奶牛乳腺的防御机制与乳腺炎病理学

乳头管的结构和内衬的角质蛋白是乳腺抵御微生物侵入的物理性屏障,角蛋白中的低级脂肪酸、阳离子蛋白质对侵入的病原微生物具有抗性;环境性致病菌是引起机体免疫应答的主要因子,巨噬细胞、单核细胞、中性粒细胞和淋巴细胞之间的相互协调组成了自然的免疫系统,它们通过分泌细胞因子、抗体和吞噬作用等活动来灭杀、清除侵入机体的病原体;乳中的可溶性因子具有免疫调节作用,对细菌的结构具有破坏性;妊娠期及围产期奶牛由于内分泌的变化而导致免疫抑制,结果造成临床型和亚临床型乳腺炎的发病率相对较高;牛奶体细胞计数对亚临床型乳腺炎的监控具有参考性。

The Defence Mechanism of Mammary Gland and Pathology of Mastitis in Dairy Cow

The construction of the teat canal and lining with keratin are physical barricade for mammary gland to resist invasion by pathogens.The fatty acid and cationic protein in keratin have resistance to invasive pathogenic microorganism.Environmental pathogens is major factors to cause immune response.Macrophages,mononuclear cell,PMN and lymphocytes intercoordinate and compose innate immune system.They eliminate and kill pathogens by excreting cytokines,excreting antibodies and phagocytosis and so on.Soluble factors of milk possess immunological regulation effect and destructiveness to construction of bacterium.Gestation period and perinatal period induce immune suppression owing to the change of internal hormone,the consequence causes increase in incidence of clinical and subclinical mastitis.Somatic cell count of milk can act as reference for monitoring subclinical mastitis.