Institute of Animal Breeding and Genetics, Justus Liebig University, 35390 Giessen, Germany.
Educational and Research Centre for Animal Husbandry, Hofgut Neumuehle, 67728 Muenchweiler an der Alsenz, Germany.
J Dairy Sci. 2023 Oct;106(10):7281-7294. doi: 10.3168/jds.2022-22890. Epub 2023 Jul 26.
Heat stress (HS) impairs productivity, health, and welfare in dairy cows, and additionally causes metabolic changes. Hence, specific metabolites could be used as HS biomarkers. Consequently, the aim of the present study was to compare blood metabolite concentrations of German Holstein dairy cows and of their female calves suffering from high temperature-humidity index (THI) during late gestation (cows) or during their first week of life (calves) or not. According to the mean daily THI (mTHI) at the day before blood sampling, animals were classified into 2 groups: high mTHI ≥60 (hmTHI) and low mTHI <60 (lmTHI). To perform a standard cross-sectional 2-group study, cow groups (n = 48) and calf groups (n = 47) were compared separately. Differences in metabolite concentrations between hmTHI and lmTHI animals were inferred based on a targeted metabolomics approach. In the first step, processed metabolomics data were evaluated by multivariate data analysis techniques, and were visualized using the web-based platform MetaboAnalyst V5.0. The most important metabolites with pronounced differences between groups were further analyzed in a second step using linear mixed models. We identified 9 thermally sensitive metabolites for the cows [dodecanedioic acid; 3-indolepropionic acid; sarcosine; triglycerides (14:0_34:0), (16:0_38:7), (18:0_32:1), and (18:0_36:2); phosphatidylcholine aa C38:1; and lysophosphatidylcholine a C20:3] and for the calves [phosphatidylcholines aa C38:1, ae C38:3, ae C36:0, and ae C36:2; cholesteryl esters (17:1) and (20:3); sphingomyelins C18:0 and C18:1; and p-cresol sulfate], most of them related to lipid metabolism. Apart from 2 metabolites (3-indolepropionic acid and sarcosine) in cows, the metabolite plasma concentrations were lower in hmTHI than in lmTHI groups. In our heat-stressed dry cows, results indicate an altered lipid metabolism compared with lactating heat-stressed cows, due to the missing antilipolytic effect of HS. The results also indicate alterations in lipid metabolism of calves due to high mTHI in the first week of life. From a cross-generation perspective, high mTHI directly before calving seems to reduce colostrum quality, with detrimental effects on metabolite concentrations in offspring.
热应激（HS）会降低奶牛的生产力、健康和福利，并导致代谢变化。因此，特定的代谢物可以用作 HS 的生物标志物。因此，本研究的目的是比较患有高温高湿指数（THI）的德国荷斯坦奶牛及其雌性犊牛在妊娠后期（奶牛）或出生后第一周（犊牛）或未患病时的血液代谢物浓度。根据采血前一天的平均日 THI（mTHI），将动物分为 2 组：高 mTHI≥60（hmTHI）和低 mTHI<60（lmTHI）。为了进行标准的横截面 2 组研究，分别比较了奶牛组（n=48）和犊牛组（n=47）。基于靶向代谢组学方法推断 hmTHI 和 lmTHI 动物之间代谢物浓度的差异。在第一步中，使用多元数据分析技术评估处理后的代谢组学数据，并使用基于网络的 MetaboAnalyst V5.0 平台进行可视化。在第二步中，使用线性混合模型进一步分析具有明显组间差异的最重要代谢物。我们确定了 9 种对奶牛具有热敏感性的代谢物[十二烷二酸；3-吲哚丙酸；肌氨酸；甘油三酯（14:0_34:0）、（16:0_38:7）、（18:0_32:1）和（18:0_36:2）；磷脂酰胆碱 aa C38:1；和溶血磷脂酰胆碱 a C20:3]和对犊牛具有热敏感性的代谢物[磷脂酰胆碱 aa C38:1、ae C38:3、ae C36:0 和 ae C36:2；胆固醇酯（17:1）和（20:3）；神经鞘磷脂 C18:0 和 C18:1；和 p- 对甲酚硫酸盐]，其中大多数与脂代谢有关。除了奶牛中的 2 种代谢物（3-吲哚丙酸和肌氨酸）外，hmTHI 组的代谢物血浆浓度低于 lmTHI 组。在我们的热应激干奶牛中，与泌乳热应激奶牛相比，由于 HS 缺乏抗脂解作用，结果表明脂代谢发生了改变。结果还表明，由于生命第一周的高 mTHI，犊牛的脂代谢发生了改变。从跨代的角度来看，分娩前的高 mTHI 似乎会降低初乳质量，并对后代的代谢物浓度产生不利影响。
