improvers on the stress resistance of offspring. The assessment was carried out in two stages: 1) breeding bulls were selected whose daughters did not reduce milk yield with seasonal changes in conditions of detention; 2) bulls whose resistance rank did not exceed the rehabilitation rank were identified by the method of overlapping breeding fields. At the same time, the reaction of the daughters of bulls to stress was assessed using the indices of reduction (Id) and recovery (Ir) of the value of milk yield per month. Results. It was found that the cows-daughters of the evaluated bulls-producers differed in the level of resistance to seasonal changes in housing conditions. Reliable bulls-improvers in terms of the level of stress resistance of offspring have been identified: Potter 128367894, Stardel 658867, Marcos 131801949 and Thaler 4091. The low type of stress resistance of cows-daughters was noted in the group of highly productive cows-mothers – 25 % of heads. In addition, the dependence of the level of stress resistance with the origin of cattle is also noted by other scientists, which confirms the need to carry out breeding work with dairy cattle with the inclusion of stress resistance of animals in the selection indicators.

Analysis of the state of development of breeding livestock in Ukraine

Breeding of agricultural animals in Ukraine is a complex system consisting of many stages. Successful selection work includes a whole set of very important measures. In the conditions of wartime, the issue of animal husbandry development, in the direction of tribal affairs, acquires special relevance and requires further research. Therefore, the aim of the work was to study aspects of the territorial distribution of breeding animals in Ukraine. Research has established that the share of agriculture in the country's GDP has a tendency to grow: from 12.26% in 2017 to 16.87% in 2021. This is due to the reduction in the rate of GDP growth and the increase in the rate of volume growth agricultural activity. Over the last 10 years, crop production prevailed (more than 70%), while livestock production occupied less than 30%, respectively. The largest share of animal husbandry was recorded in 2010 – 29.48%, and the smallest in 2019 – 20.89%. In 2020, there was an increase in live weight of farm animals, compared to 2019, but compared to 2015, there was a reduction of more than 12%. According to research, in 2020 there was an increase in live weight of farm animals, compared to 2019, but compared to 2015, there was a reduction of more than 12%. The organization of reproduction of the herd is of great national economic importance, since the acceleration of the intensification of animal husbandry depends on it. One of the main issues in the reproduction of animal husbandry is the systematic replacement of animals culled due to disease, old age or low productivity with younger and more productive animals, i.e. herd repair. In recent years, 6 regional selection centers and 64 inter-district own breeding enterprises, 1516 posts for artificial insemination of cows and heifers in the individual sector were created in Ukraine. In addition, based on the report of the Ministry of Agrarian Policy and Food of Ukraine, it was established that the genetically guaranteed level of productivity of animals of these breeds is: milk productivity in 305 days of lactation, 5200-6400 kilograms of milk, average daily gain of young meat breeds – 1200 grams, pigs – 790-980 grams, sheared wool in pure fiber – 4.5-5.3 kg, which is 3 times higher than the average indicators for Ukraine. Further research will be the next stage in the development of measures for the development of animal husbandry in the Rivne region and Ukraine in particular.

Reproductive and respiratory syndrome of pigs in pig breeding enterprises (review)

Porcine Reproductive Respiratory Syndrome (PRRS) causes significant economic losses in pig production around the world. The virus is highly contagious and spreads both by aerosol and with all biological secretions, and the disease itself is characterized by fever, weight loss and abortion of fetuses. This swine disease is relatively new, for the first-time clinical signs were described in 1986, and in 1991 the pathogen was isolated. The main problems hindering the fight against the virus currently remain: the insufficient effectiveness of existing vaccines, the high genetic variability of the pathogen, the ability of PRRSV to suppress the host's immune system, and long-term virus carriers in recovered animals. The review on porcine reproductive and respiratory syndrome presents data on the genetic diversity of virus strains that differ in the degree of virulence and pathogenicity, sources of infection and ways of transmission of the virus. The article also contains data on the spread of PRRS in the world and in Russia. It is noted that the disease has been reported in many swine-producing countries, where, after a phase of active spread, the disease became endemic. And in 2021, according to the to the International Epizootic Bureau (OIE), outbreaks of PRRSV were detected in domestic pigs in Ecuador, Uruguay, Nepal, China, Bahrain, Switzerland and Ukraine, as well as in wild boars in Bahrain, Switzerland and Ukraine. According to the published data of monitoring studies conducted in the period from 2012 to 2017, only single territorially limited outbreaks were detected in Russia. Earlier studies indicate a wide distribution of the PRRS pathogen in Russia. The effectiveness of various variants of live and inactivated vaccines is described in detail, and it has been established that live attenuated vaccines are most effective against PRRS. The features of the protection of the territory of a number of states (Norway, Sweden, Finland, Switzerland) from the introduction of the pathogen, which by now remain free from PRRS, as well as the experience of Hungary in the eradication of the disease, are analyzed. All preventive measures in the pig farm in case of detection of the virus should include general, veterinary-sanitary and special measures, for diagnosis it is better to use modern RT-PCR test systems that allow distinguishing PRRS genotypes, in combination with serological tests, and for vaccination choose a registered and approved vaccine based on the genetic characteristics of the pathogen circulating in the area.

THE INFLUENCE OF BREED AFFILIATION ON THE REASONS FOR CULLING OF SERVICE BOARS

According to the results of three-year research in the center of genetics and selection of the Grodno regional breeding enterprise, the main reasons for culling of service boars (diseases of tendons, joints, digestive organs, cardiovascular system) and the influence of their breed affiliation on the age of removal from the herd due to diseases, reduced productivity were established. The average age of culled Yorkshire, Landrace and Duroc boars was : 33.3, 31.2 and 29.9 months due to tendon diseases, 35.8, 40.8 and 30.2 months due to joint diseases, 37.5, 35.0 and 27.0 months due to cardiovascular diseases, respectively. The average age of boars culled in terms of sperm production quality was : Yorkshire - 25.9 months, Landrace - 38.8 months, Duroc - 29.7 months. The average age of pigs culled due to old age in the Yorkshire breed was 71.9 months, in the Landrace - 64.8 months.