Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota 55108, USA.
J Dairy Sci. 2011 Sep;94(9):4457-67. doi: 10.3168/jds.2010-4047.
The objective of this multi-state, multi-herd clinical trial was to report on the efficacy of using an on-farm culture system to guide strategic treatment decisions in cows with clinical mastitis. The study was conducted in 8 commercial dairy farms ranging in size from 144 to 1,795 cows from Minnesota, Wisconsin, and Ontario, Canada. A total of 422 cows affected with mild or moderate clinical mastitis in 449 quarters were randomly assigned to either (1) a positive-control treatment program or (2) an on-farm culture-based treatment program. Quarter cases assigned to the positive-control group received immediate on-label intramammary treatment with cephapirin sodium. Quarters assigned to the culture-based treatment program were not treated until the results of on-farm culture were determined after 18 to 24h of incubation. Quarters in the culture-based treatment program that had gram-positive growth or a mixed infection were treated according to label instruction using intramammary cephapirin sodium. Quarters assigned to the culture-based treatment program that had gram-negative or no-growth did not receive intramammary therapy. It was already reported in a companion paper that the selective treatment of clinical mastitis based on on-farm culture results decreases antibiotic use by half and tends to decrease milk withholding time without affecting short-term clinical and bacteriological outcomes. The present article reports on long-term outcomes of the aforementioned study. No statistically significant differences existed between cases assigned to the positive-control program and cases assigned to the culture-based treatment program in risk and days for recurrence of clinical mastitis in the same quarter (35% and 78 d vs. 43% and 82 d), linear somatic cell count (4.2 vs. 4.4), daily milk production (30.0 vs. 30.7 kg), and risk and days for culling or death events (28% and 160 d vs. 32% and 137 d) for the rest of the lactation after enrollment of the clinical mastitis case. In summary, the selective treatment of clinical mastitis based on on-farm culture resulted in no differences in long-term outcomes, such as recurrence of clinical mastitis in the same quarter, somatic cell count, milk production, and cow survival for the rest of the lactation after clinical mastitis.
本多状态、多畜群临床试验的目的是报告在奶牛临床乳腺炎中使用农场培养系统来指导策略性治疗决策的疗效。该研究在明尼苏达州、威斯康星州和加拿大安大略省的 8 个商业奶牛场进行，这些奶牛场的规模从 144 头到 1795 头不等。共有 422 头患有轻度或中度临床乳腺炎的奶牛的 449 个乳区被随机分配到以下两组之一：（1）阳性对照治疗方案，或（2）基于农场培养的治疗方案。被分配到阳性对照组的乳区立即根据标签规定接受头孢匹林钠的乳房内治疗。分配到基于培养的治疗方案的乳区在孵育 18 至 24 小时后确定农场培养结果之前不进行治疗。在基于培养的治疗方案中，具有革兰氏阳性生长或混合感染的乳区根据标签说明使用头孢匹林钠进行乳房内治疗。分配到基于培养的治疗方案且具有革兰氏阴性或无生长的乳区不接受乳房内治疗。在一篇相关论文中已经报道过，基于农场培养结果的临床乳腺炎的选择性治疗可将抗生素的使用量减少一半，并倾向于缩短牛奶停供时间，而不会影响短期临床和细菌学结果。本文报告了上述研究的长期结果。在同一乳区临床乳腺炎复发的风险和天数（35%和 78 天与 43%和 82 天）、线性体细胞计数（4.2 与 4.4）、日产量（30.0 与 30.7 千克）以及淘汰或死亡事件的风险和天数（28%和 160 天与 32%和 137 天）方面，分配到阳性对照方案的病例与分配到基于培养的治疗方案的病例之间没有统计学上的显著差异，这些病例在临床乳腺炎病例入组后的整个泌乳期内。总之，基于农场培养的临床乳腺炎的选择性治疗在长期结果方面没有差异，例如同一乳区临床乳腺炎复发、体细胞计数、牛奶产量和临床乳腺炎后整个泌乳期的奶牛存活率。
