The present study aimed to investigate blood biomarkers encompassing the metabolic status of Simmental calves, with emphasis on weekly differences in the pre-weaning period. Ten Italian Simmental calves were used for the experiment and were offered 6 L of bulk whole milk/d from an open-bucket starting at day 2 from birth and through 5 weeks. Blood samples were collected at birth and weekly to assess biochemical indicators related to energy metabolism and liver function, minerals, markers of inflammation, and oxidative stress. Body weight (BW), heart girth (HG), and solid feed intake were positively affected by aging. Calves increased solid feed intake consumption after 2 week and reached a BW gain of 28.16 kg at 5 weeks. Most of blood biomarkers were affected by age, mostly concerned the period after birth and day 1, whereas no changes were observed for haptoglobin, urea, β-hydroxybutyrate, Na, and K. The amount of milk fed to calves throughout this study contributes to the maintenance of glucose concentration over time, coupled also with a considerable amount of starter intake. Glucose levels associated to the high ADG (0.89 ± 0.09 kg/d, mean ± SEM) suggest that calves experienced a positive energy balance throughout the entire pre-weaning period. Similar levels of haptoglobin and ceruloplasmin, together with a gradual increase of albumin, reflect good liver functionality and a stable condition regarding the inflammatory status. These results suggest that blood biomarkers of Simmental calves in the pre-weaning phase vary with growing stages.

中文翻译：

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断奶的西门塔尔牛犊断奶后饲喂全脂牛奶和随意喂食犊牛的年龄相关的代谢变化。

本研究旨在调查涵盖西门塔尔牛犊代谢状况的血液生物标志物，重点是断奶前每周的差异。实验中使用了十只意大利西门塔尔牛犊，从出生第二天开始至第5周，每天从开桶中抽取6升散装全脂牛奶。在出生时和每周收集血样，以评估与能量代谢和肝功能，矿物质，炎症标志物和氧化应激有关的生化指标。体重（BW），心围（HG）和固体饲料摄入量受到衰老的积极影响。犊牛在2周后增加了固体饲料的摄入量，在5周时体重增加了28.16 kg。大部分血液生物标志物均受年龄影响，主要涉及出生后的时期和第1天 而未观察到触珠蛋白，尿素，β-羟基丁酸酯，Na和K的变化。在整个研究过程中，喂给犊牛的牛奶量有助于维持一段时间内的葡萄糖浓度，同时还摄入了大量的发酵剂。高ADG（0.89±0.09 kg / d，平均值±SEM）相关的葡萄糖水平表明，犊牛在整个断奶前期都经历了正能量平衡。触珠蛋白和铜蓝蛋白水平相近，白蛋白逐渐增加，反映出良好的肝功能和炎症状态的稳定状况。这些结果表明，断奶前期西门塔尔牛的血液生物标志物随生长期而变化。在整个研究过程中，喂入犊牛的牛奶量有助于维持葡萄糖随时间的浓度，同时还需要大量的发酵剂。高ADG（0.89±0.09 kg / d，平均值±SEM）相关的葡萄糖水平表明，犊牛在整个断奶前期都经历了正能量平衡。触珠蛋白和铜蓝蛋白水平相近，白蛋白逐渐增加，反映出良好的肝功能和炎症状态的稳定状况。这些结果表明，断奶前期西门塔尔牛的血液生物标志物随着生长期而变化。在整个研究过程中，喂给犊牛的牛奶量有助于长期维持葡萄糖浓度，同时还需要摄入大量的发酵剂。高ADG（0.89±0.09 kg / d，平均值±SEM）相关的葡萄糖水平表明，犊牛在整个断奶前期都经历了正能量平衡。触珠蛋白和铜蓝蛋白水平相近，白蛋白逐渐增加，反映出良好的肝功能和炎症状态的稳定状况。这些结果表明，断奶前期西门塔尔牛的血液生物标志物随生长期而变化。平均值±标准差（SEM）表示犊牛在整个断奶前期均经历了正能量平衡。触珠蛋白和铜蓝蛋白水平相近，白蛋白逐渐增加，反映出良好的肝功能和炎症状态的稳定状况。这些结果表明，断奶前期西门塔尔牛的血液生物标志物随生长期而变化。平均值±标准差（SEM）表示犊牛在整个断奶前期均经历了正能量平衡。触珠蛋白和铜蓝蛋白水平相近，白蛋白逐渐增加，反映出良好的肝功能和炎症状态的稳定状况。这些结果表明，断奶前期西门塔尔牛的血液生物标志物随着生长期而变化。