能量平衡对围产期奶牛泌乳和干物质摄入量及机体代谢的影响

Effect of Energy Balance on Milk Yield,Dry Matter Intake,and Metabolism of Dairy Cows in Transition Period

为了阐明不同能量平衡状况的围产期奶牛泌乳量、干物质摄入的变化及其机体代谢调节作用。在某一集约化牛场选取胎次、年龄相近的奶牛,分为高血糖组(H)和低血糖组(L),每组各15头。在产前21、14、7d和分娩当天,产后7、14、21d,分别记录奶牛围产期干物质摄入量(DMI)、泌乳量(MY),并测定血浆血糖(Glu)、游离脂肪酸(NEFA)、β-羟丁酸(BHBA)、胰岛素(Ins)、胰高血糖素(Gn)、瘦蛋白(Lp)、皮质醇(Cor)的浓度。结果显示,试验奶牛产后泌乳量和干物质摄入量均增加,但是产后能量负平衡发生率高于产前,产后21d达最高;两组产后血浆Glu水平均降低,血浆NEFA和BHBA升高,L组血浆NEFA和BH-BA水平高于H组(P<0.05);H组血浆Ins与Lp水平高于L组(P<0.05),血浆Gn与Cor水平低于L组(P<0.05)。围产期不同能量平衡状态的奶牛机体能量代谢发生了各自适应性的变化。血浆低水平Ins、Lp和高水平Cor在缓解能量负平衡方面发挥了重要作用。

To ascertain changes of milk yield, dry matter intake, and its metabolic regulation in condition of different energy balance in transition period, thirty dairy cows chosen （similar years and parities） in a dairy farm were divided into high blood glucose group （H） and low blood glucose group （L） respectively in transition period, fifteen cows per group. At days of 21, 14, 7 before calving, parturition, 21, 14, 7 after calving, dry matter intake, milk yield were investigated, and the concentrations of plasma Glu, NEFA, BHBA, Ins, Gn, Lp and Cor were measured. Results indicated that the milk yield and dry matter intake of tested cows increased after calving, but incidence of NEB was higher after calving than before calving, was the highest at day 21 after calving; level of plasma Glu deceased, and the plasma NEFA and BHBA increased in two groups, but the level of plasma NEFA and BHBA was higher in group L than in group H （P 〈0.05）, the level of plasma Ins and Lp was higher in group H than in group L （P 〈0.05）, and the plasma Gn and Cot were lower in group H than in group L （P 〈0. 05）. Conclusions obtained that the adaparive metabolic changes occur in different status of energy balance in transition period. Low level of plasma Ins, Leptin and high level of plasma Cor play an important role in relief of begative energy nalance in transtion period.