Comparative histomorphometry of postnatal skin development of heifers of 4 breeds of base and initial genotypes

The total thickness of the skin heifers four groups increased from 3 to 18 months postnatal ontogenesis, depending on breed, by 16–27 %. In base and original genotype breeds, different periods completion growth were established. all heifers, there fundamental differences in dynamics outer integument. epidermal layer reached maximum values early ontogeny heifers. layers dermis with age, 33–43 % – papillary 9–24 reticular. ontogenesis groups, noticeable increase (more than 50 %) occurred age period 3–6 months, changes reticular depended breed Structural transformations its internal organization accompanied development ratio changed within 5–8 %, breed. reliable epidermis (together subcutaneous base) was manifested, as well parameters papillary/reticular dermis. dependence barrier year seasonal breeds indicate probable corrective effect environmental factors morphology difference manifestations adaptation.