The conditionally pathogenic microflora causes the outbreak of non-contagious diseases of agricultural animals, this microflora is present in healthy organism and does not cause infectious diseases. It usually concerns the diseases of respiratory system and intestinal tract. On the basis of decrease of general organism resistance in consequence of inappropriate feeding or bad keeping conditions and handling of animals conditionally pathogenic organisms are becoming pathogenic that can cause clinically expressed course of disease. The application of antibiotic therapy is aiming at depression of pathogenic bacteria activity. Nowadays there is large quantity of antibacterial medicinal products belonging to different pharmacological groups with broad and narrow spectrum of action. Despite this fact, the application of this or that antibiotic does not have desired medicinal effect. It is the result of progressive development of antibiotic resistance among microorganisms that are able to cause infectious diseases.

That is why the selection of antimicrobial medicinal product for the treatment of bacterial infections should be based on the sensitivity of causal organism or causal organisms of disease to antibiotics. The most simple and available determination method of antimicrobial sensitivity of microorganisms is the method of agar diffusion with application of standard disks with antibiotics. This method determines whether animal microflora of sick animal is sensitive to the effect of this or that antimicrobial medicinal product.

This article presents the results of the determination of conditionally pathogenic microflora sensitivity of sick animals with non-contagious diseases of internal organs of piglets and calves (pneumonia of piglets, bronchial pneumonia and gastroenteritis of calves) that belonged to agricultural enterprises of different form of property in Lviv region. Enterococcus faecalis, Streptococcus suis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Diplococcus pneumoniae were extracted and identified as conditionally pathogenic bacteria. The obtained results showed that causal organisms showed the resistance to some antibacterial substances. The sensitivity level of microflora to this or that antibiotic depended on its specific composition and was different for each animal species at different diseases. It shows that the development of antibiotic resistance of microorganisms depends on genetic mechanism of each antibiotic and acquirement time and resistibility level are different for separate antimicrobial agent and for specific microorganism strain.

The monitoring of organism sensitivity, main causal organisms of non-contagious diseases of bacterial etiology of young animals of cattle and pigs will help the veterinarian to select the effective mean of etiotropic therapy. The test of antimicrobial sensitivity of microbial population of animals conducted on the regular basis will facilitate the rational application of antimicrobial medicinal products that will prevent the appearance and distribution of antibiotic resistant microorganism strains and will increase the efficacy of antibiotic therapy under conditions of farm and agricultural enterprise.

The regular monitoring over the dynamics of antibiotic resistance of microorganisms, causal organisms of non-contagious diseases of bacterial etiology of agricultural animals will facilitate the development of certain measures of risk management connected with the development of antibiotic resistance in separately taken husbandry, region and the whole country.

Key words: non-contagious diseases, piglets, calves, antibiotics, microorganisms, antibiotic resistance.