瘤胃保护胆碱对围产期高产奶牛产奶性能和血液生化指标的影响

Effect of Rumen-protected Choline on Milk Performances and Blood Biochemical Parameters of High Productive Periparturient Dairy Cows

为探究补充瘤胃保护胆碱(rumen-protected choline,RPC)对围产期高产奶牛产奶性能和血液生化指标的影响,试验选取44头健康的荷斯坦高产奶牛,按胎次、预产期、上一胎次产奶量等基本一致原则分为试验组和对照组,每组22头,饲喂相同基础日粮,试验组牛群补充20g/(d.头)的RPC。试验期内(产前14d～产后28d)分别监测两组产奶性能和血液生化指标。结果显示:奶牛产后第4周内的日均产奶量提高了2.31%(P>0.05),乳糖率下降了3.75%(P<0.05),而乳脂率、乳蛋白率、脂肪蛋白比及干物质比例分别提高了11.11%、5.56%、6.38%和2.94%,但差异均不显著(P>0.05);血浆中甘油三酯(TG)和β-羟丁酸(BHBA)含量在产犊当天、产后7d和产后14d这三个时间点的组间差异均不显著(P>0.05),但在数值上试验组TG和BHBA含量在产后7d和产后14d时均明显低于对照组。在本试验条件下,给围产期高产奶牛补充RPC可在一定程度上提高产奶量,改善乳品质及脂肪代谢,缓解能量负平衡,并降低肝脏脂肪沉积的危险。

This experiment was conducted to study the effect of rumen-protected choline （RPC） supplementation on milk performances and blood biochemical parameters of high productive periparturient dairy cows. Forty-four healthy Holstein cows with similar parity, expected calving date and milk yield were blocked into 22 pairs and then randomly allocated to either one of 2 treatments. Both groups received the same basal diet. The treatment group was supplemented with 20 g/d rumen-protected choline per cow. Treatments were applied from 2 wk before until 4 wk after calving, during which milk performances and blood biochemical parameters were investigated, respectively. The results showed that the average daily milk yield of the fourth week after calving increased by 2.31% （P〉0.05）. Lactose percentage decreased by 3.75% （P〈0.05） and milk fat percentage, milk protein percentage, （milk fat）/（milk protein） and dry matter percentage increased by 11.11%, 5.56%, 6.38% and 2.94% without significant difference （P〉0.05）, respectively. There were no significant difference （P〉0.05） on the content of both plasma triglyceride （TG） and β-hydroxybutyric acid （BHBA） between treatments on the time-point of calving, day 7 poscalving and day 14 postcalving, but the contents of plasma TG and BHBA of treatment group were apparently lower than the control. These results indicated that under the condition of this experiment RPC supplementation for high productive periparturient dairy cows could increase milk yield, improve milk quality and fat metabolism, relieve negative energy balance and reduce the risk of fat deposition in the liver.