The article presents data on a combined viral-bacterial (Streptococcus suis and PRRS) infection of piglets, the most common in modern pig farming, as well as a system for its diagnosis and prevention.

The article presents data on the study of the viral-bacterial profile in pigs of different ages in the farms of the Republic of Belarus. It has been established that the maximum number of PRDC pathogens in most households is iso-lated at the age of 60−80 days, bacterial pathology accumulates gradually and, as a rule, is a secondary infection (with the exception of IAR).

The viral and bacterial profile depends on the epizootic situation in the farm, the most complete list of CRPC pathogens (11 out of 13) was observed in farm No. 4. Primary detection in samples of 60−80 day old piglets of the APP pathogen genome indicates its later infection compared to hemophiliasis pathogens and IAR. Infection with the causative agent of IAR presumably occurs in the post-weaning period up to 40 days.

When sowing 6% oxalic acid decontaminated homogenates of 7-14-day-old calf tissue mixtures incubated in a growth stimulant VKG on MycCel DW nutrient medium, non-acid-fast and partially acid-fast cell wall deficient myco-bacteria tuberculosis (CWD MBT) which are a marker of tuberculosis infection were isolated in 77,8% of cases. Since the calves were 3-14 days old, there was most likely a transplacental transmission of infection and the persistence of MBT in changed forms that were invisible to routine diagnostic methods. This confirms the risk of tuberculin-positive individuals appearing in herds and relapses of the disease without infection, and also calls for further improvement of anti-tuberculosis measures and the use of methods that detect CWD MBT for the formation of uninfected herds.

The article presents data on the persistence of type 2 circovirus in one of the farms of the Republic of Belarus. The presence of the pathogen genome in pigs of different ages was established, and comparative data on the results of PCR and ELISA were presented.

The article describes the etiological structure of pneumoenteritis in cattle (cattle) in livestock farms of the Re-public of Belarus for the period 2020–2021. based on the analysis of the results of our own research and describes the role of associations of viruses involved in their occurrence.

Among the etiological causes of pneumoenteritis in cattle, there are such infections as BVDV, IBR, PIV-3, BRSV, bovine rotavirus and bovine coronavirus infections that cause significant economic damage to livestock. Prevention of diseases is the most important task of modern animal husbandry. In many cases, preventive measures can pre-vent the development of diseases or make their prognosis and consequences more favorable. Prevention and treatment requires rapid and accurate laboratory diagnosis. In addition to establishing the etiology of the disease, laboratory diagnostics is important in establishing the epizootic situation and in organizing anti-epizootic measures.

The article presents the materials of the effect of polyvalent inactivated culture vaccine against infectious rhi-notracheitis, viral diarrhea, parainfluenza-3, respiratory syncytial, rotavirus and coronavirus infection of cattle "BolsheVak" on immunomorphogenesis in rabbits. It was found that double immunization with an interval of 21 days allows for more active development of cellular and humoral immunity in immunized animals.

The article presents studies on effectiveness of use of new complex drug «Virococcid» in associative parasitosis of sheep. Most effective regimen for treatment of associative parasitoses of gastrointestinal tract of sheep is use of complex preparation «Virococcid» at a dose of 100 mg/kg of live weight orally once a day for two days in a row. When it is used in sheep, no side effects, intoxications have been established. The economic efficiency of using virococcid to sheep at a dose of 100 mg/kg of live weight twice amounted to 6.3 rubles per 1 ruble of costs.

The article presents the results of in vivo laboratory tests of a new «Rifizostrep» anti-TB drug. «Rifizostrep» in the organism of experimentally infected 27 guinea pigs. It is obtained that the preparation «Rifizostrep» in organism of guinea pigs at 10 мg/кg dose has sufficient antimicrobial activity against mycobacterium a tuberculosis of type M. bovis and M. tuberculosis

Studies have found that twice with an interval of 5 min. with a duration of exposure of 90 seconds, a complex biophysical effect with certain frequencies: EHF waves (specific flux power 0.5–1 MW/cm2, 53 Ghz – 1 oxygen absorption line, 150 Ghz – 1 nitrogen monoxide absorption line), magnetic waves (24 mTs) and an IR laser (pulse-the operating mode with a clock frequency of 10 kHz) allows minimizing the decrease in sperm motility during storage up to 50 % (the difference with the control is 10 p.p.), increasing the degree of integrity of sperm cell membranes by 7 %. The use of the method of intensification of motor activity and strengthening the morphological integrity of sperm through a complex biophysical effect on the biomaterial of boars-producers significantly contributes to an increase in fertilization by 10–20 pp compared with the control and 10–20 pp compared with analogues from other experimental groups, the total number of piglets born by 10 and 1,5–8,0 %, live – by 11.0 and 5,0–9,0 % in comparison with sows from the control and other experimental groups, respectively.