Randomized noninferiority clinical trial evaluating 3 commercial dry cow mastitis preparations: I. Quarter-level outcomes
Randomized noninferiority clinical trial evaluating 3 commercial dry cow mastitis preparations: I. Quarter-level outcomes
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DOI：
10.3168/jds.2012-6461
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发表时间：
2013-07-01
影响因子：
3.5
通讯作者：
Champagne, J.
中科院分区：
文献类型：
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作者：
Arruda, A. G.;Godden, S.;Champagne, J.
该研究的目的是比较 3 种商业干奶牛乳腺炎制剂在产犊后乳房内感染 (IMI) 四分之一水平患病率、干奶期先前存在的感染的治愈、干奶期新感染的预防以及产犊和产奶 100 天之间临床乳腺炎病例的风险 (DIM) 方面的功效。来自 4 个不同州（加利福尼亚州、爱荷华州、明尼苏达州和威斯康星州）的 6 个商业奶牛群的总共 1,091 头奶牛（4,364 个季度）被纳入并在干奶期随机接受 3 种治疗中的一种：Quartermaster（QT；1,000,000 IU 普鲁卡因青霉素 G 和 1 g 二氢链霉素；辉瑞动物健康公司，纽约州纽约市）、Spectramast DC（SP；500 mg 盐酸头孢噻呋；辉瑞动物健康公司）或 ToMorrow Dry Cow（TM；300 mg 头孢匹林苄星乙二胺；Boehringer Ingelheim Vetmedica Inc.，St. Joseph，MO）。在干奶牛治疗之前，在干奶、0 至 6 DIM 和 7 至 13 DIM 时收集四分之一牛奶样本进行常规细菌学培养，并使用农场记录保存系统检索临床乳腺炎病例的数据。非劣效性分析用于评估治疗对主要结局（干奶期细菌学治愈风险）的影响。使用多变量逻辑回归技术来描述治疗对产后 IMI 存在风险和干奶期新 IMI 风险的影响。 Cox 比例风险回归用于描述治疗对各季度在产犊和 100 DIM 之间经历临床乳腺炎发作的风险和时间的影响。干燥期的总体粗季度感染率为 19.2%。干燥时从牛奶样品中分离出的最常见病原体是凝固酶阴性葡萄球菌，其次是气球菌属。和其他链球菌属。非劣效性分析显示治疗对断奶和产犊之间的治愈风险没有影响[最小二乘均值 (LSM)：QT = 93.3%、SP = 92.6% 和 TM = 94.0%]，二次分析显示治疗对 0 至 6 DIM 时出现 IMI 的风险没有影响（LSM：QT = 16.5%、SP = 14.1% 和 TM = 16.0%），在断奶和 0 到 6 DIM 之间出现新 IMI 的风险（LSM：QT = 14.8%，SP = 12.3%，TM = 14.2%），或者在产犊到 100 DIM 之间经历临床乳腺炎事件的风险（LSM：QT = 5.3%，SP = 3.8%，TM = 4.1%）。总之，在评估上述季度水平结果时，所评估的 3 种产品的功效没有观察到差异。
The study objective was to compare the efficacy of 3 commercial dry cow mastitis formulations regarding quarter-level prevalence of intramammary infections (IMI) postcalving, cure of preexisting infections over the dry period, prevention of new infections during the dry period, and risk for a clinical mastitis case between calving and 100 d in milk (DIM). A total of 1,091 cows (4,364 quarters) from 6 commercial dairy herds in 4 different states (California, Iowa, Minnesota, and Wisconsin) were enrolled and randomized to 1 of the 3 treatments at dry-off: Quartermaster (QT; 1,000,000 IU of procaine penicillin G and 1 g of dihydrostreptomycin; Pfizer Animal Health, New York, NY), Spectramast DC (SP; 500 mg of ceftiofur hydrochloride; Pfizer Animal Health), or ToMorrow Dry Cow (TM; 300 mg of cephapirin benzathine; Boehringer Ingelheim Vetmedica Inc., St. Joseph, MO). Quarter milk samples were collected for routine bacteriological culture before dry cow therapy treatment at dry-off, 0 to 6 DIM, and 7 to 13 DIM and an on-farm record-keeping system was used to retrieve data on clinical mastitis cases. Noninferiority analysis was used to evaluate the effect of treatment on the primary outcome, risk for a bacteriological cure during the dry period. Multivariable logistic regression techniques were used to describe the effect of treatment on risk for presence of IMI postcalving and risk of a new IMI during the dry period. Cox proportional hazards regression was used to describe the effect of treatment on the risk and time for quarters to experience an episode of clinical mastitis between calving and 100 DIM. The overall crude quarter-level prevalence of infection at dry-off was 19.2%. The most common pathogen isolated from milk samples at dry-off was coagulase-negative Staphylococcus, followed by Aerococcus spp. and other Streptococcus spp. Noninferiority analysis showed no effect of treatment on risk for a cure between dry-off and calving [least squares means (LSM): QT = 93.3%, SP = 92.6%, and TM = 94.0%] and secondary analysis showed no effect of treatment on risk for presence of an IMI at 0 to 6 DIM (LSM: QT = 16.5%, SP = 14.1%, and TM = 16.0%), risk for development of a new IMI between dry-off and 0 to 6 DIM (LSM: QT = 14.8%, SP = 12.3%, and TM = 14.2%), or risk of experiencing a clinical mastitis event between calving and 100 DIM (LSM: QT = 5.3%, SP = 3.8%, and TM = 4.1%). In conclusion, no difference was observed in efficacy among the 3 products evaluated when assessing the aforementioned quarter-level outcomes.