Langlois B E, Cox J S, Hemken R H, Nicolai J
J Dairy Sci. 1981 Sep;64(9):1837-42. doi: 10.3168/jds.S0022-0302(81)82773-7.
In 23 first-calf heifers we ascertained effects that milking vacuums of 34, 42.5, and 51 kPa had on udder health by percentage of quarter-samples positive for Staphylococcus aureus, total counts of bacteria on blood agar, teat end scores, California Mastitis Test, and direct microscopic somatic cell count. Measures were higher for 51 kPa than for 34 or 42.5 kPA. Samples from cows milked at 42.5 kPa had a lower percentage of samples positive for Staphylococcus aureus, lower total count, lower California Mastitis Test, and lower direct microscopic somatic cell count than samples from cows milked with 34 kPa. Test end scores increased with increase in milking vacuum. Approximately 49% of the samples from cows milked with 51 KPa were positive for Staphylococcus aureus compared with 19.9 and 16.7% for 34 and 42.5 kPa. Milking vacuum of 51 kPa resulted in the highest percentage of cows with three (44.5%) and four (24.1%) quarters positive for Staphylococcus aureus. A milking vacuum of 51 kPa could increase mastitis in a herd having Staphylococcus aureus as the prevalent microorganism causing mastitis.
在23头初产小母牛中，我们通过金黄色葡萄球菌检测呈阳性的乳腺区样本百分比、血琼脂上的细菌总数、乳头末端评分、加利福尼亚乳房炎检测以及直接显微镜体细胞计数，确定了34、42.5和51千帕的挤奶真空度对乳房健康的影响。51千帕时的各项指标高于34或42.5千帕时的指标。与以34千帕挤奶的奶牛样本相比，以42.5千帕挤奶的奶牛样本中，金黄色葡萄球菌检测呈阳性的样本百分比更低、细菌总数更低、加利福尼亚乳房炎检测结果更低，且直接显微镜体细胞计数更低。乳头末端评分随挤奶真空度的增加而升高。以51千帕挤奶的奶牛样本中，约49%金黄色葡萄球菌检测呈阳性，而以34千帕和42.5千帕挤奶的这一比例分别为19.9%和16.7%。51千帕的挤奶真空度导致三（44.5%）个和四（24.1%）个乳腺区金黄色葡萄球菌检测呈阳性的奶牛比例最高。对于以金黄色葡萄球菌作为引起乳房炎的主要微生物的牛群，51千帕的挤奶真空度可能会增加乳房炎的发病率。
