MORPHOLOGICAL AND FUNCTIONAL CHARACTERISTICS OF MAMMARY GLAND IN COWS WITH SUBCLINICAL MASTITIS

Abstract

This paper presents morphological and functional characteristics of structural organization of mammary gland in cows with subclinical mastitis based on anatomical, histological, and up-to-date electronic microscopy study. It was found that pathology development in the cow mammary gland is associated with abundant effusion of serous-catarrhal effluent into alveoli. The gland is comprised of excretory ducts and terminal secretory parts; alveoli are polymorphous and have different size. The walls of terminal secretory parts of the gland are made of one layer of secretory epithelium and myoepithelial cells. Lactocytes vacuolated sporadically and separated from alveolar membrane. Alveolar septa are expanded due to spongiose connective tissue and blood capillaries. Ultrafine structure of mammary gland in cows with subclinical mastitis demonstrates wider microcirculatory passes in the organ’s parenchyma, and desquamation of alveoli sectretory cells. Corruption of alveolar lining occurs sporadically. Electronic microscopy shows that inflammatory cellular infiltrates are mainly consist of sparse polynuclear (segmented nuclei) cells, lymphoid, macrophages, and plasmatic cells. Characteristic plasmatic and mast cells were detected, however in the state of dystrophication. Natural death (apoptosis) is observed among epithelial cells containing secretory granules. Lymphocyte and leukocyte count increases in the inflammatory infiltrate due to the onset of pathology process in mammary gland tissue.