Hillerton J E, Semmens J E
Institute for Animal Health, Newbury, Berks, United Kingdom.
J Dairy Sci. 1999 Jan;82(1):93-8. doi: 10.3168/jds.S0022-0302(99)75213-6.
Mastitis was induced in dairy cows by infusion of 500 cfu of Streptococcus uberis into the mammary gland. Most infections developed to clinical disease, and the majority were predicted by changes in the electrical conductivity of the foremilk. The benefits of clinical prognosis and bacteriological cure were determined for cases that were treated when predicted to develop into clinical mastitis and compared with cases that were allowed to develop until milk clotted or until pyrexia before intramammary antibiotic treatment was used. Treatment prior to clinical mastitis included use of intramammary antibiotic or intramuscular oxytocin to allow stripping of residual milk to remove bacteria. All infections in which treatment was delayed resulted in clinical mastitis that was cured clinically and bacteriologically by sustained treatment using a broad-spectrum intramammary antibiotic preparation once daily but requiring a mean treatment time of 10 d. It was possible to prevent clinical mastitis from developing and to eliminate all infections in cows that were treated early when the developing disease was predicted by changes in the electrical conductivity of quarter foremilk and was treated aggressively by administering an intramammary antibiotic at each milking for 3 d. Treatment of 20 IU of oxytocin at six successive milkings of cows that were predicted to develop disease eliminated 25% of the infections, but 75% of the cows developed clinical mastitis. Those cases were resolved by sustained daily treatment using the same intramammary antibiotic. Elimination (100% clinical and bacteriological cure) of all infections caused by Strep. uberis was possible with early and aggressive or sustained use of the intramammary antibiotic. The early intervention using an intramammary antibiotic, when infection was first indicated by changes in the electrical conductivity of milk, was the most efficient method to achieve cure and led to quicker recovery of milk quality to a saleable standard.
通过向奶牛乳腺内注入500 cfu乳房链球菌来诱发乳腺炎。大多数感染发展为临床疾病，且大多数可通过前乳电导率的变化预测。对于预计会发展为临床乳腺炎时进行治疗的病例，确定其临床预后和细菌学治愈的益处，并与那些在乳房内使用抗生素治疗前，任其发展至乳汁凝结或发热的病例进行比较。临床乳腺炎发生前的治疗包括使用乳房内抗生素或肌内注射催产素，以便挤出残留乳汁以清除细菌。所有延迟治疗的感染均导致临床乳腺炎，通过每天一次持续使用广谱乳房内抗生素制剂进行治疗，临床和细菌学上均得以治愈，但平均治疗时间需要10天。当通过四分之一前乳电导率的变化预测到疾病发展，并在每次挤奶时积极给予乳房内抗生素治疗3天，有可能预防临床乳腺炎的发生，并消除早期治疗奶牛的所有感染。对预计会发病的奶牛连续六次挤奶时每次注射20 IU催产素进行治疗，消除了25%的感染，但75%的奶牛发展为临床乳腺炎。这些病例通过持续每日使用相同的乳房内抗生素得以解决。通过早期积极或持续使用乳房内抗生素，有可能消除由乳房链球菌引起的所有感染（100%临床和细菌学治愈）。当乳汁电导率变化首次表明感染时，早期使用乳房内抗生素进行干预是实现治愈的最有效方法，并能使乳汁质量更快恢复到可销售标准。
