State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
J Anim Sci Biotechnol. 2014 May 29;5(1):30. doi: 10.1186/2049-1891-5-30. eCollection 2014.
Energy intake prepartum is critically important to health, milk performance, and profitability of dairy cows. The objective of this study was to determine the effect of reduced energy density of close-up diets on dry matter intake (DMI), lactation performance and energy balance (EB) in multiparous Holstein cows which were housed in a free-stall barn and fed for ad libitum intake. Thirty-nine dry cows were blocked and assigned randomly to three groups fed a high energy density diet [HD, n = 13; 6.8 MJ of net energy for lactation (NEL)/kg; 14.0% crude protein (CP) ], or a middle energy density diet (MD, n = 13; 6.2 MJ NEL/kg; 14.0% CP), or a low energy density diet (LD, n = 13; 5.4 MJ NEL/kg; 14.0% CP) from d 21 before expected day of calving. After parturition, all cows were fed the same lactation diet to d 70 in milk (DIM). The DMI and NEL intake prepartum were decreased by the reduced energy density diets (P < 0.05). The LD group consumed 1.3 kg/d (DM) more diet compared with HD group in the last 24 h before calving. The milk yield and the postpartum DMI were increased by the reduced energy density diet prepartum (P < 0.05). The changes in BCS and BW prepartum and postpartum were not affected by prepartum diets. HD group had higher milk fat content and lower lactose content compared with LD group during the first 3 wk of lactation (P < 0.05). The energy consumption for HD, MD and LD groups were 149.8%, 126.2% and 101.1% of their calculated energy requirements prepartum (P < 0.05), and 72.7%, 73.1% and 75.2% during the first 4 wk postpartum, respectively. In conclusion, the low energy density prepartum diet was effective in controlling NEL intake prepartum, and was beneficial in increasing DMI and milk yield, and alleviating negative EB postpartum.
围产前期的能量摄入对奶牛的健康、产奶性能和盈利能力至关重要。本研究的目的是确定在自由卧床牛舍中饲养的经产荷斯坦奶牛，日粮能量密度降低对干物质采食量（DMI）、泌乳性能和能量平衡（EB）的影响，这些奶牛可自由采食。39 头干奶牛按组间随机分为 3 组，分别饲喂高能密度日粮（HD，n=13；泌乳净能（NEL）/kg 为 6.8MJ；粗蛋白（CP）14.0%）、中能密度日粮（MD，n=13；NEL/kg 为 6.2MJ；CP 14.0%）或低能密度日粮（LD，n=13；NEL/kg 为 5.4MJ；CP 14.0%），从预计分娩日前 21d 开始饲喂。分娩后，所有奶牛在泌乳第 70 天（DIM）前均饲喂相同的泌乳日粮。围产前期降低能量密度日粮会降低奶牛的 DMI 和 NEL 摄入量（P＜0.05）。与 HD 组相比，LD 组在分娩前最后 24h 多采食 1.3kg/d（DM）日粮。围产前期降低能量密度日粮可增加产后 DMI（P＜0.05）和产奶量。围产前期和产后奶牛的体况评分（BCS）和体重（BW）变化不受围产前期日粮的影响。与 LD 组相比，HD 组在泌乳前 3 周的牛奶脂肪含量较高，乳糖含量较低（P＜0.05）。HD、MD 和 LD 组在围产前期的能量消耗分别为其计算能量需求的 149.8%、126.2%和 101.1%（P＜0.05），产后前 4 周分别为 72.7%、73.1%和 75.2%。综上所述，围产前期低能量密度日粮可有效控制 NEL 摄入，增加 DMI 和产奶量，缓解产后负 EB。
