为了研究牛乳中体细胞数对产奶量和乳汁成分的影响,采集西安草滩奶牛三场2004年处于泌乳盛期（2~4胎）的荷斯坦牛的奶样,测定体细胞数、乳脂率、乳蛋白率、日产奶量、胎次、泌乳阶段,共测341个样本。运用直线相关与回归方法,确定奶牛乳汁中体细胞数与产奶量、乳脂率及乳蛋白率的相关程度。结果表明：体细胞数与产奶量有极显著的负相关关系（r=-0.514,P〉0.01）,与乳脂率无显著相关关系（r=-0.045,P〉0.05）,与乳蛋白率无显著相关关系（r=0.035,P〉0.05）。说明体细胞数越高,奶量损失越大,当体细胞数超过110万/mL时,奶量损失达24.6%。因此,要充分利用奶牛牛群改良项目（dairy herd i m-provement,DHI）报表,加强对体细胞数的监控,及时预防和发现隐性乳房炎和临床乳房炎,减小经济损失,提高牛群的产奶性能。
Microflora in the intestinal tract and on the intestinal wall of both cultured and wild Apostichopus japonicus was studied in this paper. The screening for probiotics was performed based on enzyme producing and hemolytic analysis. The results showed that the number of bacteria in the intestinal wall and tract of wild Apostichopus japonicus was（3.30 ± 0.41） ×107cfu/g and（6.39 ± 0.32） ×10~7cfu/g, respectively. The number of bacteria in the intestinal wall and tract of cultured group was（2.83 ± 0.31） ×10~7cfu/g and（5.67 ± 0.53） ×10~7cfu/g, respectively. The dominant species in the intestinal tract of wild group was Vibrio and the Pseudomonas and Shewanella were the secondary dominant species. The dominant species in the cultured group was Vibrio and Pseudomonas. In 224 strains of bacteria, a total of160 strains of bacteria produced enzyme with a ratio of 71.43%. Among these bacteria, 114 strains could produce protease, 114 strains could produce amylase, and108 strains could produce lipase. The percentages were 50.89%, 50.89%, and48.21%, respectively. A total of 23 strains of bacteria could produce hemolytic toxin in 99 strains of bacteria, which accounts for 23.23% of the total bacterial population.Through the comprehensive analysis of test data, we selected 6 strains of bacteria as intestinal potential probiotic strains of Apostichopus japonicus, which were HS1（Pseudomonas）, HS5（Bacillus）, HS7（Shewanella）, HS8（Vibrio）, HS10（Vibrio）, and HS11（Vibrio） respectively.
