In the conditions of modern man-caused pollution of the environment, environmental problems, as well as improving the quality of livestock products and their food safety, are important and relevant issues today. The study aimed to investigate the effect of the “Metisevit Plus” feed additive on bull blood's morphological and biochemical parameters under lead-cadmium loading conditions. The research was conducted based on the agricultural private enterprise “Ukraine” of Dubrovytsia district of Rivne region on 12 bulls of six months of age, Ukrainian black-and-white dairy breed, which was formed into two groups of 6 animals each. The bulls of the control group were on a standard diet. The bulls of the experimental group were fed the feed additive “Metisevit Plus” at a dose of 0.5 g/kg of feed. This farm has a high content of lead and cadmium in feed. According to the results of experimental studies, it was found that the feed additive “Metisevit Plus” is effective under lead-cadmium load in bulls. Administration of this feed additive to experimental animals helps restore their suppressed hematopoietic function; the number of erythrocytes and hemoglobin in their blood increased by 25.3 and 19.4 %, and the number of leukocytes decreased by 12.4 %, respectively. Metisevit Plus feed additive also enhanced the functional state and protein-synthesizing function of the liver of bulls under artificial conditions. When feeding the feed additive “Metisevit Plus”, a decrease in the activity of both alanine aminotransferase and aspartate aminotransferase in the serum of bulls of the experimental group was found. On day 40 of the experiment, it was found that the activity of alanine and aspartate aminotransferase in the serum of bulls of the experimental group fluctuated within physiological values. When a “Metisevit-Plus” feed additive is added to the diet, there is a tendency to increase the total protein level in bulls of the experimental group. In the study of the albumin level in the blood of bulls of the experimental group, its probable increase was found starting from the 10th day of the experiment. On the 30th and 40th day of the experiment, the albumin level in the blood of bulls in the experimental group was the highest, whereas compared to the control group, it increased by 15.4 and 17.0 %, respectively. Our studies confirm the feasibility of using the feed additive “Metisevit Plus” to prevent lead-cadmium toxicosis.

The problem of treatment of acute digestive disorders with signs of diarrhea in calves remains relevant and important, as there are no sufficiently effective drugs, including antimicrobial effects. The low effectiveness of antibiotics and other chemotherapeutic agents and therapies in the vast majority of farms dictates the need to find new drugs. The purpose of our work was to study the significance of opportunistic microorganisms in the etiology of calving diarrhea. The research was conducted at farms of Lviv and Volyn regions. The incidence of newborn calves with acute digestive disorders with signs of diarrhea ranged from 36.8 to 100%, and mortality ranged from 17.4 to 30.8%. Bacteriological study was subjected to patmaterial from 20 dead calves at the age of 1–7 days. In this case, 88 cultures have been isolated from the internal organs, mesenteric lymph nodes, bone marrow, brain, walls and intestines. According to the culture – morphological properties, the cultures were classified into the following species: Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Diplococcus capsulatus, Clostridium perfringens. In the bacteriological study of all microorganisms isolated - Diplococcus capsulatus 29.5%, Escherichia coli 30.7%, Pseudomonas aeruginosa 19.3%, Clostridium perfringens 11.4%, Proteus vulgaris 9.1%. Out of the 14 households, the causes of the disease of calves with acute gastrointestinal disorders in 35.7% of cases were certain opportunistic pathogens (Escherichia coli, Diplococcus capsulatus, Pseudomonas aeruginosa, Clostridium perfringens, Proteus vulgaris). In most farms (64.28%), the disease was caused by association (2, 3 and more) types of microbes. The pathogenic properties of the isolated cultures were tested on white mice. In determining the pathogenicity of isolated cultures from dead calves on white mice, the most pathogenic were microorganisms of the species Pseudomonas aeruginosa. Experimental mice (42.0%) died within 6–12 hours after infection. Highly pathogenic were mixed cultures of E. coli, diplococci, Pseudomonas aeruginosa, which killed 58.0% of infected mice 24–48 hours after infection. This indicates an increase in the pathogenic properties of microorganisms in the association. In order not to allow the passage of conditionally pathogenic microflora, it is necessary to adhere to the sanitary regime in dispensaries and maternity departments, and the terms of disinfection with variable sectional retention.

