Weiss W P, Wyatt D J, McKelvey T R
Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691, USA.
J Dairy Sci. 2008 Feb;91(2):646-52. doi: 10.3168/jds.2007-0693.
This experiment was conducted to determine the effect of a direct-fed microbial agent, Propionibacterium strain P169 (P169), on rumen fermentation, milk production, and health of periparturient and early-lactation dairy cows. Starting 2 wk before anticipated calving, cows were divided into 2 groups and fed a control diet or the control diet plus 6 x 10(11) cfu/d of P169. Cows were changed to a lactation diet at calving, and treatments continued until 119 d in milk. Rumen fluid samples were taken about 1 wk before calving, and at 1 and 14 wk after calving. Cows fed P169 had lower concentrations of acetate (mol/100 mol of total volatile fatty acids) at all time points, greater concentrations of propionate on the first and last sampling points, and greater concentrations of butyrate on the first 2 time points. Concentrations of glucose in plasma and milk and plasma concentrations of beta-hydroxybutyrate were not affected by treatment. Cows fed P169 had greater concentrations of plasma nonesterified fatty acids on d 7 of lactation. The high nonesterified fatty acids at that time point was probably related to the high production of milk during that period by cows fed the additive. Cows fed P169 during the first 17 wk of lactation produced similar amounts of milk (44.9 vs. 45.3 kg/d, treatment vs. control) with similar composition as cows fed the control diet. Calculated net energy use for milk production, maintenance, and body weight change was similar between treatments, but cows fed the P169 consumed less dry matter (22.5 vs. 23.5 kg/d), which resulted in a 4.4% increase in energetic efficiency.
本试验旨在确定直接投喂微生物制剂丙酸杆菌菌株P169（P169）对围产期和泌乳早期奶牛瘤胃发酵、产奶性能及健康状况的影响。在预计产犊前2周开始，将奶牛分为两组，分别饲喂对照日粮或对照日粮加6×10¹¹ cfu/d的P169。产犊时奶牛更换为泌乳日粮，处理持续至产奶119天。在产犊前约1周、产犊后1周和14周采集瘤胃液样本。饲喂P169的奶牛在所有时间点的乙酸盐浓度（每100摩尔总挥发性脂肪酸中的摩尔数）均较低，在第一个和最后一个采样点的丙酸盐浓度较高，在前两个时间点的丁酸盐浓度较高。血浆和乳中葡萄糖浓度以及血浆β-羟基丁酸盐浓度不受处理影响。饲喂P169的奶牛在泌乳第7天的血浆非酯化脂肪酸浓度较高。该时间点较高的非酯化脂肪酸可能与饲喂添加剂的奶牛在此期间的高产奶量有关。在泌乳的前17周饲喂P169的奶牛产奶量（44.9对45.3 kg/d，处理组对对照组）和奶成分与饲喂对照日粮的奶牛相似。计算得出的产奶、维持和体重变化的净能量利用在处理组间相似，但饲喂P169的奶牛消耗的干物质较少（22.5对23.5 kg/d），能量效率提高了4.4%。
