Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota 55108, USA.
J Dairy Sci. 2011 Sep;94(9):4441-56. doi: 10.3168/jds.2010-4046.
The objective of this multi-state, multi-herd clinical trial was to evaluate 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 cultured on-farm and treated with cephapirin sodium after 18 to 24h of incubation if they had gram-positive growth or a mixed infection. Quarters with gram-negative or no growth did not receive intramammary therapy. The proportion of quarter cases assigned to positive-control and culture-based treatments that received intramammary antibiotic therapy because of study assignment was 100 and 44%, respectively; the proportion of cases that received secondary antibiotic therapy was 36 and 19%, respectively; and the proportion of cases that received intramammary antibiotic therapy because of study assignment or secondary therapy was 100 and 51%, respectively. A tendency existed for a decrease in the number of days in which milk was discarded from cows assigned to the culture-based treatment program versus cows assigned to the positive-control group (5.9 vs. 5.2 d). No statistically significant differences existed between cases assigned to the positive-control and cases assigned to the culture-based treatment program in days to clinical cure (2.7 vs. 3.2 d), bacteriological cure risk within 21 d of enrollment (71 vs. 60%), new intramammary infection risk within 21 d of enrollment (50 vs. 50%), and treatment failure risk (presence of infection, secondary treatment, clinical mastitis recurrence, or removal from herd within 21 d after enrollment; 81 vs. 78%). In summary, the use of an on-farm culture system to guide the strategic treatment of clinical mastitis reduced intramammary antibiotic use by half and tended to decrease milk withholding time by 1 d, without significant differences in days to clinical cure, bacteriological cure risk, new intramammary infection risk, and treatment failure risk within 21 d after the clinical mastitis event.
本多状态、多畜群临床试验的目的是评估在患有临床乳腺炎的奶牛中使用农场培养系统来指导策略性治疗决策的效果。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，来自 449 个乳区，被随机分配到（1）阳性对照治疗方案或（2）农场培养物为基础的治疗方案。分配到阳性对照组的quarters 病例立即接受头孢匹林钠的标签内治疗。如果在孵育 18 至 24 小时后培养物呈革兰氏阳性生长或混合感染，则分配到基于培养物的治疗方案的quarters 会在农场进行培养，并在培养物呈革兰氏阴性或无生长时，不接受乳房内抗生素治疗。由于研究分配，分配到阳性对照和基于培养物的治疗组的 quarters 病例中，接受乳房内抗生素治疗的比例分别为 100%和 44%；接受二线抗生素治疗的比例分别为 36%和 19%；由于研究分配或二线治疗而接受乳房内抗生素治疗的比例分别为 100%和 51%。与分配到阳性对照组的奶牛相比，分配到基于培养物的治疗组的奶牛的牛奶废弃天数有减少的趋势（5.9 天比 5.2 天）。在临床治愈天数（2.7 天比 3.2 天）、入学后 21 天内的细菌学治愈率风险（71%比 60%）、入学后 21 天内新的乳房内感染风险（50%比 50%）以及治疗失败风险（感染、二线治疗、临床乳腺炎复发或入学后 21 天内从牛群中移除；81%比 78%）方面，分配到阳性对照和基于培养物的治疗组的病例之间没有统计学上的显著差异。总之，使用农场培养系统指导临床乳腺炎的策略性治疗将乳房内抗生素的使用减少了一半，并倾向于将牛奶停供时间减少 1 天，但在临床治愈天数、细菌学治愈率风险、新的乳房内感染风险以及临床乳腺炎发病后 21 天内的治疗失败风险方面没有显著差异。
