The development of the small intestine walls membranes in fetuses and in calves of the Kostromskaya cow breed during the first day of their birth

A morphometric characteristic of the duodenal, jejunum and ileum wall membranes in 9-month fetuses and one-day-calves of the Kostromskaya cow breed is presented, it having allowed to identify both regular and differentiating traits which could be revealed by the following indicators: dynamics of the membranes (mucosa, submucous, muscular and serosal) thickness and their structural components increase; the height of the mucosal folds; the height and width of the villi; the depth and breadth of the intestinal crypts; duodenal glands position etc. Small-intestinal mucosa undergoes intensive adaptive modification in one-day-old calves caused by their nutrition change.