The first and the main link in the system of prevention of the occurrence and distribution of avian influenza and Newcastle disease is monitoring and the effective prophylaxis of the above diseases. At the same time the conducting of disinfection of the objects of veterinary control is an important stage in the system of veterinary and sanitary measures. A number of disinfectants that contain different classes of chemical compounds as active substances have been developed and proposed for practical use. The large-scale production of disinfectants and their introduction into practice is impossible without the preliminary laboratory assessment of their antimicrobial properties, the determination of the spectrum of their biocidal effect and physical, chemical and toxicological properties. The aim of our work was to study the virucidal properties of a new aldehyde disinfectant using the test models of the viruses of Newcastle disease and avian influenza. The experiments to study virucidal properties of the disinfectant regarding the viruses of avian influenza and Newcastle disease have been carried out at the Department for Avian Diseases Study of the National Scientific Center ‘Institute of Experimental and Clinical Veterinary Medicine’ in accordance with the guidelines ‘Methods for determining and evaluating the safety and quality of disinfectants and disinfecting detergents used in the production, storage, transportation and sale of products of animal origin’ (Kotsiumbas et al., 2010). The determination of the virucidal properties of the disinfectant has been conducted in two stages: stage 1 — the determination of the virucidal activity of the product by the suspension method; stage 2 — determination of the virucidal activity of the product on test objects. As a result of the research conducted by the suspension method the presence of the virucidal properties of the innovative disinfectant (the mixture of quaternary ammonium compounds — 25%, glutar aldehyde — 11%, isopropanol, non-ionic surfactants) for the viruses of avian influenza and Newcastle disease has been determined. It has been found that the above preparation completely inactivated the infective properties of viruses when used in the concentration of 0.1%, with the interval of 30 minutes and in the concentration of 0.5% — 15-minute interval. It has been proved that the use of the disinfectant in 0.1% concentration for 30 minutes disinfected the test objects (wood, metal, tile, textile) that were contaminated by the pathogenic agents of avian influenza and Newcastle disease

The purpose of these studies was to analyse and compare the content of bromine in samples of chicken eggs, feed, and water from different regions of Ukraine in the dynamics of 2016 – 2020: with an increased risk of bromine in products (Kharkiv, Poltava, Dnipropetrovsk and Mykolaiv regions) and outside the risk zone (Volyn, Vinnytsia and Zaporizhzhia). Studies of bromine content in eggs, feed, and water were performed in the laboratory of toxicological monitoring of the National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine" (Kharkiv) using X-ray fluorescence analysis. As a result of the conducted researches, the increase of the bromine content in chicken eggs in the dynamics of 2016 – 2020 was established: the bromine content increased regardless of the region of the poultry farm location. The highest bromine concentration in chicken eggs was found in Kharkiv, Dnipropetrovsk, Mykolaiv, and Zaporizhia regions. Bromine source in poultry products is the excessive intake of bromine in the poultry body with alimentary environmental factors (feed and water). Bromine content in feed for chickens increased in the research dynamics (from 35.1% in the Poltava region to 2.5 times in the Zaporizhzhia region). It exceeded the established EFSA (4.4% of the total) and the average in Ukraine (51.2% of the total number of samples). In addition, the average bromine content in feed from poultry farms of the studied regions of Ukraine correlated with the number of registered and approved bromine-containing pesticides. The average bromine concentration in water sources in the studied regions of Ukraine had no significant differences compared to the beginning of the study but exceeded the maximum allowable concentration by 21.7% in 2016, 34.8% in 2018 and 39.1% in 2020. The maximum bromine concentration was in water sources in Mykolayiv, Kharkiv, and Dnipropetrovsk regions.

