Thomsen P T, Munksgaard L, Tøgersen F A
University of Aarhus, Faculty of Agricultural Sciences, Research Centre Foulum, Tjele, Denmark.
J Dairy Sci. 2008 Jan;91(1):119-26. doi: 10.3168/jds.2007-0496.
Lameness is a major problem in dairy production both in terms of reduced production and compromised animal welfare. A 5-point lameness scoring system was developed based on previously published systems, but optimized for use under field conditions. The scoring system included the words "in most cases" in the descriptions of the clinical signs evaluated. This was done to avoid a situation in which cows might not fit into any of the categories. Additionally, a number of clinical signs used in other lameness scoring systems, considered of less importance in relation to lameness, were not included. Only clinical signs were included that could easily be assessed within a few seconds from a distance. The scoring system was evaluated with intra-and interobserver agreement using kappa statistics. The evaluation was done before and after training 5 observers. Weighted kappa values ranged from 0.38 to 0.78 for intraobserver agreement, with mean kappa values across all observers of 0.60 and 0.53 before and after training, respectively. Weighted kappa values ranged from 0.24 to 0.68 for interobserver agreement, with mean kappa values across all pairs of observers of 0.48 and 0.52 before and after training, respectively. Training had only a limited positive effect on intra- and interobserver agreement. Additionally, how the different lameness categories are distributed along a theoretical scale representing the full spectrum of lameness from "absolutely normal gait" to "as lame as a cow can possibly be" was evaluated. This evaluation was done using the polychoric correlation coefficient. The estimated within-observer polychoric correlation coefficient ranged from 0.76 to 0.96, and there were no significant differences between the thresholds used to classify cows into different lameness categories by different observers before or after training. In conclusion, the results suggest that the lameness categories were not equidistant and the scoring system has reasonable reliability in terms of intra- and interobserver agreement.
跛行是奶牛生产中的一个主要问题，无论是在产量降低还是动物福利受损方面。基于先前发表的系统开发了一种5分制跛行评分系统，但针对田间条件进行了优化。该评分系统在评估的临床症状描述中包含了“在大多数情况下”这样的表述。这样做是为了避免出现奶牛可能不属于任何类别的情况。此外，其他跛行评分系统中使用的一些临床症状，若与跛行的相关性被认为较低，则未被纳入。仅纳入了可以在数秒内从远处轻松评估的临床症状。使用kappa统计量对评分系统进行了观察者内和观察者间一致性评估。在对5名观察者进行培训前后进行了评估。观察者内一致性的加权kappa值范围为0.38至0.78，所有观察者在培训前后的平均kappa值分别为0.60和0.53。观察者间一致性的加权kappa值范围为0.24至0.68，所有观察者对在培训前后的平均kappa值分别为0.48和0.52。培训对观察者内和观察者间一致性的积极影响有限。此外，还评估了不同跛行类别如何沿着一个理论量表分布，该量表代表了从“绝对正常步态”到“尽可能跛行的奶牛”的跛行全谱。使用多相相关系数进行了此评估。估计的观察者内多相相关系数范围为0.76至0.96，不同观察者在培训前后用于将奶牛分类到不同跛行类别的阈值之间没有显著差异。总之，结果表明跛行类别不是等距的，并且该评分系统在观察者内和观察者间一致性方面具有合理的可靠性。
