The article is devoted to the current problem of differential diagnosis of diseases of viral etiology in farm animals. Viral diseases are currently widespread, occupy a leading role in the infectious pathology of farm animals, causing enormous economic damage. Given the magnitude of animal vaccine prophylaxis, in order to increase the effectiveness of antiepizootic measures, the urgent issue i s the development of methods for the rapid and effective detection and differentiation of field and vaccine strains of the infectious rhinotracheitis virus in cattle. The possibility of using a polymerase chain reaction to identify and differentiate a vacc ine strain from epizootic strains and isolators of the cattle infectious rhinotracheitis virus is considered. In the process of research, a PCR-RFLP analysis method was developed to detect the IRT virus in the test material. The PCRRFLP analysis method was used to identify and differentiate the vaccine strain TK-A form epizootic strains and isolators of the cattle IRT virus. The principle of PCR, based on repeated repetition of DNA cycles, annealing and synthesis, which leads to an increase in the number of specific DNA fragments of the pathogen, allows you to take into account the results of PCR in an agarose gel. Analysis time is about 30 hours. The sensitivity of detecting viral DNA is 1-10 picograms (102 TCD). Due to characteristics such as relative simplicity and reaction rate, high sensitivity, specificity and reproducibility, PCR has recently become widespread in basic and applied research in various fields of biological science, including veterinary virology. The results obtained during the studies show that the use of PCR-RFLP allows to differentiate field and vaccine strains and isolates of the IRT virus with a high degree of reliability. The use of PCR -RFLP analysis increases the efficiency and informativeness of studies in the molecular epizootol ogy of cattle RTI, as it allows not only to identify the DNA of different virus strains regardless of their nature, but also to differentiate between them, including differentiating the strain TK-A used for the production of attenuated vaccines against epizootic strains and isolates of the virus.

Combustion engines operate over a wide range of power and speed. To the greatest extent, this applies to automotive and tractor engines and diesel engines operating at fractional and idle loads for a significant part of the operating time. When designing engines, the choice of their main design and layout parameters is carried out in a comprehensive manner, taking into account the provision of the required power and efficiency in the modes of maximum torque and rated power. However, ensuring the economical operation of modern highly accelerated diesel engines at low loads and idling causes a whole range of problems related mainly to the organization of effective mixture formation and fuel burnout, as well as to ensuring stable fuel supply. Thus, the cycle dose of injected fuel in idle mode is 8–12 times less than the cycle dose in nominal mode, which determines increased requirements for fuel equipment and difficulties in ensuring high-quality mixture formation. At the same time, diesel engines operate in idle mode up to 50 % of the total operating time, consuming up to 15–20% of the fuel. For truck engines, the relative idle time is approximately 20–25 %. Thus, the development of measures to improve the efficiency of diesel engines at idle is relevant. The purpose is to perform a numerical analysis of the effect of switching off cycles in diesel engines for autotractor and diesel locomotive purposes on the working processes in the cylinder and the indicator parameters of the cycle in idle modes. When writing the article, traditional methods (comparison, description, and measurement), generallogical methods and research techniques (analysis, generalization, etc.) were used. A numerical analysis of the operating cycle of a diesel engine equipped with a cycle shutdown system was performed. The relationship between changes in fuel injection characteristics when cycles are turned off with indicator indicators of the engine operating cycle in idle load modes is disclosed. It has been established that the expediency of switching off cycles in a specific engine operation mode is determined primarily by the features of the injection, carburetion and fuel burnout processes.

The variety of species and forms of parasites of agricultural animals and the features of their life cycles are the basic foundation for the production of different types and medical forms of antiparasite medicine. In the treatment of the parasitic diseases of agricultural animals, one of the main factors is that the veterinary doctors have the knowledge on the mechanics, efficiency and the safety for humans and environment of the medicine being used. Taking into account high pathogenicity and resistance of parasitic organisms and their ability to adapt to effect of medicine, it is crucial to permanently monitor the efficiency of the applied anthelmintic drugs, including the new drugs offered by veterinary services. This article will describe the results of the research on pharmacodynamic and pharmacokinetic parameters of «Ivermectinum», «Ivermec», «Aversect-1», «Аvrsect-2», «Аivin» drugs and their methods of application with the consideration of terms of maintenance and immune status of cattle herds in Mayconyr village (Irtysh district, Pavlodar region). A comparative analysis of efficiency of the above mentioned drugs in dehelmintization and treatment of cattle was conducted with the results provided. The recommendations and the restrictions on use of the drugs were determined considering the farm condition. The experimental research of the aforementioned broad-spectrum drugs was conducted strictly following the rules of asepsis and instructions on application. The total number of replacement heifers subjected to the dehelmintization under the method of analogues is 150 units. Anthelmintic treatment was conducted two times a year - in springtime (March-April) before pasturage, and fall time (September-October) before confining the cattle in the stable. Coprological study on intestinal helminthes of the examined cattle was conducted in Irtysh RVL of the Pavlodar regional branch of RVE RVL VCaSC MA RK by ovoscopical, flotation and larvoscopical methods. There is a comparative analysis on the efficiency of avermectin group antiparasitic drugs applied twice a year for cattle dehelmintization. The recommendations on the use of the aforementioned drugs for dehelmentization and prevention of parasitic diseases are provided and the requirements for the use were determined.