Bramley A J, Schultze W D
Agricultural and Food Research Council, Institute for Animal Health, Compton Laboratory, Newbury, England.
J Dairy Sci. 1991 Sep;74(9):2982-8. doi: 10.3168/jds.S0022-0302(91)78484-1.
Forty quarters of 10 cows were milked for a 9-d period with one of four treatments: 1) no liner pulsation, 2) conventional milking, 3) no pulsation for 4 d followed by conventional milking for 5 d, and 4) conventional milking for 4 d followed by milking without pulsation for 5 d. All teat orifices were inoculated with approximately .5 million cfu of Streptococcus agalactiae and Streptococcus dysgalactiae on d 1 and 5. Recoveries of Strep. agalactiae from the teat end were increased for teats milked without pulsation. Recoveries of Strep. dysgalactiae were lower than those of Strep. agalactiae and not increased by milking without pulsation. In a second experiment, teats of 20 cows were milked for a 15-d period with or without liner pulsation. For 10 successive milkings, all teats were inoculated with 1.0 micrograms of Escherichia coli endotoxin either immediately or 2.5 h after each milking. The frequency of endotoxin penetration, measured by the Wisconsin Mastitis Test, in pulsated quarters and in nonpulsated quarters was similar. For quarters milked without pulsation but not for pulsated quarters, inoculation of endotoxin immediately after milking led to greater incidence of teat duct penetration than for inoculation 2.5 h after milking.
选用10头奶牛，每头奶牛的4个乳区进行为期9天的挤奶试验，共设4种处理：1）无奶衬脉动；2）传统挤奶；3）前4天无脉动，后5天传统挤奶；4）前4天传统挤奶，后5天无脉动挤奶。在第1天和第5天，所有乳头开口处接种约50万个cfu的无乳链球菌和停乳链球菌。无脉动挤奶的乳头，其乳头末端无乳链球菌的回收率增加。停乳链球菌的回收率低于无乳链球菌，且无脉动挤奶未使其回收率增加。在第二项试验中，选用20头奶牛，其乳头进行为期15天的有或无奶衬脉动挤奶。在连续10次挤奶过程中，每次挤奶后立即或2.5小时后，所有乳头接种1.0微克大肠杆菌内毒素。通过威斯康星乳房炎检测法测定，有脉动乳区和无脉动乳区内毒素渗透频率相似。对于无脉动挤奶的乳区，而非有脉动挤奶的乳区，挤奶后立即接种内毒素比挤奶后2.5小时接种导致乳头管渗透的发生率更高。
