Endosporin is used in veterinary for the prophylaxis and treatment of disbacteriosis, intestinal infections, festering wounds and postpartum pyoinflammatory complications in agricultural animals. The probiotic is based on two Bacillus strains which inhibit growth of a broad spectrum of pathogenic microorganisms and synthesise proteolytic enzymes and other biologically active secondary metabolites, particularly - polysaccharides. The activity of these two strains was supplementary. For the species identification of these strains, sequences of 16S rRNA genes and fatty acid content of cell walls were analysed. It was found that the both strains belong to B. velezensis. Limitations of application of 16S rRNA sequences for identification of closely related species are discussed in the paper. A method of 16S rRNA sequence profiling by polymorphic nucleotides was proposed. It was also shown that usefulness of Bacillus strains in probiotics is mostly based on their unique strain specific properties rather than on general species characteristics.