The paper presents the results of a study on the formation of colostral immunity and the determination of its duration during the first months of life of calves according to the indications of the level of total IgG and antigen-specific antibodies to pathogens of рarainfluenza 3, respiratory syncytial infection and viral diarrhea of cattle. It has been established that blood serum of newborn calves does not contain antigen-specific immunoglobulins of class G to pathogens of viral diarrhea, respiratory syncytial infection and parainfluenza-3, and the level of total IgG is 2.2 ± 0.61 g/dm3. The concentration of total IgG is increased to 50.50 ± 6.33 g/dm3, and decreases to 27.25 ± 5.82 g/dm3 for 28 days, which contributes to the formation of the immunosuppressive state at the 7th day of a calf life. Starting from 35th day, there is an increase in the concentration of total IgG due to seroconverting of its own antibodies by the body of calves. Immunization of cows-mothers against viral diarrhea, respiratory syncytial infection and parainfluenza-3 contributes to the formation of antigen-specific colostral immunity in calves in the first days of life, which is preserved in diagnostic titers during 63 days after birth.

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The results of the determination of the efficiency of the cleaning and disinfection protocol of pig farms contaminated by the porcine epidemic diarrhea virus are presented in this study. The research was conducted in the Scientific Research Center of Biosafety and Environmental Control AIC of the Dnipro State Agrarian and Economic University. The experimental part was carried out on the basis of a permanently infected pig breeding farm of the southern region of Ukraine. In order to determine the critical points, a selection of samples of washings/scraps from the surfaces of the pig farm’s premises and the objects of the environment was carried out before cleaning and disinfection and after 1 and 2 premises’ sanitation. A total of 204 tests were analyzed. Disinfection of the territory of pig farms and livestock premises was carried out in accordance with generally accepted methods. Before disinfection, a thorough mechanical cleaning of livestock premises was carried out, with subsequent irrigation of all surfaces with cold tap water. Disinfection of premises and the territory of the pig complex was carried out by the wet cleaning of surfaces with a solution of disinfectant based on glutaraldehyde after preparatory operations in the absence of animals. After disinfection the premises were additionally processed with Ca(OH)2 solution. Washes were obtained with a sterile swab from a surface of 10.0 cm2 by inserting a swab into a test tube with a sterile physiological solution. Scraps from the surfaces were obtained with a disposable sterile blades from the scalpel. The obtained material was placed in disposable sterile plastic 1.5–2.0 cm3 test tubes. The study of the presence of the PEDV was performed using a real-time polymerase chain reaction with the previous reverse transcription of RNA. It was established that the causative agent of PED in a permanently infected farm contaminates most of the production and auxiliary premises and objects of the environment. The one-time cleaning and disinfection protocol does not allow free the farm from the PEDV completely. Only two-time sanitation of premises and objects of the environment with the laboratory control of the efficiency of cleaning and disinfection contributes to the effective eradication of the PEDV.

The current question of today is the formation of effective immune protection in young pigs against infectious diseases, achieved by piglets vaccination in the first weeks of their life. It is known that one of the factors influencing the quality of vaccination is colostral antibodies, which are able to deactivate the vaccine antigen. Considering this, it is important to determine the duration of colostral immunity of piglets to antigens of the Aujeszky’s disease virus during active sows immunization. For this, was formed a group of sows of 2nd-3rd gestation periods with 25 animals in each. Sows were immunized parenterally against Aujeszky’s disease with the «Adivak» vaccine at a dose of 2 ml, by mass vaccination, three times per year. The level of specific antibodies to glycoproteins E (gE) and B (gB) was determined in the blood serum of piglets before sucking colostrum and every 7 days of life until 77 days from birth by enzyme-linked immunosorbent assay (ELISA). It was revealed that before consuming colostrum, piglets did not have specific antibodies to the antigens of the Aujeszky disease virus. From 7th till 70th days of life, all piglets had specific IgG to the antigens gB and gE of the Aujeszky disease virus, and by the seventy-seventh day, 29% of the animals were seronegative. Thus, newborn piglets before colostrum suckling do not have specific immune protection against the Aujeszky disease virus against the background of sow immunization. Consumption of colostrum by piglets promotes their formation of colostral immunity, specific to the antigens of the Aujeszky disease virus. The duration of colostral antibodies’ circulation specific to the antigens of the Aujeszky disease virus in the piglets peripheral blood is 70 days. On the seventy-seventh day from birth, the level of colostral immunoglobulins decreased sharply, which contributed to the appearance of seronegative animals and an increase in their sensitivity to the action of an epizootic strain of the virus.

The spreading of antibiotic resistance in the modern world results from the application of uncontrolled and excessively intensive antibiotics for treating human infectious diseases and their use as growth stimulants in animal farming. In some economically developed countries, restrictions on the use of antibiotics are already applied in order to prevent the generation of resistant strains of microorganisms. An essential component of such means is antibiotic-free strategies in animal farming. Recently, strategies based on the alternative to both antimicrobials and growth promoters have been proposed, including probiotics, prebiotics, synbiotics, enzymes, and organic acids. Short-chain fatty acids and monoglycerides based on them are considered a promising alternatives to antimicrobial agents for poultry farming. However, the effects of these compounds on innate immunity and cytokine production in the intestinal system remain undiscovered. The experiment was carried out using two groups of Cobb 500 cross broilers in the conditions of an industrial poultry farm. The broiler chickens of the research group were exposed to a monoglyceride mixture with С3, С4, С8–С10 fatty acids from 1 to 7 days of life and 16 to 22 days of life at a dose of 0.5 l of the mixture per ton of water. On the 31-st day of life, productive parameters were evaluated, and five birds were selected from each group. The fragments of the duodenum, caecum, and rectum with contents were taken from the bird. In the presented study, the content of interferon-α in the tissue of the small intestine of broiler chickens under the conditions of drinking monoglyceride was studied. To evaluate the beneficial effect of monoglyceride, the state of the microbiome and productive indicators were determined. The study showed that the monoglyceride induces a statistically significant increase in the content of enterococcus in the duodenum, suppresses the growth of staphylococcus, and increases the production of interferon-α. Moreover, average daily weight gain relative to controls was almost 2% greater in monoglyceride-treated chicks. Thus, preservation of the state of microbiota and moderate stimulation of interferon-α production can be essential components of the multidirectional protective effect of monoglycerides and fatty acids.