The article deals with the data on the influence of probiotic preparation BPS-44 and 2% yeast Saccharomyces cerеvisiae on the histostructure of tissues of the cloacal sac (bursa of Fabricius) of broiler chickens. The conducted histological researches have shown that in chickens of the control group at the end of the experiment in the cloacal sac were revealed intraepithelial microcystic cavities, but in the medullary substance of the lymph nodes, necrotic changes are recorded and glandular structures are formed, indicating an insufficient level of lymphopoiesis. The use of these probiotic preparations to broilers from the experimental groups during the period of their growth in the ration caused a normalizing effect on the morphostructure of the cloacal sac and, in particular, on the action of 2% yeast Saccharomyces cerеvisiae. It is evidenced by the absence of the formation of microscystic cavities in the epithelial layer of the cloacal sac (signs of slowing down the processes of age involution). In this case, the lymph nodes are numerical, the division into cortical and medullar substance is clear, they were densely populated with lymphoid elements, indicating the possibility of forming an adequate immune response in the poultry of this group.

Pasteurleozy is a factor disease. The manifestation of pathogenic action of pasteurals occurs under conditions of influence on a susceptible organism of a number of negative factors, which are conventionally divided into contributing and adversarial. In the etiology of pasteurial infection, they play a decisive role. The problem of the struggle against rabbit pasterelosis in our country is paid insufficient attention. The analysis of the documents of the state veterinary report gives grounds to assert that the tension of the epizootic situation with regard to rabies pasteurse in the country remains unexplored. So, in official data on outbreaks of rabies pasterelosis during the last 10 years there are separate reports, from which it is impossible to make a comprehensive assessment of the epizootic process of this infection in Ukraine. There is no data on the characteristics of circulating serotypes of Pasteurella multocida in rabbit farms. There are only brief information about the spread of the disease in the rabbits in certain regions, in particular, the Luhansk, Donetsk and Zaporizhzhya oblasts. These reports indicate a poor condition for the maintenance of rabbits and an insufficient level of antiepizootic measures, which, according to the authors, is the main reason for the spread of pasteurellosis. Given these data, it can be assumed that pasteurellosis is a rather common disease of rabbits, not only in the east of Ukraine, but also in the whole country. In the system of antiepirosis measures of rabies pasteurellosis, the leading role is given to active immunization of the susceptible animal population. The article presents the results of the analysis of the domestic and world market of veterinary immunobiological means for the specific prevention of this infection. It is shown that only one vaccine against pasterelosis of rabbits of foreign production and no domestic vaccine has been registered in Ukraine. A comparative analysis of the main components of foreign vaccines and vaccines developed by our scientists was carried out. The most common inactivator in pasteurial vaccines is formaldehyde, despite the fact that it destroys the capsule, which plays an important role in the formation of the immune response and immunity tension. All foreign vaccines as a preservative contain thiomersal – an organic derivative of mercury. As an adjuvant mineral oil and aluminum hydroxide are used, both substances are reactogenic for the rabbit organism. It has been shown that the immunogenic component of pasteurial vaccines includes several serotypes of P. multocida.

The morbidity of newborn calves caused by enterotoxigenic staphylococci is associated with an increase in staphylococcal processes that are localized in the lizard of the cows and the carrier of the pathogen. Such cows, often with colostrum, transmit the pathogen and its toxins to newborn calves. According to the results of bacteriological studies, in the subclinical form of the mastitis with secretion of the dementia of the cows, Staph. aureus, staph. intermedius, staph. epidermidis, E. coli, Ps. auruginosa, etc., in pure culture, but in most cases, in association with other microorganisms. Staphylococcuses isolated in 25 strains were tested for enterotoxicity. From the strains examined, they produced: three strains of enterotoxin B and five strains enterotoxins B and C. The disease of the cows by staphylococcal infection of the udder influenced the fetal development of the fetus. From cows suffering from mastitis, calves were born weak and 1–2.5 kg live weight lower than from healthy cows. Calves (16 heads) who received colostrum from mothers with staphylococcal infection of the udder in association with other microorganisms, in fourteen cases were ill with signs of disorders of the gastrointestinal tract. Among calves born from cows suffering from mastitis, but who received colostrum from healthy cows, two of them fell from ten heads. In calves of both groups, the activity of cellular elements was determined by opsonophagocytic response. In the experimental group, where the calves received colostrum, were infected with staphylococci, the intensity of phagocytosis in all study periods was lower (from 0.4 to 1.9) compared with the control group calves. Quality of colostrum of cows also affected the activity of phagocytosis prplodu. In the experimental group, the activity of phagocytosis was throughout the experiment at one level – 33, and in calves that received colostrum from healthy cows, activity increased (after one day – 37, and for the second and third day – 40). Studies have shown that colostrum infected with enterotoxigenic staphylococci, especially in association, is dangerous for newborn calves. It causes them diarrhea and often leads to death. We have confirmed the etiological connection between cows disease with mastitis of staphylococcal etiology and enterocolitis of newborn calves.