Introduction: While treatment frequency as an indicator of antimicrobial consumption is often assessed using defined doses, it can also be calculated directly as an Animal Treatment Index (ATI). In this study, the correlation of calculating antimicrobial usage on Swiss pig farms using either national Defined Daily Doses (DDDch) or an ATI (number of treatments per animal per year) and the agreement between the different methods for the identification of high usage farms were investigated.

Material and Methods: The antimicrobial consumption of 893 Swiss pig herds was calculated separately for suckling piglets, weaned piglets, fattening pigs, lactating and gestating sows using the indicators nDDDch (number of DDDch) per animal per year and ATI. Correlations between the indicators were investigated by calculating Spearman's Rho coefficients. The 5, 10, and 25% highest usage farms were determined by applying both methods and the interrater reliability was described using Cohen's Kappa coefficients and visualized by Bland-Altman plots.

Results: The Spearman's Rho coefficients showed strong correlations (r > 0.5) between nDDDch/animal/year and ATI. The lowest coefficient was shown for the correlation of both indicators in gestating sows (r = 0.657) and the highest in weaned piglets (r = 0.910). Kappa coefficients identifying high usage farms were the highest in weaned piglets (k = 0.71, 0.85, and 0.91, respectively for 5, 10, and 25% most frequent users) and the lowest in gestating sows (k = 0.54, 0.58, and 0.55 for 5, 10, and 25% most frequent users).

Conclusions: In general, the investigated indicators showed strong correlations and a broad agreement in terms of the calculated levels of antimicrobial usage and the identification of high usage farms. Nevertheless, a certain proportion of the farms were defined differently depending on the indicator used. These differences varied by age category and were larger in all age categories except weaned piglets when a higher percentage benchmark was used to define high usage farms. These aspects should be considered when designing scientific studies or monitoring systems and considering which indicator to use.

介绍：虽然通常使用确定的剂量来评估治疗频率作为抗菌药物消耗的指标，但也可以直接将其作为动物治疗指数（ATI）进行计算。在这项研究中，使用国家规定的每日剂量（DDDch）或ATI（每只动物每年的治疗数量）来计算瑞士养猪场的抗菌药物使用量的相关性，以及识别高使用率猪场的不同方法之间的一致性。调查。

材料与方法：使用每只动物每年的nDDDch（DDDch数）指标和ATI，分别计算了893头瑞士猪群的抗菌药物消耗量，包括哺乳仔猪，断奶仔猪，育肥猪，泌乳母猪和妊娠母猪。通过计算Spearman的Rho系数研究了指标之间的相关性。通过使用这两种方法确定了5％，10％和25％的最高使用率农场，并使用Cohen的Kappa系数描述了间际可靠性，并通过Bland-Altman图进行了可视化。

结果： Spearman的Rho系数显示出很强的相关性（[R> 0.5）在nDDDch /动物/年和ATI之间。两种母猪在妊娠母猪中的相关系数最低（[R = 0.657）和断奶仔猪中最高的仔猪（[R= 0.910）。断奶仔猪中识别高利用率农场的Kappa系数最高（ķ 对于频率最高的5、10和25％的使用者，分别为0.71、0.85和0.91），而妊娠母猪的最低（ķ 分别为5、10和25％的最频繁用户= 0.54、0.58和0.55）。

结论：一般而言，在计算出的抗菌药物使用水平和高使用率农场的鉴定方面，所调查的指标显示出很强的相关性和广泛的一致性。然而，根据所使用的指标，对一定比例的农场进行了不同的定义。这些差异随年龄段的不同而变化，除断奶仔猪以外，所有年龄段的差异都更大，而断奶仔猪则使用较高的百分比基准定义高利用率的农场。在设计科学研究或监测系统并考虑使用哪种指标时，应考虑这些方面。