Ntallaris T, Humblot P, Båge R, Sjunnesson Y, Dupont J, Berglund B
Department of Clinical Sciences, Swedish University of Agricultural Sciences, SLU, Uppsala, Sweden; Centre for Reproductive Biology in Uppsala, CRU, Uppsala, Sweden.
INRA PRC, Nouzilly, France.
Theriogenology. 2017 Mar 1;90:276-283. doi: 10.1016/j.theriogenology.2016.12.012. Epub 2016 Dec 18.
This study examined the effect of two feeding levels during the antepartum and postpartum period on reproductive performance and blood metabolites (glucose, non-esterified fatty acids (NEFA), insulin) in primiparous Holstein and Swedish Red (SRB) cows, in order to identify possible differences in the way these breeds respond to negative energy balance after calving. A total of 44 cows (22 Holstein, 22 SRB) kept in a loose housing system were included in the study. The control group (HE, n = 23) was fed a diet for high-producing cows (target 35 kg/d energycorrected milk, ECM). A lower feeding intensity (LE, n = 21) was achieved by giving -50% concentrate to target 25 kg/d ECM. Diets were implemented 30 days before expected calving and the cows were monitored for 120 days postpartum. Milk yield and composition, dry matter intake (DMI), live body weight and body condition score (BCS) were assessed to calculate the weekly energy balance (residual feed intake). Blood sampling started before diet implementation and was repeated every 2 weeks until Day 60 postpartum and then once monthly until Day 120. Plasma was kept at -20 °C until analysis for glucose, insulin and NEFA concentrations. Mixed linear models were used to analyse data (SAS 9.3; PROC MIXED). Holstein cows had lower mean energy balance than SRB cows (-4.7 ± 1.4 and -0.9 ± 1.4 MJ, respectively; p = 0.05). SRB cows had higher (p<0.001) BCS (3.3 ± 0.1) than Holstein cows (2.7 ± 0.1) and also higher plasma glucose concentrations from Day -30 to Day 120 relative to parturition (4.1 ± 0.1 and 4.2 ± 0.1 log ; mg/100 ml, respectively; p < 0.05). Overall, breed or diet had no effect on NEFA blood plasma concentrations. However, plasma NEFA concentration levels tended to be higher (p = 0.09) in SRB cows than in Holsteins at Day -14 before calving, indicating higher mobilisation of lipid from adipose tissue already before calving. In contrast, Holstein cows had higher NEFA at Day 14 postpartum than SRB cows (p < 0.05). There were no significant effects of diet or breed on reproductive performance (% pregnant at first AI, days open). However, commencement of luteal activity within 21d postpartum was affected (p < 0.05) by the interaction of breed and diet. These results suggest that Holstein cows prioritise milk production to a larger extent than SRB cows, resulting in a less balanced metabolic profile.
本研究考察了初产荷斯坦奶牛和瑞典红牛在产前和产后两个饲养水平对繁殖性能和血液代谢物（葡萄糖、非酯化脂肪酸（NEFA）、胰岛素）的影响，以确定这些品种在产犊后对负能量平衡反应方式上可能存在的差异。本研究共纳入了44头饲养在散栏饲养系统中的奶牛（22头荷斯坦奶牛，22头瑞典红牛）。对照组（HE，n = 23）饲喂高产奶牛日粮（目标为35 kg/d能量校正乳，ECM）。通过减少50%的精料供给，使饲喂强度降低（LE，n = 21），目标为25 kg/d ECM。在预计产犊前30天实施日粮，并对奶牛产后120天进行监测。评估产奶量和组成、干物质摄入量（DMI）、活体重和体况评分（BCS），以计算每周能量平衡（剩余采食量）。在日粮实施前开始采血，每2周重复一次，直至产后60天，然后每月一次，直至产后120天。血浆保存在-20°C直至分析葡萄糖、胰岛素和NEFA浓度。使用混合线性模型分析数据（SAS 9.3；PROC MIXED）。荷斯坦奶牛的平均能量平衡低于瑞典红牛（分别为-4.7±1.4和-0.9±1.4 MJ；p = 0.05）。瑞典红牛的BCS（3.3±0.1）高于荷斯坦奶牛（2.7±0.1）（p<0.001），并且在相对于分娩的第-30天至第120天，血浆葡萄糖浓度也更高（分别为4.1±0.1和4.2±0.1 log；mg/100 ml，p<0.05）。总体而言，品种或日粮对血浆NEFA浓度没有影响。然而，在产犊前14天，瑞典红牛的血浆NEFA浓度水平趋于高于荷斯坦奶牛（p = 0.09），表明在产犊前脂肪组织中脂质的动员已经更高。相比之下，产后14天荷斯坦奶牛的NEFA高于瑞典红牛（p<0.05）。日粮或品种对繁殖性能（首次人工授精的妊娠率、空怀天数）没有显著影响。然而，产后21天内黄体活动的开始受到品种和日粮相互作用的影响（p<0.05）。这些结果表明，荷斯坦奶牛比瑞典红牛在更大程度上优先考虑产奶量，导致代谢状况较不均衡。
