Nodular dermatitis is a highly contagious viral disease that causes fever, damage to the skin, mucous membranes and lymphatic system. It is one of the most dangerous transboundary animal diseases requiring an integrated approach to prevention: systematic vaccination, strict veterinary control, vector control and international cooperation.

The economic consequences of the disease underscore the need for timely response and the introduction of modern control strategies, which is important for agriculture and international trade.

Blastocystosis, caused by the protest Blastocystis spp., is a widespread but understudied invasion in farm animals, whose pathogenic role remains controversial.

Microscopic examination of 288 fecal samples from calves up to 30 days old confirmed the invasion in 72 samples (25 % of cases). A comparative immunological analysis of blood from infected and pathogen-free calves revealed statistically significant changes. In diseased calves, a significant decrease in the relative count of total Tlymphocytes (CD3+) by 18,86 % and T-helper cells (CD4+) by 1,81 % was established, indicating the immunosuppressive effect of the pathogen. Simultaneously, lymphopenia (a decrease of 23,04 %) and a significant increase in the level of band neutrophils (by 1,62 times) were noted, indicating the development of a pronounced inflammatory process.

The data obtained indicate that blastocystosis in calves is accompanied by a complex violation of the immune response, characterized by an imbalance in the cellular link of immunity and chronic inflammation. This must be taken into account when developing treatment and preventive measures.

This article presents data on the effect of the developed inactivated vaccine for the prevention of coronavirus infection and pasteurellosis on the hematological and immunological parameters of fur animals. It has been established that the use of the developed biological drug leads to the formation of an immune response. The introduction of the named causes a reliable increase in the titer of antiviral and antibacterial antibodies, the number of T- and B-lymphocytes, lysozyme and bactericidal activity of blood serum.

The article describes production of recombinant strains-producers of Escherichia coli synthesizing recombinant proteins of M. bovis and M. hyopneumoniae and evaluation of antigenic properties of membrane proteins synthesized by them. Obtained results demonstrate expressed antigenic properties of recombinant proteins and confirm perspective of created strains-producers for obtaining standardised antigenic preparations, suitable for use in ELISA-test systems for diagnostics of farm animal mycoplasmosis.

A multiplex real-time PCR method has been developed for the simultaneous detection and differentiation of infectious agents of bovine keratoconjunctivitis - Moraxella bovis and Moraxella bovoculi. The method is based on the use of original primers and probes to the conserved genes of cytotoxins MbxA and MbvA, which ensures its high specificity. The optimization showed a sensitivity of 3,8×10³ CFU/mL for M. bovis and 6,5×10³ CFU/mL for M. bovoculi, which allows effective detection of both mono- and mixed-infection in clinical material.

Recombinant antigens of the African swine fever virus (ASF) have been developed by cloning and expressing proteins encoded by two genes of this virus: p72 (B646L) and p30 (CP204L). The parameters of adsorption of recombinant proteins of the African swine fever virus have been worked out and optimal concentrations of ELISA diagnostic components have been determined for the detection of antibodies to antigens of the African swine fever virus. An ELISA diagnosticum has been developed to detect specific antibodies to the African swine fever virus. Rabbits were immunized and specific serums for the African swine fever virus were obtained. The selection of optimal concentrations of diagnostic components for the detection of antibodies to the ASF virus antigen was carried out. The developed ELISA diagnostic was tested in terms of specificity and sensitivity.

In the reproductive pathology of pigs, the porcine reproductive and respiratory syndrome virus (RRSS) plays a special role. For the rapid, highly sensitive and specific detection of the viral genome, molecular biological methods, primarily polymerase chain reaction (PCR), have become widespread. Modern developments are aimed at creating diagnostic test systems that allow high efficiency to identify the pathogen genome in the sample, which significantly reduces the time and cost of testing. The developed method makes it possible to identify the RRSS virus genome in various biological material (blood serum, parenchymal organs, virus isolates) with high sensitivity. The study of the above infection showed its widespread distribution in the pathology of pigs.

 Thus, the seropositivity of pigs to the PRRS virus on individual pig farms is 77,5 %.

Recombinant interferons are actively used in the treatment and prevention of viral diseases in farm animals. One of the most important quality indicators reflecting the effectiveness and safety of interferon preparations is specific antiviral activity. A biological method was used to determine the activity of interferons. The estimation of the specific activity of interferons on the MDBK cell line was studied. The presence of specific antiviral activity of interferon compositions has been shown.

This article analyzes the effectiveness of the probiotic «Promois» in raising broiler chickens in the Republic of Iraq. Productive indicators, such as chicken weight increased by 8,8 %, feed conversion decreased by 7,5 %, and average daily gain increased by 8,6 %, while mortality was reduced by 2,4 times compared to the control group. Characteristic stages of hematological parameter changes were identified. These changes followed a lymphocytic pattern, accompanied by an increase in lymphocytes, eosinophil′s, and basophils. The drug resulted in a persistent increase in protein metabolism, with total serum protein levels increasing by 19,2 %, albumin by 33,3 %, and globulin by 22,4 %. The probiotic stimulates angiogenesis in the alimentary system, resulting in a 26,1 % increase in capillary density in the duodenum and a 67,3 % decrease in intercapillary distance. The increased capillary density ensures a highly reliable immunological barrier in the digestive system against feed toxic substances and pathogens.

The article reflects the stages of selecting compositions for the creation of a powder disinfectant for the sanitization of veterinary surveillance facilities and the results of its antimicrobial activity and toxicity.