Concentrate feeding strategy in lactating dairy cows: Metabolic and endocrine changes with emphasis on leptin
Concentrate feeding strategy in lactating dairy cows: Metabolic and endocrine changes with emphasis on leptin
复制标题
DOI：
10.3168/jds.s0022-0302(03)73755-2
复制
发表时间：
2003-05-01
影响因子：
3.5
通讯作者：
Blum, JW
中科院分区：
文献类型：
--
作者：
Reist, M;Erdin, D;Blum, JW
本研究旨在评估经产荷斯坦奶牛(n=90，平均产奶量为9434 kg/305d)在产后20周内对能量摄入的代谢和内分泌适应性，并评估瘦素与代谢、内分泌和动物技术性状的关系。从产后第1周到第10周，以总干物质摄入量的30%(C30)或50%(C50)自动饲喂精料24小时，此后以线性减量饲喂。按自由采食量饲喂粗饲料，24小时后测定日增重、产奶量和体重(BW)，每天2次。牛奶成分，4次/周；牛奶丙酮，每周。分别于产前2周、产后1~16周和产后20周采血测定代谢物、激素和电解质浓度及酶活性。分别在产后第1、4、8、12、16、20周测量产后体况、BCS和背脂厚度。能量平衡(EB)显著低于C50，但产奶量仅略低于C50。C30较C50代谢应激更明显，表现为低血糖、胰岛素、胰岛素样生长因子-1。IGF-1、三碘甲腺原氨酸、乳蛋白和乳糖浓度升高，非酯化脂肪酸、β-羟丁酸、生长激素和乳丙酮浓度升高，BCS和背脂厚度加速下降。然而，C30成功地适应了环境，因此尽管EB为负值，但仍保持了高产奶量。在产后20周内，C30组瘦素水平低于C50组，且与BCS、EB、BW、胆固醇、白蛋白、胰岛素和IGF-1呈正相关，与DMI和三碘甲腺原氨酸呈负相关，春季产犊奶牛高于秋季产犊奶牛。瘦素是参与能量代谢调节的几个因素之一，对代谢的整体稳态和顺势控制可能很重要，因此对维持运动能力也很重要。
This study aimed to evaluate metabolic and endocrine adaptations to energy intake in multiparous Holstein cows (n = 90; mean 9434 kg energy-corrected milk yield/305 d) over the first 20 wk postpartum and to assess the association of leptin with metabolic, endocrine, and zootechnical traits. Concentrates were fed automatically for 24, h at 30% (C30) or 50% (C50) of total dry matter intake (DMI) from wk 1 to 10 postpartum and at linearly reduced amounts thereafter. Roughage was fed for ad libitum intakes The DMI was measured over 24 h; milk yield and body weight (BW), twice/d;. milk composition, 4 times/wk; and milk acetone, weekly. Blood samples for determination of metabolite, hormone, and electrolyte concentrations and enzyme activities were obtained at wk 2 prepartum, and, at wk 1 to 16 and at wk 20 postpartum from 0730 to 0900. Body condition, scores (BCS) and backfat thickness were measured postpartum and during wk 1, 4, 8, 12, 16, and 20. Energy balance (EB) was considerably lower, but milk yield only slightly lower, in C30 than C50. Metabolic stress was more marked in C30 than C50, expressed by lower, glucose, insulin, insulin-like growth factor-1. (IGF-1), triiodothyronine, milk protein, and lactose concentrations, higher nonesterified fatty acid, beta-hydroxybutyrate, growth hormone, and milk acetone concentrations, and an accelerated decrease in BCS and backfat thickness. Nevertheless C30 adapted successfully and thus maintained high milk yields despite negative EB. Leptin concentrations were lower in C30 than in C50 over the first 20 wk postpartum and were positively associated with BCS, EB, BW, cholesterol, albumin, insulin, and IGF-1; negatively associated with DMI and triiodothyronine; and were higher in cows calving in spring than in fall. Leptin is one among several factors involved in the regulation of energy metabolism and may be important for overall homeostatic and homeorhetic control of metabolism and thus for maintenance of performance.