Peripartal metabolism and production of holstein cows fed diets supplemented with fat during the dry period.
Peripartal metabolism and production of holstein cows fed diets supplemented with fat during the dry period.
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DOI：
10.3168/jds.s0022-0302(04)73566-3
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发表时间：
2004-12
影响因子：
3.5
通讯作者：
G. N. Douglas;T. R. Overton;H. G. Bateman;J. Drackley
中科院分区：
文献类型：
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作者：
G. N. Douglas;T. R. Overton;H. G. Bateman;J. Drackley
我们实验室之前的研究表明，与饲喂等热量高谷物日粮或低能量控制日粮的奶牛相比，为了提高体况评分 (BCS) 而在整个干奶期饲喂补充脂肪的奶牛在产后第 1 天几乎没有肝脏脂质积累。然而，由于饲喂添加脂肪的日粮的奶牛干物质摄入量较低和 BCS 损失，结果令人困惑。在此，给奶牛饲喂非纤维碳水化合物 (NFC) 含量较高的对照饮食 (C) 或补充等热量脂肪的低 NFC (F) 饮食，以重新评估整个干奶期补充脂肪对肝脏围产期脂质积累的影响。还喂食能量密度更高、添加脂肪 (CF) 的高 NFC 饮食，以测试在碳水化合物成分相似但能量密度更高的饮食中补充脂肪的功效。在整个实验过程中，各处理组的泌乳干物质和净能量摄入量相似，但分娩前最后 21 天的饮食 x 天相互作用表明，饲喂 CF 的奶牛摄入量下降得更慢。奶牛在产前饮食中获得了相似数量的 BCS 和体重，但饲喂 C 的奶牛在分娩前后往往会损失更多的 BCS 和体重。不同处理之间的产奶量和牛奶成分没有差异。各治疗组的产前血浆中葡萄糖、胰岛素、总蛋白、非酯化脂肪酸和μ-羟基丁酸浓度相似。补充脂肪增加了产前血浆中尿素和胆固醇的浓度。各治疗组的产后血浆中代谢物和胰岛素浓度相似。分娩时肝脏中总脂质和甘油三酯的浓度升高，而肝糖原浓度降低，但各处理之间的浓度没有差异。产前补充脂肪不会影响围产期肝组织中的脂质积累，也不利于产后产奶。
Previous research from our laboratory demonstrated that cows fed supplemental fat throughout the dry period in an attempt to increase body condition score (BCS) had little hepatic lipid accumulation at d 1 postpartum compared with cows fed an isocaloric high-grain diet or a lower energy control diet. However, results were confounded by lower dry matter intake and loss of BCS by cows fed the fat-supplemented diet. Here, cows were fed a control diet (C) moderately high in nonfiber carbohydrates (NFC) or an isocaloric fat-supplemented, low NFC (F) diet to reassess the effects of supplemental fat throughout the dry period on peripartal lipid accumulation in liver. A more energy-dense, high-NFC diet supplemented with fat (CF) was also fed to test the efficacy of supplemental fat in a diet with similar carbohydrate composition but higher energy density. Intakes of dry matter and net energy for lactation were similar among treatments throughout the experiment, although diet x day interactions during the last 21 d before parturition indicated that cows fed CF decreased intakes more slowly. Cows gained similar amounts of BCS and body weight among diets prepartum, but cows fed C tended to lose more BCS and body weight around parturition. Milk production and milk components did not differ among treatments. Prepartum concentrations of glucose, insulin, total protein, nonesterified fatty acids, and mu-hydroxybutyrate in plasma were similar among treatments. Supplemental fat increased prepartum concentrations of urea and cholesterol in plasma. Postpartum concentrations of metabolites and insulin in plasma were similar among treatments. Concentrations of total lipid and triglyceride in liver increased at parturition, whereas hepatic glycogen concentration decreased, but concentrations were not different among treatments. Supplemental fat fed prepartum did not affect peripartal lipid accumulation in liver tissue and did not benefit postpartum milk production.