Robinson P H, Garrett J E
Department of Animal Science, University of California, Davis 95616-8521, USA.
J Anim Sci. 1999 Apr;77(4):988-99. doi: 10.2527/1999.774988x.
Multiparous (n = 26) and primiparous (n = 18) Holstein cows were fed prepartum and postpartum total mixed diets that were, or were not, supplemented with a yeast culture (YC) for approximately 23 d prepartum and 56 d postpartum. Multiparous cows supplemented with YC selected a prepartum diet higher in CP than did unsupplemented cows, although prepartum performance of cows of both parities, as assessed by DMI and measures of body status, was not influenced by YC. The extent of the prepartum DMI depression was not influenced by YC supplementation in cows of either parity. An intake behavior study with six multiparous cows suggested that cows supplemented with YC exhibited repeated diurnal feed intake patterns until approximately 7 d prepartum, vs 10 d prepartum for unsupplemented cows. Cows of both parities supplemented with YC had numerically higher DMI and production of milk and milk components, although only DMI for multiparous cows and milk production for primiparous cows approached statistical significance. Intake behavior results suggested that cows supplemented with YC achieved repeated diurnal feed intake patterns by approximately 14 d postpartum, vs 20 d postpartum for unsupplemented cows. Concentrations of ruminal metabolites and pH did not differ between treatments, although ruminal fluid collection occurred while diurnal feed intake patterns were repeated (regular). Overall, our results can be interpreted to support a trend toward a modest postpartum improvement in performance of primiparous and multiparous cows supplemented with this YC for 23 d prepartum and 56 d postpartum. However, primiparous cows seemed to achieve this modest overall improvement primarily through enhanced postpartum DMI, whereas in multiparous cows it was due almost equally to enhanced postpartum DMI and higher energy density of the diet.
对经产（n = 26）和初产（n = 18）的荷斯坦奶牛在产前和产后分别饲喂全混合日粮，产前和产后日粮有的添加了酵母培养物（YC），有的未添加，产前约23天，产后56天。添加YC的经产奶牛选择的产前日粮粗蛋白含量高于未添加的奶牛，不过，通过干物质采食量（DMI）和体况测量评估的两个胎次奶牛的产前性能均不受YC影响。两个胎次奶牛的产前DMI下降程度均不受YC添加的影响。一项对6头经产奶牛的采食行为研究表明，添加YC的奶牛在产前约7天表现出重复的昼夜采食模式，而未添加的奶牛则在产前10天出现这种模式。两个胎次添加YC的奶牛在数值上DMI以及牛奶和牛奶成分产量更高，不过只有经产奶牛的DMI和初产奶牛的产奶量接近统计学显著水平。采食行为结果表明，添加YC的奶牛在产后约14天实现了重复的昼夜采食模式，而未添加的奶牛则在产后20天实现。瘤胃代谢物浓度和pH在各处理间无差异，不过瘤胃液采集是在昼夜采食模式重复（规律）时进行的。总体而言，我们的结果可以解释为支持一种趋势，即产前23天和产后56天添加这种YC的初产和经产奶牛产后性能有适度改善。然而，初产奶牛似乎主要通过提高产后DMI实现这种适度的整体改善，而经产奶牛几乎同样归因于产后DMI的提高和日粮能量密度的增加。
