Supplemental Material - Association between prepartum body condition score and prepartum and postpartum dry matter intake and energy balance in multiparous Holstein cows

The objectives of this retrospective observational study were to investigate the association between body condition score (BCS) at 21 d before calving with prepartum and postpartum dry matter intake (DMI), energy balance (EB), and milk yield. Data from 427 multigravid cows from 11 different experiments conducted at the University of Florida were used. Cows were classified according to their BCS at 21 d before calving as FAT (BCS ≥ 4.00; n = 83), MOD (BCS 3.25 to 3.75; n = 287), and THIN (BCS ≤ 3.00; n = 57). Daily DMI from −21 to −1 and from +1 to +28 DIM was individually recorded. Energy balance was calculated as the difference between net energy for lactation consumed and required. Dry matter intake in FAT cows was lesser than in MOD and THIN cows both prepartum (FAT = 9.97 ± 0.21, MOD = 11.15 ± 0.14, THIN = 11.92 ± 0.22 kg/d) and postpartum (FAT = 14.35 ± 0.49, MOD = 15.47 ± 0.38, THIN = 16.09 ± 0.47 kg/d). Dry matter intake was also lesser for MOD cows compared with THIN cows prepartum, but not postpartum. Energy balance in FAT cows was lesser than in MOD and THIN cows both prepartum (FAT = -4.16 ± 0.61, MOD = -1.20 ± 0.56, THIN = 0.88 ± 0.62 Mcal/d) and postpartum (FAT = -12.77 ± 0.50, MOD = -10.13 ± 0.29, THIN = -6.14 ± 0.51 Mcal/d). Energy balance was also lesser for MOD cows compared with THIN cows both prepartum and postpartum. There was a quadratic association between BCS at 21 d before calving and milk yield. Increasing BCS from 2.5 to 3.5 was associated with an increase in daily milk yield of 6.0 kg and 28 d cumulative milk of 147 kg. Increasing BCS from 3.5 to 4.5 was associated with a decrease in daily milk yield of 4.4 kg and 28 d cumulative milk of 116 kg. In summary, a moderated BCS at 21 d before calving was associated with intermediate DMI and EB pre- and postpartum but greater milk yield compared with thinner and fatter cows. Our findings indicate that a moderated BCS is ideal for ensuring a successful lactation.

本研究回顾性观察性研究旨在探讨分娩前21天奶牛体况评分（BCS）与分娩前后干物质摄入量（DMI）、能量平衡（EB）及产奶量之间的关联。本研究利用了佛罗里达大学进行的11个不同实验中的427头多胎次奶牛的数据。奶牛根据其分娩前21天的BCS分为肥胖组（BCS≥4.00；n=83）、中度肥胖组（BCS 3.25至3.75；n=287）和瘦弱组（BCS≤3.00；n=57）。从分娩前21天至分娩前1天和分娩后1天至分娩后28天，每日DMI均进行了单独记录。能量平衡通过消耗与需求之间的净能量差异进行计算。肥胖组奶牛的DMI在分娩前后均低于中度肥胖组和瘦弱组奶牛（分娩前：肥胖组=9.97±0.21，中度肥胖组=11.15±0.14，瘦弱组=11.92±0.22 kg/d；分娩后：肥胖组=14.35±0.49，中度肥胖组=15.47±0.38，瘦弱组=16.09±0.47 kg/d）。中度肥胖组奶牛在分娩前的DMI也低于瘦弱组奶牛，但在分娩后则不然。肥胖组奶牛在分娩前后能量平衡均低于中度肥胖组和瘦弱组奶牛（分娩前：肥胖组=-4.16±0.61，中度肥胖组=-1.20±0.56，瘦弱组=0.88±0.62 Mcal/d；分娩后：肥胖组=-12.77±0.50，中度肥胖组=-10.13±0.29，瘦弱组=-6.14±0.51 Mcal/d）。中度肥胖组奶牛在分娩前后能量平衡也低于瘦弱组奶牛。分娩前21天BCS与产奶量之间存在二次关联。BCS从2.5增至3.5时，日奶产量增加6.0 kg，28天累积奶量增加147 kg。BCS从3.5增至4.5时，日奶产量减少4.4 kg，28天累积奶量减少116 kg。总之，分娩前21天适度BCS与分娩前后中间的DMI和EB相关，但与较瘦和较胖的奶牛相比，产奶量更高。我们的研究结果指出，适度BCS对于确保成功的泌乳期至关重要。