A total of 38 species of mosquitoes of the Culicidae family of two subfamilies Anophelinae and Culicinae belonging to 6 genera, were identified on the territory of Kharkiv Region from 2009 to 2019. Dirofilaria larvae were found in 932 insects, which was 4.46 % of the surveyed mosquitoes. The prevalence of the infection of female mosquitoes by dirofilaria was 4.46 ± 0.24 %, while the mean intensity of dirofilariae was 5.4 ± 2.1. Infection of mosquitoes with dirofilariae is currently detected in 11 districts of Kharkiv Region and the city of Kharkiv. The infection rate of mosquitoes of the genus Aedes was 3.83 ± 0.63 %, of the genus Culex — 0.75 ± 0.34 %, of the genus Anopheles — 0.12 ± 0.39 %, whereas females of the genera Culiseta, Coquillettidia, and Uranotaenia were uninfected. It was found that in Kharkiv Region there were 2 types of canine dirofilariae — Dirofilaria immitis (Leidy, 1856) and Dirofilaria repens (Railliet & Henry, 1911), with a predominance of Dirofilaria repens. For the period from 2009 to 2019, we examined 378 blood samples from dogs (190 males and 188 females) aged from 8 months to 13 years with suspected dirofilariasis. According to the results of the studies, 140 samples were positive, the prevalence of infection by the larvae of Dirofilaria spp. in blood samples from dogs with suspected dirofilariasis was 37.03 ± 0.12 %, while infection with Dirofilaria immitis was 2.86 ± 0.45 %, and Dirofilaria repens — 97.35 ± 0.24 %. The number of positive samples from mongrel dogs was 42 (30 %). It was found that cats are more often amicrofilariaemic than dogs.

The widespread presence of modern high-productive egg crosses of chickens in poultry farms causes some negative consequences, one of which is a decrease in hatchability and survival of young chickens. The worsening of the quality of hatching eggs is associated with a violation of the morphological and biochemical parameters of the shell and shell membranes, which leads to the egg breakage, increased hatchery waste, contamination of young birds with infectious agents, and reduced immune resistance. Modern poultry farming uses a fairly large arsenal of disinfectants of various chemical origins and mechanisms of action. The introduction into practice of disinfectants is not possible without prior laboratory evaluation of their effectiveness as to the object of intended use. The aim of our work was to determine the bactericidal properties of disinfectants with different active substances in relation to the microbiota of hatching eggs from chickens of different productivity directions. The research was conducted following the guidelines ‘Methods for determining and evaluating the safety and quality of disinfectants, detergents and detergent-sanitizers used in the production, storage, transportation and sale of animal products’ (Kotsiumbas et al., 2010). According to the results of the research, it was found that for the purpose of pre-incubation treatment and during the incubation period for chickens it is effective to use the drug ‘Polydez’ in 0.1% concentration and the drug ‘Virosan’ in a concentration of 0.1%. These disinfectants can be used for sanitation of chicken hatching eggs and hatcheries

Correction of sexual function in animals is a topical issue today, despite a large amount of scientific data on this problem. The study aimed to scientifically substantiate the effectiveness of hormonal veterinary drugs in cats and dogs of different breeds and genders. Veterinary drugs with the active substance megestrol acetate were used in the experiments. The studies were performed on clinically healthy cats and dogs of both sexes, different breeds, and ages vaccinated against infectious diseases and treated with antiparasitic drugs. The study was conducted according to the current regulatory documentation. It has been found that the use of hormonal drugs to interrupt/delay estrus in female cats at a dose of 5 mg of megestrol acetate for 8 days leads to a significant decrease in follicle-stimulating hormone, and the content of luteinizing hormone in the blood of cats in the experimental groups reliably decreased throughout the experiment. The use of contraceptives based on megestrol acetate in doses of 2.5 mg for 14 days for cats leads to a reliable decrease in the concentration of testosterone in the serum. It was found that the use of experimental hormonal drugs for female dogs in doses of 5 mg of megestrol acetate per 2.5 kg of body weight in the first 3 days, and half the daily dose from the 4th to the 10th day, leads to a reliable decrease in concentrations of follicle-stimulating and luteinizing hormones in serum compared to the control. Oral administration of experimental hormonal drugs to male dogs in doses of 5 mg of megestrol acetate per 2.5 kg of body weight for 8 days, led to a reliable decrease in the concentration of testosterone in the serum of males. It was found that the estrous cycle in female cats and dogs of the experimental groups after the cessation of hormonal drugs was completely restored, which indicates the safety of drugs with an active ingredient megestrol acetate