AgResearch Ltd., Ruakura Research Centre, 10 Bisley Road, Hamilton 3214, New Zealand; Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 4410, New Zealand.
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 4410, New Zealand.
J Dairy Sci. 2018 May;101(5):4491-4497. doi: 10.3168/jds.2017-13950. Epub 2018 Feb 21.
Numerical rating scales are frequently used in gait scoring systems as indicators of lameness in dairy animals. The gait scoring systems commonly used in dairy goats are based on 4-point scales that focus on detecting and judging the severity of a definite limp. An uneven gait, such as a shortened stride or not "tracking up," is arguably the precursor to the development of a limp; thus, identifying such changes in gait could provide opportunity for early treatment. The objectives of this study were (1) to develop a 5-point gait scoring system that included an "uneven gait" category and compare the distribution of gait scores generated using this system to scores generated using a 4-point system, and (2) to determine whether this system could be reliably used. Forty-eight Saanen cross 2- and 3-yr-old lactating does were enrolled from a commercial dairy goat farm. Two observers carried out weekly live gait scoring sessions for 7 wk using the developed 5-point scoring system. The first 2 wk were used as training sessions (training sessions 1-2), with the subsequent 5 wk completed as gait assessments (assessments 1-5). In addition to training session 1 being lived scored, the goats were also video-recorded. This allowed observer 1 to re-score the session 4 times: twice using the developed 5-point system and twice using the previously used 4-point system. Comparisons of score distributions could then be made. Using the 4-point system, 81% of the goats were assigned score 1 (normal gait). Using the 5-point system, only 36% of the goats were assigned score 1 (normal gait), with 50% assigned score 2 (uneven gait). High levels of intra-observer reliability were achieved by observer 1 using both gait scoring systems [weighted kappa (κ) = 1.00: 4-point, κ = 0.96: 5-point]. At training session 1 (wk 1), inter-observer reliability was only moderate (κ = 0.54), but this was improved during the subsequent training session 2 (κ = 0.89). Inter-observer reliability was high among assessments 1 to 5 (κ = 0.90-1.00). During the training sessions, sensitivity for gait scores 1 and 2 was 77 and 65% (training session 1) and 89 and 94% (training session 2), respectively. Sensitivity was high among assessments 1 to 5 (score 1: 83-100%, score 2: 97-100%). This highlights the likely reason why existing gait scoring systems for dairy goats do not include an "uneven gait" category, as distinguishing it from a normal gait was challenging without training. In conclusion, with training, a 5-point gait scoring system could be reliably used. The 5-point system was found to be more sensitive than the 4-point system, allowing for a potential precursor to lameness to be identified. Further work is needed to determine whether the score can be reliably used in an on-farm setting.
数字评分量表常用于奶牛动物跛行的步态评分系统中，作为跛行的指标。在奶山羊中常用的步态评分系统基于 4 分制，侧重于检测和判断明确跛行的严重程度。不均匀的步态，如缩短步幅或不“跟踪”，可以说是跛行发展的前兆；因此，识别这种步态变化可以为早期治疗提供机会。本研究的目的是：（1）制定一个包括“不均匀步态”类别的 5 分制步态评分系统，并比较使用该系统生成的步态评分分布与使用 4 分制系统生成的评分分布，（2）确定该系统是否可以可靠使用。从一家商业奶山羊场招募了 48 只萨能十字 2 至 3 岁泌乳母羊，两名观察者在 7 周内每周进行一次现场步态评分，使用开发的 5 分制评分系统进行。前 2 周用于培训（培训期 1-2），随后的 5 周完成步态评估（评估期 1-5）。除了培训期 1是现场评分外，还对山羊进行了录像。这使观察者 1可以对该会议进行 4 次重新评分：两次使用开发的 5 分制系统，两次使用以前使用的 4 分制系统。然后可以比较评分分布。使用 4 分制系统，81%的山羊被分配 1 分（正常步态）。使用 5 分制系统，只有 36%的山羊被分配 1 分（正常步态），50%的山羊被分配 2 分（不均匀步态）。观察者 1使用两种步态评分系统均实现了高水平的内部观察者可靠性[加权kappa（κ）= 1.00：4 分制，κ= 0.96：5 分制]。在培训期 1（第 1 周），观察者间的可靠性仅为中等（κ= 0.54），但在随后的培训期 2（κ= 0.89）有所提高。评估 1 至 5 之间的观察者间可靠性较高（κ= 0.90-1.00）。在培训期间，步态评分 1 和 2 的灵敏度分别为 77%和 65%（培训期 1）和 89%和 94%（培训期 2）。评估 1 至 5 的灵敏度均较高（评分 1：83-100%，评分 2：97-100%）。这突出表明了为什么现有的奶山羊步态评分系统不包括“不均匀步态”类别的原因，因为如果没有培训，区分它与正常步态具有挑战性。总之，经过培训，5 分制步态评分系统可以可靠使用。与 4 分制系统相比，该系统的灵敏度更高，从而可以识别出跛行的潜在前兆。还需要进一步的工作来确定该评分是否可以在农场环境中可靠使用。
