Submitted to: Proceedings of Mastitis in Dairy Cow
Publication Type: Proceedings
Publication Acceptance Date: 7/1/1998
Publication Date: N/A
Interpretive Summary: The main cause of mastitis is bacterial invasion and growth of bacteria within the udder. Migration of bacteria-killing white blood cells into mammary tissue provides the first line of defense against invading bacteria. Effectiveness of the white blood cells is dependent on specific recognition of the bacteria by antibodies which are subsequently recognized by the white blood cells. However, concentration of specific antibodies in mammary secretions is very low. Also, ingestion of fat and casein reduces the effectiveness of white blood cells. A great deal has been learned concerning migration of white blood cells into the mammary gland and antibody enhance killing. Several vaccines have shown limited but significant promise in increasing bacteria specific antibodies in lacteal secretions. However, a great deal of research needs to be done before an effective vaccine can be formulated.
Technical Abstract: Protection of the mammary gland is provided by lymphocytes which function in humoral and cell-mediated defense mechanisms, and by macrophages and neutrophils (PMN) which function as phagocytes. Migration of PMN into mammary tissue provides the first line of defense against bacteria that penetrate the streak canal. The incidence of udder infection and mastitis and clinical expression depend on stage of lactation and is usually highest at drying off and after calving. These periods are characterized by important physiological changes connected with metabolism and milk secretion. The humoral and cellular immune mechanisms that protect the mammary gland against infection by mastitis pathogens are summarized in this paper.