The escherichiosis disease at current stage of livestock development is considered to be the most common infectious disease among other infectious diseases, caused by Enterobacteriaceae bacteria. Among the prevention methods of escherichia coli there is a specific prophylaxis with the use of vaccine and antibiotics. Vaccination does not always prevent the colibacteriosis disease of calves due to a number of reasons: bacterial vaccines do not have a complete set of serovars E. coli, there is often loss of immunogenicity of the vaccine along with its pathogenicity.

According to retrospective analysis results, the incidence of calves in different regions of Ukraine varies considerably. It is related to the reorganization of inter-district laboratories and their service area distance increase. Under these complicated conditions not all cases of calves disease were the subject for registration, and the material from sick and dead calves was not always sent for bacteriological examination.

The disease pathogenesis development showed that the esherichia were spread to different systems of the body and intensively multiplied. They penetrated into mucous membrane of small intestine, excreted exo- and endotoxins, which caused inflammation and diarrhea. Body dehydration and intoxication ended with lethality.

Clinical signs of enteritic and enterotoxemic forms of colibacteriosis were characterized by diarrhea, body temperature increase by 0,5 - 1 °С, increased thirst, intoxication, dehydration, extenuation and death of calves.

The enteric and enterotoxic form of calves colibacteriosis did not differ pathologically and anatomically. An animal used to die being six to seven days old. The corpses of these calves were thin, the tail and pelvic wool was contaminated with liquid faeces. Eyeballs were deeply dropped into the eye orbits, subcutaneous tissue and skeletal muscle were dry (a sign of dehydration). Abomasum and small intestine had signs of intense catarrhal inflammation, and some small intestines loops had hemorrhagic catarrh. Grain dystrophy in the myocardium, liver and kidneys developed more intensively, and as a result of heart failure, these body parts developed haemostasia. The sick calves, born in winter and spring period, had keratinized cone-shaped papillae on the edge of reticulum and omasum, thus indicating a deficiency of vitamin A in pregnant cows. Calves, born from such cows, are prone to diseases, including colibacteriosis.

In the process of studying the pathological material from calves' corpses there were detected short, polymorphic, gram-negative sticks without spores in preparations from blood and organs, painted by Gram method. To receive pure culture from the experimental material the inoculations were carried out on MPB, MPA, Endo. During the course of research different E.coli serovars were developed from different farms, namely O₁₀, O₁₁₅, O₁₂₇. Selected E.coli cultures were tested for sensitivity to 30 antibacterial drugs. The E.coli sensitivity to antibacterial drugs was determined by the size of the growth inhibition zone. The studied E.coli cultures did not have high resistance to any of the 30 antibiotics. But weak sensitivity was detected to cefazolin, erythromycin, novobiocin, lincomycin, norfloxacin, and moderate sensitivity to rest.

The basis for calves escherichiosis prevention is the vaccination of cows, which in most cases turns out to be ineffective. Evidence for this is that the calves morbidity and mortality from colibacteriosis remains high, since the presence of a significant number of E.coli serovars (164) makes it impossible to create an effective vaccine. Vaccination is most effective when the vaccine is prepared from local strains of E. coli of the given farm, separately of the given household.

The cultured E.coli vaccine was prepared as a microbial cells suspension of the serovar, excreted from the pathological material of the calves of the individual farm. The received suspension of the pathogen was inactivated, checked for sterility. The propolis extract was added as an adjuvant to the prepared inactivated suspension.

In general, wide vaccine trial was carried out on 662 cows with long pregnancy period in 3 farms. Experimental data of propolis-escherichia vaccine showed its high (85%) immunogenic activity. It was recorded that inactivated propolis-escherichiosis vaccine, made from local pathogenic E. coli serovars and administered twice to long pregnancy period cows at intervals of 20 days, prevents the colibacteriosis disease of calves.

Key words: colibacteriosis, E. coli, serovars, exotoxins, endotoxins, diagnosis, prophylaxis, propolis, vaccine.