Study On The Influence Of Diptera Parasitic Insects On The Immunity Of Dairy Cows And Its Nerve-Endocrine Regulation

To study on the influence of the Inner Mongolia diptera parasitic insects on the immunity of the Holstein dairy cows and its nerve-endocrine regulation, 12 healthy Holstein cows with similar lactation ability and the same reproductive timing were studied from June to October, 6 days was as an experiment period in every month. During the trial period, the attack times of the diptera parasitic insects and cows behavior were reCorded and studied for 4 hours every day. And the CD3, CD4, CD8, CD21 active T, B lymphocyte and subpopulations percentages of peripheral blood were counted with flow cytometry at the same time. And the AdrenoCorticotropic hormone (ACTH), Cortisol (Cor), Growth hormone (GH), Prolactin (PRL) and Norepinephrine (NE) were checked with the radio immune and ELISA method. The results showed: (1) the attack frequency of the diptera parasitic insects to the cows was significantly related to the Changes in temperature. (2) as the attack frequency increased CD3 +T cell%, CD4 + T cell %, CD21 + B cell % and CD4+/CD8+ of the peripheral blood was decreased significantly, C3bRR/ICR has a downward trend and CD8+T cell% increased. The results indicate that the cell immunity, humoral immunity and the red cell immunity were depressed and the immune function decreased those days. (3) The depression of the immunity of the cows caused by the diptera parasitic insects primarily was regulated by the combination of the Hypothalamo-pitutary-adren (HPA) and sympathetic nervous system (SNS) which resulted in the increase of the ACTH, Cor and NE in the peripheral blood. And as the attack continued the activation HPA was inhibited, the ACTH and Cor decreased slowly, while the NE did not change. As the SNS played the most important role in the regulation, the NE of the peripheral increased.