Effects of the lactation on cellular energy supply and aging processes in dairy cows

泌乳后的高产奶量直接导致奶牛代谢活动增加，从而增加脂肪组织库的动员。代谢应激伴随着代谢和感染疾病以及生育功能障碍的发病率增加。在泌乳早期，参与衰老过程的代谢率的提高可能对奶牛寿命和生产周期的持续缩短很重要。在泌乳早期，脂肪组织的动员改变了脂肪库的总脂肪量，导致脂肪细胞变小，细胞数量减少，程序性细胞死亡（细胞凋亡）。是否优先细胞老化-由表观遗传过程控制-减少能量供应或两者导致细胞凋亡增加尚不清楚。因此，将研究直接参与代谢和能量过程的器官（乳腺、肝脏、脂肪组织），因为它们的细胞能量供应和表观遗传（衰老）过程。通过比较经产奶牛和经产奶牛，将确定通过产奶量的增加对奶牛高产的影响，以及增加生产时间和强度。

The high milk yield directly after lactation results in an increased metabolic activity in dairy cows leading to increased mobilization of adipose tissue depots. The metabolic stress is accompanied by increased incidences of metabolic and infection diseases as well as fertility dysfunctions. During early lactation the enhanced metabolic rate involved in aging processes, is probably important for ongoing shortened longevity and production period of dairy cows. Total fat mass of the fat depots is changed through mobilization of adipose tissue during early lactation, leading to smaller adipocytes and a decline of the amount of cells, the programmed cell death (apoptosis). Whether preferentially cell ageing -controlled by epigenetic processes- reduced energy supply or both leads to increased apoptosis is not known. Therefore, organs directly involved in metabolic and energetic processes (mammary gland, liver, adipose tissue) will be investigated due to their cellular energy supply and epigenetic (aging) processes. Comparing primiparous and pluriparous cows, the impact of high yielding, effected through milk synthesis, in dairy cows with increased production time and intensity will be identified.