Scientific justification of effective pre-vention of endemic diseases in productive animals, taking into account the biogeo-chemical characteristics of the regions, is an urgent problem of modern veterinary and animal science. Therefore, the aim of the assay was to study the dynamics of immuno-morphological development of gobies con-tained in the iodine-seleno deficiency region with administation of trepel, «Polystim», iodomidol and selenopiran. Experiments were carried out on 3 groups of similar bulls for 10 heads each. The studied animals were kept in individual houses and group pavilions using adaptive technology from 2 to 150 days, then up to 540 days (the duration of the experiments) – in industrial farms. Animals of 1 group served as control; groups 2 and 3 were used for 2, 31, 151, 361 days of life, respectively, trepel with «Polystim» and iodomidol with selenopyran according to the schemes devel-oped by us. U 2-, 30-, 60-, 150-, 360-, 390-, 540-diurnal animals of these groups were studied the dynamics of the clinical and physiological state, the content of immuno -, thyroglobulins in the blood; in bulls killed at the age of 30, 150, 540 days-the micromor-phology of the thyroid and thymus glands by standard methods. The digital data obtained in the experiments were subjected to bio-metric analysis (Statistica for Windows and Microsoft Excel-2016). In the simulated studies, the immune-morphological expediency of complex ad-ministration to bulls at the beginning of the growing, rearing and fattening periods of the tested bioactive substances was proved, tak-ing into account local iodine and selenium insufficiency. If the immunotrofic effect on the body of trepel with «Polystim» (group 2), and iodomidol with selenopyran (group 3) was almost identical, then the thyriotrofic effect is much more pronounced in animals of group 3
