Postnatal morphogenesis of the right ruminal vein's tunica media of the cattle stomach

The objective was to study postnatal morpho- genesis of the tunica media of right ruminal vein of the stomach of cattle. The objectives of the study were to reveal the peculiarities of structural trans- formations of the tunica media of the right ruminalvein and morphometric features of its myocytes in age aspect. The material for the study was taken from 35 stomachs of cattle of black-and-white breed of seven age groups: newborns (1 day), 30 days, 3 months, 6 months, 18 months, 3 years, 8- 10 years of age. It was found out that providing ad- equate blood flow, the vessel wall develops in full accordance with abrupt development of the rumen. Characteristic feature was the increase in the thick- ness of the tunica media mainly due to the increase in the number of layers of smooth muscle cells to 18 months of age. The share of the tunica media in percentage terms increases from 24.27 % in new- borns (1 day) to 41.32 % of the total vascular wall thickness in animal aged 18 months...