Feeding high proportions of barley grain in a total mixed ration perturbs diurnal patterns of plasma metabolites in lactating dairy cows
Feeding high proportions of barley grain in a total mixed ration perturbs diurnal patterns of plasma metabolites in lactating dairy cows
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DOI：
10.3168/jds.2008-1465
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发表时间：
2009-03-01
影响因子：
3.5
通讯作者：
Dunn, S. M.
中科院分区：
文献类型：
--
作者：
Ametaj, B. N.;Emmanuel, D. G. V.;Dunn, S. M.
本研究的目的是评估在全混合日粮（TMR）中饲喂大麦粒比例增加对高产奶牛血浆代谢物昼夜波动的影响。8头泌乳早期至中期（产奶60至140 d）的经产荷斯坦奶牛被分配到一个双4 × 4拉丁方试验设计。每个试验期持续21 d，前11 d用于饮食适应。奶牛饲喂TMR每天一次在0800小时不含大麦颗粒（对照饮食），或15，30，和45%（干物质基础）大麦颗粒以及大麦青贮饲料。在每个时期的最后一天从尾静脉收集血样，0 h）以及早晨喂食后2、4、6、8、10和12 h。测定血浆中葡萄糖、非酯化脂肪酸（NEFA）、β-羟基丁酸、胆固醇和乳酸的浓度。这项研究的结果表明，喂养比例增加的大麦谷物影响血浆中的葡萄糖和乳酸的浓度，更大的血浆葡萄糖和乳酸的奶牛喂养的最高量的谷物，但是，在饮食中的谷物量没有影响昼夜模式的血浆葡萄糖。此外，血浆中NEFA的浓度在饲喂较高谷物饲料的奶牛中更高，并且在早餐后的几个小时内比当天晚些时候更高。饮食中谷物的量与较低的血浆β-羟丁酸有关，尤其是在早餐后增加。有趣的是，饲喂最多大麦的奶牛血浆胆固醇最低，并且在白天降低。总之，伴随着增加的葡萄糖，乳酸盐，NEFA以及降低血浆胆固醇的奶牛喂高比例的大麦颗粒表明，高列入饮食中的大麦颗粒发挥了作用，在泌乳奶牛的血浆代谢物的昼夜模式。然而，需要进一步研究以了解这些代谢变化对奶牛长期健康和生产力的影响。
The aim of this study was to evaluate effects of feeding increasing proportions of barley grain in a total mixed ration (TMR) on diurnal plasma metabolite fluctuations in high-producing dairy cows. Eight early-to mid-lactation (60 to 140 d in milk) primiparous Holstein cows were assigned to a double 4 x 4 Latin square experimental design. Each experimental period lasted 21 d with the first 11 d used for diet adaptation. Cows were fed a TMR once daily at 0800 h containing no barley grain (control diet), or 15, 30, and 45% (dry matter basis) barley grain as well as barley silage. Blood samples were collected from the tail vein on the last day of each period shortly before (i.e., 0 h) and at 2, 4, 6, 8, 10, and 12 h after the morning feeding. Concentrations of glucose, nonesterified fatty acids (NEFA), beta-hydroxybutyric acid, cholesterol, and lactate in plasma were measured. Results of this study showed that feeding increasing proportions of barley grain affected concentrations of glucose and lactate in plasma with greater plasma glucose and lactate in cows fed the highest amount of grain; however, the amount of grain in the diet did not have an effect on diurnal patterns of plasma glucose. Additionally, the concentration of NEFA in plasma was greater in cows fed the higher grain diets and was greater in the hours following the morning meal than later in the day. The amount of grain in the diet was associated with lower plasma beta-hydroxybutyric acid, which increased particularly after the morning meal. Interestingly, cows fed the most barley grain had the lowest plasma cholesterol and this decreased during the day. In conclusion, the concomitant increase of glucose, lactate, and NEFA as well as the decrease of plasma cholesterol in cows fed high proportions of barley grain suggest that high inclusion of barley grain in the diet played a role in the diurnal patterns of plasma metabolites in lactating dairy cows. However, further research is warranted to understand involvement of these metabolic changes on the long-term health and productivity of dairy cows.